Peptide Research Library

Search or browse peptides and related compounds A to Z. Where a plain-English summary of the published research exists, the card links to it.

About this library

Each summary says what was studied, whether in cells, animals or people, and what the work does not show, with links to the papers. Some cover compounds that are not in the Etched Research shop.

Where an independent laboratory report exists for a compound, the measurements are published on the certificate of analysis page, including the compounds we hold no report for.

Looking for a vial rather than a paper? Browse the shop.

Peptide names, A to Z

0-9

5-Amino-1MQ

A small lab-made molecule, not a peptide, studied in mouse metabolism work.

5-Amino-1MQ is a small molecule, not a peptide. It is a quinolinium compound designed to inhibit the enzyme NNMT (nicotinamide N-methyltransferase).

Also called: 5-amino-1-methylquinolinium, 5A1MQ, 5-AMQ

Research area: Metabolism

Type of research: Animal studies · Cell studies

Research: 5-Amino-1MQ: What the Research Actually Shows

More

In the shop: 5-Amino-1MQ 50mg

A

AICAR

A nucleoside, not a peptide, used in lab research on how cells sense energy.

AICAR is a nucleoside, not a peptide. Cells add a phosphate to it, turning it into a natural intermediate in purine synthesis.

Also called: acadesine, AICA riboside, 5-aminoimidazole-4-carboxamide ribonucleoside

Research area: Cell Energy

Type of research: Animal studies · Cell studies

Research: AICAR: What the Research Actually Shows

More
  • AICAR: what the research shows. Cell and animal work on this nucleoside, not a peptide, long used as a laboratory research tool, and the heart-surgery trials run under the name acadesine.

AOD-9604

A lab-made growth hormone tail piece with one added unit, studied in metabolism research.

AOD-9604 is a synthetic peptide made from amino acids 177 to 191 of human growth hormone, with a tyrosine added at the start of the chain.

Also called: AOD9604, Tyr-hGH (177-191)

Research area: Metabolism

Research: Research page coming

ARA-290

A lab-made peptide copied from part of a kidney hormone, studied in nerve trials.

ARA-290 is a synthetic 11-amino-acid peptide modeled on one region of erythropoietin (EPO), the part known as helix B.

Also called: cibinetide, ARA 290, pHBSP (pyroglutamate helix B surface peptide)

Research area: Tissue Repair

Type of research: Human studies · Animal studies · Cell studies

One 2017 placebo-controlled trial in 64 adults measured nerve fibers in the clear front layer of the eye over 28 days (Culver 2017).

Research: ARA-290 (Cibinetide): What the Research Actually Shows

More

In the shop: ARA-290 10mg

B

B7-33

A lab-made, one-chain version of the hormone relaxin, studied in connective tissue research.

B7-33 is a synthetic single-chain peptide derived from the B chain of human relaxin-2, a two-chain peptide hormone.

Also called: single-chain relaxin-2 analog

Research area: Tissue Repair

Research: Research page coming

BPC-157

A lab-made peptide based on a stomach protein, studied in animal injury models.

BPC-157 is a synthetic 15-amino-acid peptide whose sequence was first drawn from a protein found in stomach fluid.

Also called: Body Protection Compound 157, PL 14736, PLD-116

Research area: Tissue Repair

Type of research: Animal studies · Cell studies

Research: BPC-157: What the Research Actually Shows

More

In the shop: BPC-157 10mg

BPC-157 + TB-500 blend

BPC-157 and TB-500 pre-mixed in one vial, each studied in tissue repair research.

The BPC-157 + TB-500 blend is two separate research peptides, BPC-157 and TB-500, pre-blended in one vial.

Also called: BPC/TB blend

Research area: Tissue Repair

Type of research: Animal studies

One 2026 study in 32 rats with a repaired Achilles tendon found the pair did no better than either peptide alone (Biçer 2026).

Research: BPC-157 + TB-500 Blend: What the Research Actually Shows

More

In the shop: BPC-157 + TB-500 Blend 20mg

Bronchogen

A tiny four-part peptide from a Russian research program on short peptides.

Bronchogen is a synthetic four-amino-acid peptide from the Russian bioregulator research program.

Also called: Ala-Glu-Asp-Leu, AEDL

Research area: Short Peptides

Research: Research page coming

C

Cagrilintide

A long-lasting, lab-made version of the hormone amylin, studied in human metabolism trials.

Cagrilintide is a synthetic 37-amino-acid analog of amylin, a hormone released with insulin, with a fatty acid chain attached to make it long-acting.

Also called: NN0174-0833

Research area: Metabolism

Type of research: Human studies · Animal studies

One 2021 trial in 906 adults, with placebo and comparison groups, measured body weight over 26 weeks (Lau 2021).

Research: Cagrilintide: What the Research Actually Shows

More

In the shop: Cagrilintide 10mg

Cardiogen

A tiny four-part peptide from a Russian research program on short peptides.

Cardiogen is a synthetic four-amino-acid peptide from the Russian bioregulator research program.

Also called: Ala-Glu-Asp-Arg, AEDR

Research area: Short Peptides

Research: Research page coming

Cartalax

A tiny three-part peptide from a Russian research program on short peptides.

Cartalax is a synthetic three-amino-acid peptide from the Russian bioregulator research program.

Also called: Ala-Glu-Asp, AED

Research area: Short Peptides

Research: Research page coming

Chonluten

A tiny three-part peptide from a Russian program, modeled on airway lining peptides.

Chonluten is a synthetic three-amino-acid peptide from the Russian bioregulator research program, modeled on peptides isolated from bronchial mucosa.

Also called: Glu-Asp-Gly, EDG

Research area: Short Peptides

Research: Research page coming

CJC-1295

A lab-made, longer-lasting version of the brain’s growth hormone release signal, studied in people.

CJC-1295 is a synthetic 29-amino-acid analog of GHRH (growth hormone releasing hormone) with four amino acids swapped. The “with DAC” version adds a chemical group (DAC) that binds albumin in the blood, and the version without it is also called modified GRF (1-29).

Also called: CJC-1295 with DAC, CJC-1295 without DAC, modified GRF (1-29), Mod GRF 1-29

Research area: Growth Hormone Signaling

Type of research: Human studies · Animal studies

Two 2006 placebo-controlled trials in healthy adults measured growth hormone and IGF-1 blood levels after doses of the with-DAC form (Teichman 2006).

Research: CJC-1295: What the Research Actually Shows · CJC-1295 With DAC vs Without DAC

More
  • CJC-1295: what the research shows. Trial and animal literature on this lab-made version of growth hormone releasing hormone and the growth hormone and IGF-1 levels measured.

Side by side: Ipamorelin vs CJC-1295

CJC-1295 + Ipamorelin blend

Two peptides, CJC-1295 and Ipamorelin, pre-mixed in one vial, each studied on its own.

The CJC-1295 + Ipamorelin blend is two separate research peptides, CJC-1295 and Ipamorelin, pre-blended in one vial.

Also called: CJC/Ipa blend

Research area: Growth Hormone Signaling

Research: CJC-1295 + Ipamorelin Blend: What the Research Actually Shows

More

Cortagen

A tiny four-part peptide from a Russian program, modeled on brain tissue peptides.

Cortagen is a synthetic four-amino-acid peptide from the Russian bioregulator research program, modeled on peptides isolated from the cerebral cortex.

Also called: Ala-Glu-Asp-Pro, AEDP

Research area: Short Peptides

Research: Research page coming

D

DSIP

A small peptide first found in rabbits in 1977, studied in sleep research.

DSIP is a nine-amino-acid peptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) first isolated from rabbits in 1977. No gene, precursor protein or receptor for it has been identified.

Also called: delta sleep-inducing peptide, emideltide

Research area: Brain & Nerves

Type of research: Animal studies

Research: DSIP: What the Research Actually Shows

More
  • DSIP: what the research shows. Animal sleep and brain-wave studies on this nine-amino-acid peptide, the small human trials and their weak results, and the absence of any identified gene or receptor.

E

Epithalon

A tiny peptide based on a pineal gland extract, studied in chromosome-tip (telomere) research.

Epithalon is a synthetic four-amino-acid peptide modeled on epithalamin, an extract of the pineal gland. It is not the same thing as the extract.

Also called: Epitalon, Epithalone, AEDG, Ala-Glu-Asp-Gly

Research area: Cell Energy · Short Peptides

Type of research: Human studies · Animal studies · Cell studies

Two small uncontrolled Russian reports, with no group sizes given, measured night-time melatonin and retina activity in people (Korkushko 2007, Khavinson 2002).

Research: Epithalon: Bioregulator Peptide Research

More

In the shop: Epithalon 10mg

F

FOXO4-DRI

A lab-made, mirror-image piece of the protein FOXO4, studied in cell research.

FOXO4-DRI is a synthetic peptide modeled on a region of the FOXO4 protein, built from D-amino acids in reversed order (a retro-inverso peptide) so enzymes break it down more slowly.

Also called: FOXO4 D-retro-inverso peptide

Research area: Cell Energy

Research: Research page coming

G

GHK-Cu

A tiny copper-bound peptide, first found in blood, studied in tissue repair research.

GHK-Cu is a three-amino-acid peptide, glycine, histidine and lysine, bound to a copper ion.

Also called: prezatide copper, GHK (the peptide without copper), glycyl-L-histidyl-L-lysine

Research area: Tissue Repair

Type of research: Human studies · Animal studies · Cell studies

One 1994 placebo-controlled trial, size not given in its abstract, measured tissue closure on the sole of the foot (Mulder 1994).

Research: GHK-Cu: What the Research Actually Shows

More

In the shop: GHK-Cu

GHRP-6

A small lab-made peptide, one of the earliest in growth hormone release research.

GHRP-6 is a synthetic six-amino-acid peptide, one of the first growth hormone releasing peptides described, that binds the ghrelin receptor.

Also called: growth hormone releasing peptide 6

Research area: Growth Hormone Signaling

Research: GHRP-6: What the Research Actually Shows

GLOW blend

A market name for GHK-Cu, BPC-157 and TB-500 pre-mixed in one vial.

GLOW is three separate research peptides, GHK-Cu, BPC-157 and TB-500, pre-blended in one vial. GLOW is the name the market uses for this blend, not the name of a compound.

Also called: GLOW

Research area: Tissue Repair

Research: We found no published study that tested the three in combination, so GLOW has no research page of its own. Each component’s research page is linked in its own entry, and the KLOW research summary covers all three as components.

In the shop: GLOW Blend 70mg

Gonadorelin

A lab-made copy of the brain’s signal that starts the reproductive hormone chain.

Gonadorelin is the synthetic form of gonadotropin-releasing hormone (GnRH), the ten-amino-acid hormone made in the hypothalamus that signals the pituitary.

Also called: GnRH, LHRH, gonadotropin-releasing hormone

Research area: Reproductive Hormones

Research: Research page coming

H

HCG

A hormone made by the placenta in pregnancy, studied in reproductive hormone research.

HCG is a glycoprotein hormone made of two protein subunits, alpha and beta, that hold together without a covalent bond. It is made naturally by the placenta and is also produced in the lab.

Also called: human chorionic gonadotropin, hCG

Research area: Reproductive Hormones

Type of research: Human studies

One 2005 randomized study in 29 healthy men measured hormone levels inside the testes, and two later reports reviewed past records (Coviello 2005).

Research: HCG: What the Research Actually Shows

More

Hexarelin

A small lab-made peptide in growth hormone research, also studied in heart tissue.

Hexarelin is a synthetic six-amino-acid peptide (a hexapeptide) that binds the ghrelin receptor.

Also called: examorelin

Research area: Growth Hormone Signaling

Type of research: Human studies · Animal studies

One 2004 placebo-controlled study in 7 young adults measured sleep patterns and hormone levels through the night (Frieboes 2004).

Research: Hexarelin research

More
  • Hexarelin research. Ghrelin-receptor activity and the separate work on a second receptor it binds in heart tissue.

HGH Fragment 176-191

A lab-made copy of growth hormone’s tail end, studied in metabolism research.

HGH Fragment 176-191 is a synthetic peptide matching amino acids 176 to 191, the tail end of the human growth hormone chain.

Also called: hGH 176-191, Fragment 176-191

Research area: Metabolism

Research: Research page coming

Humanin

A small peptide coded in the cell’s power plants (mitochondria), studied in cell research.

Humanin is a 24-amino-acid peptide encoded in mitochondrial DNA, inside the gene for 16S ribosomal RNA.

Also called: HN

Research area: Cell Energy

Research: Research page coming

I

IGF-1

A growth factor the liver makes on growth hormone’s signal, studied in human trials.

IGF-1 is a 70-amino-acid growth factor made mostly in the liver after growth hormone signals it.

Also called: insulin-like growth factor 1, mecasermin (the recombinant form)

Research area: Growth Hormone Signaling

Type of research: Human studies

One 2007 study followed 76 children who make too little IGF-1 and measured height growth for up to 12 years (Chernausek 2007).

Research: IGF-1: What the Research Actually Shows

More

IGF-1 DES

A shorter natural form of the growth factor IGF-1, missing its first three units.

IGF-1 DES is a shortened form of IGF-1 missing its first three amino acids, which also occurs naturally.

Also called: IGF-1 (4-70), des(1-3)IGF-1

Research area: Growth Hormone Signaling

Research: Research page coming

IGF-1 LR3

A longer, lab-made form of growth factor IGF-1, mostly used to grow cells in labs.

IGF-1 LR3 is a synthetic 83-amino-acid analog of IGF-1, with arginine swapped in at position 3 and a 13-amino-acid extension added at the start of the chain.

Also called: Long R3 IGF-I, LR3 IGF-I, LongR3

Research area: Growth Hormone Signaling

Type of research: Animal studies · Cell studies

Research: IGF-1 LR3: What the Research Actually Shows

More

In the shop: IGF-1 LR3 1mg

Ipamorelin

A five-part lab-made peptide studied in growth hormone release research.

Ipamorelin is a synthetic five-amino-acid peptide that binds the ghrelin receptor.

Also called: NNC 26-0161

Research area: Growth Hormone Signaling

Type of research: Human studies · Animal studies · Cell studies

One 1999 study in 40 healthy men measured blood levels and growth hormone pulses after single doses (Gobburu 1999).

Research: Ipamorelin: What the Research Actually Shows

More

Side by side: Ipamorelin vs CJC-1295 · Tesamorelin vs Ipamorelin

In the shop: Ipamorelin 10mg

K

Kisspeptin-10

The shortest active piece of kisspeptin, a brain signal studied in reproductive hormone research.

Kisspeptin-10 is the last ten amino acids of kisspeptin-54, a peptide the body makes from the kisspeptin gene, and the shortest piece of it that stays active at its receptor.

Also called: KP-10, metastin (45-54)

Research area: Reproductive Hormones

Type of research: Human studies · Animal studies

One 2018 study in 25 boys and 5 men measured reproductive hormone levels in the blood for 2 hours after one dose (Nabi 2018).

Research: Kisspeptin-10 research

More
  • Kisspeptin-10 research. Its place at the top of the chain of signals from the brain to the reproductive glands, and its use in reproductive hormone research.

KLOW blend

A market name for GHK-Cu, BPC-157, TB-500 and KPV pre-mixed in one vial.

KLOW is four separate research peptides, GHK-Cu, BPC-157, TB-500 and KPV, pre-blended in one vial. KLOW is the name the market uses for this blend, not the name of a compound.

Also called: KLOW

Research area: Tissue Repair

Research: KLOW Blend: BPC-157, TB-500, GHK-Cu, KPV

More

In the shop: KLOW Blend 80mg

KPV

The last three units of a pituitary hormone, studied in animal gut inflammation work.

KPV is a three-amino-acid peptide, lysine, proline and valine, matching the last three amino acids of alpha-MSH, a natural hormone made in the pituitary, the brain and other tissues.

Also called: Lys-Pro-Val, alpha-MSH (11-13)

Research area: Immune System

Type of research: Animal studies · Cell studies

Research: KPV: What the Research Actually Shows

More
  • KPV: what the research shows. Preclinical work on this three-amino-acid piece of a pituitary hormone in models of intestinal inflammation.

In the shop: KPV 10mg

L

Livagen

A tiny four-part peptide from a Russian program, modeled on liver tissue peptides.

Livagen is a synthetic four-amino-acid peptide from the Russian bioregulator research program, modeled on peptides isolated from liver tissue.

Also called: Lys-Glu-Asp-Ala, KEDA

Research area: Short Peptides

Research: Research page coming

LL-37

A natural peptide from the body’s germ-fighting defenses, studied in immune research.

LL-37 is a 37-amino-acid peptide cut from human cathelicidin, named for the two leucines at its start and its length.

Also called: cathelicidin LL-37, hCAP18 (its precursor protein)

Research area: Immune System

Research: Research page coming

M

MGF and PEG-MGF

Pieces of a growth factor that stretched muscle makes, a form of IGF-1.

MGF is a form of IGF-1 made by alternative splicing of the IGF-1 gene. The research peptide called MGF is usually a synthetic piece of its E domain, and PEG-MGF is the same peptide with polyethylene glycol attached.

Also called: mechano growth factor, IGF-1Ec, pegylated MGF

Research area: Growth Hormone Signaling

Research: MGF and PEG-MGF: What the Research Shows

MOTS-c

A peptide coded in the cell’s power plants, studied in mouse and cell metabolism work.

MOTS-c is a 16-amino-acid peptide encoded in mitochondrial DNA, inside the gene for 12S ribosomal RNA.

Also called: mitochondrial open reading frame of the 12S rRNA-c

Research area: Cell Energy

Type of research: Animal studies · Cell studies

Research: MOTS-c: What the Research Actually Shows

More
  • MOTS-c: what the research shows. Animal and cell literature on this peptide encoded in mitochondrial DNA, and the work on cell energy sensing and insulin signaling.

Side by side: MOTS-c vs NAD+

In the shop: MOTS-c

N

N-acetyl Epithalon Amidate

A lab-made variant of Epithalon with small caps added to both ends.

N-acetyl Epithalon Amidate is a modified form of Epithalon with an acetyl group on one end of the chain and an amide on the other.

Also called: Ac-Epithalon-NH2, N-acetyl Epitalon amidate

Research area: Cell Energy · Short Peptides

Research: Research page coming

NAD+

Not a peptide: a helper molecule that many cell enzymes need to work.

NAD+ is a coenzyme, not a peptide, made of two nucleotides joined through their phosphate groups.

Also called: nicotinamide adenine dinucleotide, beta-NAD, nadide, coenzyme I

Research area: Cell Energy

Type of research: Human studies · Animal studies · Cell studies

One 2019 pilot gave NAD+ to 8 of 11 healthy men and measured blood and urine levels over 6 hours (Grant 2019).

Research: NAD+: What Researchers Have Actually Studied

More

Side by side: MOTS-c vs NAD+

In the shop: NAD+ 500mg

O

Ovagen

A tiny three-part peptide from a Russian research program on short peptides.

Ovagen is a synthetic three-amino-acid peptide from the Russian bioregulator research program.

Also called: Glu-Asp-Leu, EDL

Research area: Short Peptides

Research: Research page coming

Oxytocin

A natural nine-part hormone from the brain, studied in brain signaling research.

Oxytocin is a nine-amino-acid peptide hormone made in the hypothalamus and released from the posterior pituitary.

Also called: OT, OXT

Research area: Brain & Nerves

Research: Research page coming

P

P21

A lab-made peptide based on a nerve growth signal, studied in mouse brain research.

P21 is a small synthetic peptide modeled on a fragment of ciliary neurotrophic factor (CNTF), a natural nerve growth signal.

Also called: P021

Research area: Brain & Nerves

Type of research: Animal studies · Cell studies

Research: P21: What the Research Actually Shows

More

Pancragen

A tiny four-part peptide from a Russian program, modeled on pancreas tissue peptides.

Pancragen is a synthetic four-amino-acid peptide from the Russian bioregulator research program, modeled on peptides isolated from pancreatic tissue.

Also called: Lys-Glu-Asp-Trp, KEDW

Research area: Short Peptides

Research: Research page coming

PE-22-28

A shortened lab-made version of spadin, a brain protein fragment, studied in mice.

PE-22-28 is a synthetic seven-amino-acid peptide, a shortened analog of spadin, which itself comes from the propeptide of the protein sortilin.

Also called: spadin analog

Research area: Brain & Nerves

Research: Research page coming

Prostamax

A tiny four-part peptide from a Russian research program on short peptides.

Prostamax is a synthetic four-amino-acid peptide from the Russian bioregulator research program.

Also called: Lys-Glu-Asp-Pro, KEDP

Research area: Short Peptides

Research: Research page coming

PT-141

A ring-shaped lab-made peptide that acts on a brain signaling system called melanocortin.

PT-141 is a synthetic cyclic seven-amino-acid peptide modeled on a natural melanocortin hormone, and it binds melanocortin receptors.

Also called: bremelanotide, PT 141, PT141

Research area: Brain & Nerves

Type of research: Human studies

Two 2019 placebo-controlled trials in 1,267 women measured questionnaire scores over 24 weeks (Kingsberg 2019).

Research: PT-141: What the Research Actually Shows

More

In the shop: PT-141 10mg

R

Retatrutide

A lab-made peptide that acts on three hormone receptors, studied in human metabolism trials.

Retatrutide is a synthetic 39-amino-acid peptide with a fatty acid chain attached, built to act at the receptors for three hormones: glucagon and two gut hormones, GIP and GLP-1.

Also called: LY3437943

Research area: Metabolism

Type of research: Human studies · Animal studies · Cell studies

One 2026 placebo-controlled trial in 537 adults measured a long-term blood sugar marker and body weight over 40 weeks (Bajaj 2026).

Research: Retatrutide: What the Research Actually Shows

More
  • Retatrutide: what the research shows. The published phase 1 to phase 3 trial literature on this peptide that acts at three hormone receptors, and the measures those trials recorded.

In the shop: Retatrutide

S

Selank

A peptide developed in Russia from a natural immune fragment, studied in brain research.

Selank is a synthetic seven-amino-acid peptide developed by Russian researchers. It is tuftsin, a natural four-amino-acid peptide, with three more amino acids added.

Also called: TP-7, Thr-Lys-Pro-Arg-Pro-Gly-Pro

Research area: Brain & Nerves

Type of research: Human studies · Animal studies · Cell studies

Two small Russian studies, about 60 adults each, compared it with a prescription drug on symptom scores, with no placebo group (Zozulia 2008).

Research: Selank: What the Research Actually Shows

More

Side by side: Semax vs Selank

In the shop: Selank 10mg

Semax

A peptide developed in Russia from part of a stress hormone, studied in brain research.

Semax is a synthetic seven-amino-acid peptide built from a short fragment of adrenocorticotropic hormone (ACTH), a stress hormone made by the pituitary, with three amino acids added to the end.

Also called: ACTH(4-7)PGP, Met-Glu-His-Phe-Pro-Gly-Pro

Research area: Brain & Nerves

Type of research: Human studies · Animal studies

One 2018 Russian study in 110 adults, with no placebo group, measured movement, daily function and a nerve growth signal in the blood (Gusev 2018).

Research: Semax: What the Research Actually Shows

More

Side by side: Semax vs Selank

In the shop: Semax 10mg

Sermorelin

A lab-made copy of the first 29 units of the brain’s growth hormone signal.

Sermorelin is a synthetic peptide made of the first 29 amino acids of growth hormone releasing hormone (GHRH), the brain’s 44-amino-acid signal for growth hormone release.

Also called: GRF (1-29), GHRH (1-29)

Research area: Growth Hormone Signaling

Research: Sermorelin research

More

SLU-PP-332

A lab-made small molecule, not a peptide, studied in mouse cell energy research.

SLU-PP-332 is a synthetic small molecule, not a peptide, that binds a family of nuclear receptors called estrogen-related receptors (ERRs). It is not related to estrogen in structure.

Also called: SLU-PP332

Research area: Cell Energy

Type of research: Animal studies · Cell studies

Research: SLU-PP-332: What the Research Actually Shows

More
  • SLU-PP-332: what the research shows. Cell and mouse literature on this synthetic small molecule, not a peptide, which activates a family of nuclear receptors called estrogen-related receptors, and the absence of any human trial.

SS-31

A lab-made peptide built to reach the cell’s power plants, studied in human trials.

SS-31 is a synthetic four-amino-acid peptide built to reach the inner membrane of mitochondria, where it binds the lipid cardiolipin.

Also called: elamipretide, MTP-131, Szeto-Schiller peptide 31

Research area: Cell Energy

Type of research: Human studies · Cell studies

One 2023 placebo-controlled trial in 218 adults measured walking distance and tiredness scores over 24 weeks (Karaa 2023).

Research: SS-31: What the Research Actually Shows

More

In the shop: SS-31 10mg

T

TB-500

A name used for thymosin beta-4, a common cell protein, and for a short piece of it.

TB-500 is a name used for two things: thymosin beta-4, a 43-amino-acid protein found in most cells, and a short synthetic fragment of it. The research page explains which is which.

Also called: thymosin beta-4, Tβ4

Research area: Tissue Repair

Type of research: Human studies · Animal studies · Cell studies

One 2015 placebo-controlled trial of the full protein, not the short piece, in 72 adults measured eye-surface signs over 28 days (Sosne 2015).

Research: TB-500: What the Research Actually Shows

More

In the shop: TB-500 10mg

Tesamorelin

A lab-made, stable version of the brain’s growth hormone signal, studied in human trials.

Tesamorelin is a synthetic analog of growth hormone releasing hormone (GHRH) that carries the full 44-amino-acid sequence with a small chemical group added to its first amino acid.

Also called: TH9507

Research area: Growth Hormone Signaling

Type of research: Human studies

One 2007 placebo-controlled trial in 412 adults measured visceral fat, the deep fat around the organs, over 26 weeks (Falutz 2007).

Research: Tesamorelin: What the Research Actually Shows

More

Side by side: Tesamorelin vs Ipamorelin

In the shop: Tesamorelin 10mg

Thymagen

A two-part peptide from a Russian program, modeled on thymus tissue peptides.

Thymagen is a synthetic two-amino-acid peptide from the Russian bioregulator research program, modeled on peptides isolated from thymus tissue.

Also called: Thymogen, Glu-Trp, EW

Research area: Short Peptides

Research: Research page coming

Thymalin

A mix of short peptides from calf thymus, an immune organ, developed in Russia.

Thymalin is a mixture of short peptides extracted from calf thymus tissue, developed in Russia.

Also called: thymus peptide extract

Research area: Immune System

Research: Research page coming

Thymosin Alpha-1

A peptide first found in the thymus, an immune organ, studied in human trials.

Thymosin Alpha-1 is a 28-amino-acid peptide first isolated from thymus tissue and now made by synthesis.

Also called: thymalfasin, Tα1, TA1

Research area: Immune System

Type of research: Human studies

One 2025 placebo-controlled trial in 1,106 adults in intensive care counted deaths from any cause over 28 days (Wu 2025).

Research: Thymosin Alpha-1: What the Research Actually Shows

More

In the shop: Thymosin Alpha-1 10mg

Thymulin

A nine-part thymus peptide that holds a zinc atom, used in immune research.

Thymulin is a nine-amino-acid peptide made by the thymus that binds a zinc ion.

Also called: facteur thymique serique, FTS, serum thymic factor

Research area: Immune System

Research: Research page coming

TRH

A tiny three-part brain hormone that starts the thyroid signal chain.

TRH is a three-amino-acid hormone made in the hypothalamus.

Also called: thyrotropin-releasing hormone, protirelin, pGlu-His-Pro-NH2

Research area: Brain & Nerves

Research: Research page coming

V

Vesugen

A tiny three-part peptide from a Russian program, modeled on blood vessel peptides.

Vesugen is a synthetic three-amino-acid peptide from the Russian bioregulator research program, modeled on peptides isolated from blood vessel walls.

Also called: Lys-Glu-Asp, KED

Research area: Short Peptides

Research: Research page coming

VIP

A natural peptide found in the gut and brain, studied in immune signaling research.

VIP is a 28-amino-acid neuropeptide found in the gut, the brain and other tissues.

Also called: vasoactive intestinal peptide

Research area: Immune System

Research: VIP: what the research shows

More
  • VIP: what the research shows. A natural 28-amino-acid neuropeptide, first isolated from the gut in 1970, examined in receptor and immune-cell studies.

Vilon

A two-part peptide, one of the smallest from the Russian short-peptide program.

Vilon is a synthetic two-amino-acid peptide from the Russian bioregulator research program.

Also called: Lys-Glu, KE

Research area: Short Peptides

Research: Research page coming

Last reviewed: 2026-10-03

Peptide Basics

Storage, reading a lab report, checking a seller, key terms

These pages answer the questions that sit underneath the compound pages: what a research peptide is in regulatory terms, how lyophilized material holds up in storage, and how to judge a source.

Research areas

Growth Hormone Signaling

How the brain and pituitary trigger growth hormone release

Growth hormone signaling research follows the chain that sets growth hormone release: a signal from the brain (growth hormone releasing hormone), the pulses the pituitary releases in answer, and IGF-1, a growth factor made downstream. The compounds here act at different points on that chain, through the receptor for that brain signal, the ghrelin receptor, or the IGF-1 receptor itself.

Shop growth hormone signaling research peptides

Side by side: Ipamorelin vs CJC-1295 · CJC-1295 with DAC vs without · Tesamorelin vs Ipamorelin

Metabolism

How the body uses sugar and balances its energy

Metabolism research covers the hormone receptors and cellular enzymes that govern energy balance and glucose handling. The literature runs from multi-site human trials for some receptor agonists to mouse studies alone for enzyme inhibitors such as 5-Amino-1MQ.

Shop metabolism research compounds

Cell Energy

How cells make and use energy, plus related cell studies

Mitochondrial research looks at how cells make and manage energy, from the inner mitochondrial membrane to the NAD+ supply many cellular enzymes depend on. Related work looks at other cell systems, such as telomerase activity and telomere length, in cells and animal models.

Shop cell energy research peptides

Side by side: MOTS-c vs NAD+

Tissue Repair

Tendon, ligament and muscle injury studies, mostly in animals

Tissue repair research studies how tendon, ligament, muscle and other connective tissue rebuild after injury, through cell migration, new blood vessel growth and remodeling of the surrounding matrix. Most of the published work is in rats and cell culture, and human trials exist for only a few of these compounds.

Shop tissue repair research peptides · Single-vial blends

Brain & Nerves

Peptides studied in the brain and nervous system

Neuropeptide research studies short peptides that act on the brain and nervous system, mostly in animal models of stress and injury. Much of the literature on Semax and Selank comes from Russian research groups, and English-language replication is thin.

Shop brain and nerve research peptides

Side by side: Semax vs Selank

Immune System

Immune cell signaling and inflammation studies

Immune research examines how peptides interact with T-cell development, innate immune signaling and inflammation pathways. The record runs from randomized trials for Thymosin Alpha-1 to animal and cell models alone for KPV.

Shop immune system research peptides

Reproductive Hormones

How the brain and pituitary signal the reproductive glands

Reproductive hormone research follows the chain from the brain to the reproductive glands (the hypothalamic-pituitary-gonadal axis): the gonadotropin-releasing hormone and kisspeptin signals from the brain, the gonadotropins the pituitary releases in answer, and the hormones the gonads make downstream.

Short Peptides (Bioregulators)

Russian bioregulator peptides, two to four amino acids long

Bioregulators are short peptides, most of them two to four amino acids long, that came out of one research program in Russia. The evidence is thin, mostly small studies published in Russian-language journals.

Epithalon is in the shop, listed under cell energy research.

Lab and regulatory terms

This glossary defines the terms that show up on peptide lab reports, in the research literature and in US regulation. Each entry opens with a plain definition, then links to the page on this site that covers it in more depth.

For the compounds themselves, start in the research library. Where an independent laboratory report exists for a compound, the measurements are published on the certificate of analysis page, including the compounds we hold no report for. The full catalog is in the shop.

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503A

Regulatory

503A is the section of the Federal Food, Drug, and Cosmetic Act that covers compounding by a licensed pharmacist or physician for a specific person named on a prescription. A 503A compounder may use only bulk ingredients that meet set criteria, such as a United States Pharmacopeia (USP) monograph, a component of an FDA-approved drug, or a place on the FDA’s 503A bulks list.

503B

Regulatory

503B is the section of the same act that covers outsourcing facilities, compounders registered with the FDA that can make larger batches with or without prescriptions. They are inspected by the FDA and must follow current good manufacturing practice.

A

Acetate salt

Chemistry and form

An acetate salt is a peptide paired with acetate as its counterion, often made by exchanging the trifluoroacetate left over from purification. The salt form changes the powder’s weight and formula but not the peptide sequence.

Go deeper: Synthetic Peptide vs Recombinant Protein

Agonist

Chemistry and form

An agonist is a molecule that binds a receptor and activates it, producing the same kind of signal as the body’s own messenger. An antagonist binds the same receptor and blocks it instead.

Go deeper: Ipamorelin: What the Research Actually Shows

Amino acid

Chemistry and form

An amino acid is a small molecule carrying an amino group and a carboxyl group, and it is the building block of peptides and proteins. Biology builds proteins from 20 standard amino acids, and synthetic chemistry can use many more.

Go deeper: The 40-Amino-Acid Line in the FDA Protein Rule

Analog

Chemistry and form

An analog is a compound modeled on a parent molecule with one or more deliberate changes, such as a swapped amino acid or an added chemical group. Analogs are usually designed to change stability, receptor selectivity or how long the molecule lasts.

Go deeper: Tesamorelin: What the Research Actually Shows

Area percent

Testing and analysis

Area percent is how HPLC purity is usually calculated: the area under the main peak divided by the total area of all the peaks the detector picked up. It only counts what the detector can see at the wavelength used, so water, salts and some contaminants are not part of the figure.

B

Biologic

Regulatory

A biologic (biological product) is an FDA category, set by the Public Health Service Act, that covers most proteins and other products made from living sources, with its own approval pathway. A chain made entirely by chemical synthesis and under 100 amino acids is excluded and regulated as a drug instead, and a chain of 40 amino acids or fewer is not a protein under the rule at all.

Go deeper: Peptide, Protein, Biologic: How the FDA Draws Lines

Bulk drug substance categories

Regulatory

The FDA’s bulk drug substance categories sort ingredients nominated for use in 503A compounding while the agency reviews them. Category 1 is under evaluation, Category 2 is flagged for significant safety risks, and Category 3 was nominated without enough supporting information.

C

CAS number

Chemistry and form

A CAS number (CAS Registry Number) is a unique identifier that Chemical Abstracts Service, a division of the American Chemical Society, assigns to a specific chemical substance. Different forms of one compound, such as a salt or a metal complex, can carry different numbers, and a custom mixture generally has none of its own.

Chromatogram

Testing and analysis

A chromatogram is the graph an HPLC run produces, with time along one axis and detector signal along the other. Each peak is a separated component, and on a peptide report the largest peak should be the target compound.

Clinical trial phase

Chemistry and form

A clinical trial phase is the stage of human research a study belongs to: Phase 1 looks mainly at safety in a small group, Phase 2 looks for early signs of an effect, and Phase 3 is a large, usually randomized trial. A phase describes a study’s stage, not the strength of its result.

Go deeper: Thymosin Alpha-1: What the Research Actually Shows

COA (certificate of analysis)

Testing and analysis

A COA (certificate of analysis) is a lab document reporting what was measured on a specific sample: the tests run, the methods, the results, the date and the sample or lot it describes. It describes the material that lab received, and it only describes a given vial if both carry the same lot number.

Go deeper: certificate of analysis page

Counterion

Chemistry and form

A counterion is an ion of opposite charge that pairs with a charged peptide to form a neutral salt. Common counterions in synthetic peptides are acetate, trifluoroacetate and chloride, and they add weight to the powder without being peptide.

Go deeper: Synthetic Peptide vs Recombinant Protein

E

Endotoxin

Testing and analysis

Endotoxin is lipopolysaccharide (LPS), a molecule from the outer membrane of Gram-negative bacteria that can trigger fever and inflammation in mammals. It is heat stable, so a material can be sterile and still contain endotoxin, which is why it is tested separately.

Go deeper: Synthetic Peptide vs Recombinant Protein

F

FDA

Regulatory

The FDA (US Food and Drug Administration) is the federal agency within the Department of Health and Human Services that regulates drugs, biologics, medical devices and food, among other products, under the Federal Food, Drug, and Cosmetic Act. Its definitions decide which rulebook a molecule falls under, including the line between a peptide and a protein.

Go deeper: Peptide, Protein, Biologic: How the FDA Draws Lines

Fill weight

Testing and analysis

Fill weight is the amount of material dispensed into a vial, which the label states in milligrams. A lab checks it by measuring net content and comparing the two numbers.

Go deeper: certificate of analysis page

Fragment

Chemistry and form

A fragment is a piece of a longer peptide or protein, often named by the positions it covers counted from the N-terminus, as in (1-29). A fragment and its parent are different molecules and are tested and described separately.

Go deeper: TB-500: What the Research Actually Shows

G

GMP (CGMP)

Regulatory

GMP (good manufacturing practice), written by the FDA as CGMP for current good manufacturing practice, is the set of rules for how drugs are made, tested, documented and released so that each batch meets its specification. For finished drugs in the US the rules are in the Code of Federal Regulations, title 21, parts 210 and 211.

H

Half-life

Chemistry and form

Half-life is the time it takes for the amount of a compound to fall by half. In the literature it can mean how long a molecule lasts in circulation in a study animal or participant, or how long it stays intact in a lab solution, so check which one a source means.

Go deeper: CJC-1295 With DAC vs Without DAC

HPLC

Testing and analysis

HPLC (high-performance liquid chromatography) is a lab method that pushes a dissolved sample through a tightly packed column under high pressure, so the molecules in it separate and reach the detector at different times. On a peptide report it is the method behind the purity figure.

Go deeper: Synthetic Peptide vs Recombinant Protein

I

Identity test

Testing and analysis

An identity test confirms that a material is the compound named on its label, usually by mass spectrometry. A matching mass is strong evidence, but on its own it cannot tell apart two molecules built from the same atoms in a different order.

Go deeper: certificate of analysis page

In vitro

Chemistry and form

In vitro (Latin for “in glass”) describes research done on cells, tissues or molecules outside a living organism, such as cells grown in a dish. A result in vitro shows what happened in that system, not what happens in a whole animal or person.

Go deeper: BPC-157: What the Research Actually Shows

In vivo

Chemistry and form

In vivo (Latin for “in the living”) describes research done inside a living organism, such as a mouse or a rat. Animal results often fail to carry over to people, which is why the type of study matters when reading a finding.

IND

Regulatory

An IND (Investigational New Drug application) is the filing a sponsor submits to the FDA before an unapproved drug can be shipped across state lines for use in a clinical investigation. It is the step between preclinical research and a Phase 1 trial.

Intended use

Regulatory

Intended use is the purpose a product is meant for. The FDA determines it from objective evidence, such as labeling, advertising, the seller’s statements and how the product is distributed, and it is the standard the FDA applies when deciding whether a product is regulated as a drug.

L

LAL test

Testing and analysis

The LAL test (Limulus amebocyte lysate) detects endotoxin using an extract of horseshoe crab blood cells that reacts when endotoxin is present. Labs read it as a gel clot, a change in cloudiness or a color change, and a newer version uses a lab-made reagent called recombinant factor C instead of the crab extract.

LC-MS

Testing and analysis

LC-MS (liquid chromatography with mass spectrometry) is a setup where the HPLC separation feeds straight into a mass spectrometer, so the lab can measure the mass of what is in each peak. Many peptide reports use it to confirm identity and look at purity in one run.

Lot (batch)

Testing and analysis

A lot, or batch, is a quantity of material made or received together under one identifier and expected to be uniform within set limits. The lot number is what ties a lab report to a physical vial.

Go deeper: certificate of analysis page

Lyophilized

Chemistry and form

Lyophilized means freeze-dried: the material is frozen, then its water is removed under vacuum so it passes straight from ice to vapor. The result is a dry powder or cake, which is far more stable in storage than the same compound in solution.

Go deeper: How Long Does a Lyophilized Peptide Last?

M

Mass spectrometry

Testing and analysis

Mass spectrometry is a method that turns molecules into charged particles and measures their mass-to-charge ratio. On a peptide report it confirms identity, by checking that the measured mass matches the mass expected from the sequence.

Go deeper: Synthetic Peptide vs Recombinant Protein

Molecular formula

Chemistry and form

A molecular formula lists how many atoms of each element make up one molecule, written as counts of carbon, hydrogen, nitrogen, oxygen and so on. For a salt or a metal complex the formula changes depending on whether the counterion or metal is included, so a formula should say which form it describes.

Molecular weight

Chemistry and form

Molecular weight is the mass of one molecule, the sum of the masses of its atoms, given in daltons or grams per mole. Reference listings usually give the average mass, while mass spectrometry often reports the monoisotopic mass (calculated from the most abundant isotope of each element), so the two numbers can differ slightly.

Go deeper: The 40-Amino-Acid Line in the FDA Protein Rule

N

Net content

Testing and analysis

Net content is the measured amount of the named compound in a vial, reported in milligrams and compared against the label. Labs usually measure it by HPLC against a reference standard, and the report should say whether the figure counts the bare peptide or the peptide with its salt or metal.

Go deeper: certificate of analysis page

Net peptide content

Testing and analysis

Net peptide content is the percentage of a powder’s total weight that is actual peptide, with the rest made up of water, counterions and other non-peptide material. It is a different number from purity, and a high-purity powder can still have a net peptide content well below 100 percent.

Go deeper: Synthetic Peptide vs Recombinant Protein

Non-canonical amino acid

Chemistry and form

A non-canonical amino acid is one outside the 20 standard amino acids, such as Aib (alpha-aminoisobutyric acid) or the D-form of a standard amino acid. Chemists build them into research peptides, often to slow how fast enzymes break the chain apart.

Go deeper: The 40-Amino-Acid Line in the FDA Protein Rule

P

Peptide

Chemistry and form

A peptide is a short chain of amino acids joined by peptide bonds. There is no single chemical cutoff, but chains under about 50 amino acids are usually called peptides, and the FDA draws its protein line at more than 40.

Go deeper: Peptide, Protein, Biologic: How the FDA Draws Lines

Peptide bond

Chemistry and form

A peptide bond is the link between two amino acids, formed when the carboxyl group of one joins the amino group of the next and a molecule of water is released. Water can break that bond again, a reaction called hydrolysis.

Go deeper: How Long Does a Lyophilized Peptide Last?

PMID

Chemistry and form

A PMID (PubMed identifier) is the unique number the US National Library of Medicine assigns to each record in PubMed, its index of biomedical literature. A PMID lets anyone find the exact paper a page cites, but being indexed says nothing about whether the findings hold up.

Go deeper: TB-500: What the Research Actually Shows

Preclinical

Chemistry and form

Preclinical research is the work done before any human trial, in cells and animals. A compound with only preclinical data has no human trial results to read.

Go deeper: GHK-Cu: What the Research Actually Shows

Protein

Chemistry and form

A protein is a longer chain of amino acids, usually folded into a defined shape. Under FDA regulation, a protein is an alpha amino acid polymer with a specific defined sequence of more than 40 amino acids.

Go deeper: Peptide, Protein, Biologic: How the FDA Draws Lines

Purity

Testing and analysis

Purity, on a peptide report, is the share of the detected material that is the target compound, usually measured by HPLC as area percent. It is a ratio, so it says nothing about how many milligrams are in the vial.

Go deeper: certificate of analysis page

R

Recombinant

Chemistry and form

Recombinant describes a peptide or protein made by living cells, such as bacteria or yeast, that have been given the gene for it. It is the standard method for long chains, and it brings its own impurities, such as host cell proteins and, from bacterial hosts, endotoxin.

Go deeper: Synthetic Peptide vs Recombinant Protein

Reference standard

Testing and analysis

A reference standard is a well-characterized sample of a compound, with known identity and content, that a lab runs alongside a test sample to calibrate its measurement. Content and identity results are only as good as the standard they were measured against.

Research use only (RUO)

Regulatory

Research use only (RUO) is a labeling statement that a material is sold for laboratory research and not for use in humans or animals. The label does not settle a product’s status by itself, because the FDA looks at its intended use as a whole.

Retention time

Testing and analysis

Retention time is how long a given molecule takes to travel through the HPLC column and reach the detector. Under fixed conditions it repeats closely, which is why a sample peak can be compared against a reference standard run the same way.

Reversed-phase HPLC

Testing and analysis

Reversed-phase HPLC is the form of HPLC used for most peptides. The column surface is oily (nonpolar) and the liquid flowing through it shifts gradually from mostly water to mostly organic solvent, so molecules separate by how strongly they cling to that surface.

Go deeper: The 40-Amino-Acid Line in the FDA Protein Rule

S

Secretagogue

Chemistry and form

A secretagogue is a substance that causes a cell or gland to release (secrete) another substance. In the research literature, a growth hormone secretagogue is a compound that triggers the pituitary to release growth hormone.

Go deeper: Ipamorelin: What the Research Actually Shows

Sequence

Chemistry and form

A sequence is the order of amino acids in a peptide, written from the N-terminus (the free amino end) to the C-terminus (the carboxyl end), usually in one-letter or three-letter codes. Two peptides with the same amino acids in a different order are different compounds.

Go deeper: Synthetic Peptide vs Recombinant Protein

Sermorelin

Chemistry and form

A lab-made copy of the first 29 units of the brain’s growth hormone signal. Sermorelin is a synthetic peptide made of the first 29 amino acids of growth hormone releasing hormone (GHRH), the brain’s 44-amino-acid signal for growth hormone release.

Go deeper: Sermorelin Research: Growth Hormone Secretagogue and Pituitary Function

Solid-phase peptide synthesis

Chemistry and form

Solid-phase peptide synthesis (SPPS) is the standard chemical method for making peptides: the first amino acid is anchored to a resin bead and the chain is built one amino acid at a time. No coupling step is fully complete, so the main impurities are chains missing one or more amino acids, called deletion and truncation sequences.

Go deeper: Synthetic Peptide vs Recombinant Protein

Specification

Testing and analysis

A specification is the list of tests a material must pass, with the method for each one and the acceptance limit it has to meet. A result means more when you know the limit it was judged against.

Go deeper: The 40-Amino-Acid Line in the FDA Protein Rule

Sterility test

Testing and analysis

A sterility test checks a sample for living bacteria and fungi by placing it in growth media and watching for growth, typically over 14 days. It answers a different question from an endotoxin test, because endotoxin can remain after the bacteria that made it are dead.

T

TFA (trifluoroacetic acid)

Chemistry and form

TFA (trifluoroacetic acid) is a strong acid used to release finished peptides from the synthesis resin and in HPLC purification. Peptides purified this way are usually isolated as trifluoroacetate salts unless the counterion is exchanged afterward.

Go deeper: Synthetic Peptide vs Recombinant Protein

Third-party testing

Testing and analysis

Third-party testing is analysis by a lab independent of both the seller and the manufacturer. The phrase alone proves little, and it means something only when the lab is named and the report can be checked.

U

USP

Regulatory

The USP (United States Pharmacopeia) is an independent nonprofit that publishes official US quality standards for medicines and their ingredients, including standard test methods such as the endotoxin and sterility chapters. A test described as following a USP method was run to that published procedure.

W

Warning letter

Regulatory

A warning letter is a formal FDA notice telling a company the agency found significant violations of the law and expects them corrected. The company is usually asked to respond within 15 working days, the FDA publishes the letters on its website, and violations left uncorrected can lead to enforcement action such as seizure or injunction.

For research use only. Not for human consumption.

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