Last updated 10 October 2026 · SARMs Store editorial team. Products on this site are supplied strictly for laboratory research and are not for human consumption. This guide summarises published research; it is not medical advice and contains no instructions for use. 18+ only.
"Peptides for muscle growth" is one of the most searched phrases in this market, and the honest answer is shorter than most pages that rank for it. No peptide in the research supply market is licensed for building muscle, and none has a controlled human trial showing that it builds muscle in healthy people. What does exist is two separate bodies of research that often get blended together: human studies of peptides that raise growth hormone, and animal studies of peptides that speed up the healing of injured muscle, tendon and other tissue. This guide sets out what each one actually measured.
The evidence at a glance
| Peptide | How it is thought to work | Highest evidence | What was measured | WADA |
|---|---|---|---|---|
| BPC-157 | Gastric peptide fragment; blood vessel growth in healing tissue | Rodent studies | Healing of crushed and cut muscle, tendon and ligament in rats | S0 |
| TB-500 | Fragment of thymosin beta-4; binds actin, drives cell migration | Full protein: phase II wound trials. Fragment: animal studies | Wound closure, cardiac repair in mice | S2 |
| CJC-1295 | Long-acting GHRH analogue | Phase I and II pharmacology | Growth hormone and IGF-1 levels | S2 |
| Ipamorelin | Ghrelin receptor agonist | Phase I; phase II in gut paralysis after surgery, stopped | Growth hormone release | S2 |
| Sermorelin | First 29 amino acids of GHRH | Former US licence in children; small adult studies | Growth hormone, IGF-1, small body composition changes | S2 |
| Tesamorelin | Stabilised GHRH analogue | Two phase III trials; US approval 2010 for one indication | Visceral fat in people with HIV | S2 |
| GHK-Cu | Copper tripeptide; collagen synthesis in cell culture | Small topical human studies | Skin and wound healing | Not named; may fall under S2 |
Two different questions: growth and repair
The first group, the growth hormone peptides, are studied for what they do to a hormone. CJC-1295, sermorelin and tesamorelin mimic growth hormone releasing hormone; ipamorelin mimics ghrelin. All four make the pituitary release more of its own growth hormone, which in turn raises IGF-1. The research question is whether that hormonal change alters body composition.
The second group, the tissue repair peptides, are studied for what they do to an injury. BPC-157 and TB-500 have been tested in animals with cut, crushed or detached muscle and tendon, and the outcome is how quickly and how completely the tissue heals. That is a different question from whether healthy muscle grows, and the two should not be read across.
Growth hormone peptides: raising a hormone is not building muscle
The best guide to what growth hormone peptides could do is what growth hormone itself does, because that has been studied directly and pooled in two systematic reviews.
In young, fit adults. Liu and colleagues, in Annals of Internal Medicine in 2008, pooled 27 randomised study samples in which 303 healthy, physically fit people aged 13 to 45 received growth hormone. Lean body mass rose by 2.1 kg compared with controls, but strength and exercise capacity did not appear to improve, and the treated groups had more fluid retention and fatigue. The authors concluded that claims of better physical performance are not supported. Lean body mass includes water, and part of the gain in short studies is likely to be fluid rather than muscle.
In healthy older adults. A 2007 review by the same group in the same journal pooled 18 study populations with a mean age of 69. Lean body mass rose by 2.1 kg and fat mass fell by 2.1 kg, with no change in body weight, but the treated groups had more fluid retention, joint pain, carpal tunnel syndrome and breast tissue growth, and were somewhat more likely to develop diabetes or raised fasting glucose. The authors concluded that growth hormone could not be recommended as an anti-ageing therapy.
What the secretagogues add. The peptides sold for research raise growth hormone indirectly, and their human data is mostly about the hormone itself. Teichman and colleagues (Journal of Clinical Endocrinology and Metabolism, 2006) showed that single injections of CJC-1295 raised growth hormone two to tenfold and IGF-1 1.5 to threefold for six days or more in healthy adults, but no efficacy trial followed. Small 1990s studies of sermorelin in older men, from the US National Institute on Aging, reported raised IGF-1 and small increases in lean mass in groups of 10 to 20 people. Ipamorelin has no body composition trial at all.
The largest trials are about fat, not muscle. Tesamorelin is the only peptide here that reached phase III. Falutz and colleagues (New England Journal of Medicine, 2007) randomised 412 people with HIV and excess abdominal fat to tesamorelin or placebo for 26 weeks. Visceral fat fell by 15.2 per cent with tesamorelin and rose by 5.0 per cent with placebo, and IGF-1 rose by 81 per cent. That supported US approval in 2010 for that single use. It is a fat distribution result in a defined patient group, not a muscle result.
The closest comparison is not a peptide. MK-677, an oral growth hormone secretagogue acting on the same receptor as ipamorelin, has the longest human record in this space. In a two-year trial in 65 healthy adults aged 60 to 81 (Nass and colleagues, Annals of Internal Medicine, 2008), fat-free mass rose by 1.1 kg over a year with MK-677 and fell by 0.5 kg with placebo. Body weight rose by 2.7 kg, fasting glucose rose and insulin sensitivity fell, and the authors noted the study was not large or long enough to assess function. See the MK-677 guide.
Taken together, raising growth hormone produces small changes in measured lean mass, a meaningful share of which may be water, with no demonstrated gain in strength and a consistent signal of raised blood glucose. No growth hormone peptide has been shown to do more than that in people.
Tissue repair peptides: muscle healing in rats
BPC-157. The muscle work is a series of rat injury studies from the University of Zagreb. Pevec and colleagues (Medical Science Monitor, 2010) crushed the gastrocnemius muscle complex in rats and reported faster healing and restored function with BPC-157, given by injection or as a local cream, including in animals whose healing had been impaired by a corticosteroid. Brcic and colleagues (Journal of Physiology and Pharmacology, 2009) linked the effect to increased VEGF expression and blood vessel growth in healing muscle and tendon, while finding no direct effect on blood vessel cells in culture. Later studies from the same group tested detached quadriceps and damaged muscle tendon junctions in rats. A 2019 review in Cell and Tissue Research (Gwyer, Wragg and Wilson) called the musculoskeletal findings consistent but noted that almost all of them come from one laboratory and that human trials are needed.
TB-500. Thymosin beta-4, the protein TB-500 is taken from, regulates actin, the scaffold that lets cells move into a wound. The full protein has been through phase II trials as a gel for skin ulcers and as eye drops, and improved heart repair in mice after a heart attack (Bock-Marquette and colleagues, Nature, 2004). There is no muscle growth trial, and no human trial of the fragment sold as TB-500.
The blends. The Wolverine blend combines BPC-157 and TB-500. No published study has tested the two together, so the rationale rests on their separate animal records.
GHK-Cu. In fibroblast cultures GHK-Cu stimulated collagen and other components of connective tissue (Maquart and colleagues, FEBS Letters, 1988), and small topical human studies report effects on skin and wound healing. There is no injected human trial and no muscle study.
What is missing
Across the whole category: no controlled human trial of any research peptide for muscle growth in healthy people, no trial comparing one peptide with another, no trial of any blend, and for BPC-157 almost no independent replication outside the group that discovered it. Anything a buyer reads about a peptide building muscle in a person is anecdote or extrapolation from a different molecule.
Peptides compared with SARMs on muscle evidence
On the specific question of muscle mass, the SARMs have more human data than the peptides. Ostarine reached phase III trials with lean mass as an endpoint, and LGD-4033 has phase I and phase II lean mass data, though neither became a licensed medicine and both suppress natural testosterone. The peptides' strengths are elsewhere: hormone pharmacology for the secretagogues and tissue repair models for BPC-157 and TB-500. Our SARMs vs peptides guide compares the two classes on mechanism, evidence and storage, and Best SARMs UK ranks the SARMs by clinical record.
Legal status in the UK, 2026
None of these peptides is controlled under the Misuse of Drugs Act 1971. None holds a UK marketing authorisation, so under the Human Medicines Regulations 2012 none can lawfully be sold or advertised for human use, and the MHRA treats products supplied with human dosing instructions or health claims as unlicensed medicines. Tesamorelin is licensed in the United States for one indication but not in the UK or EU. In sport, BPC-157 falls under WADA section S0 and the growth hormone peptides and TB-500 under section S2, all prohibited at all times; anyone subject to testing should treat GHK-Cu as prohibited too.
What to check before buying
Milligram content per vial, HPLC purity, mass spectrometry identity and a batch number that matches the certificate. Lyophilised peptides need cold storage and, for laboratory work, reconstitution in a suitable diluent; see the bacteriostatic water guide. Every Origin Peptides batch is independently tested and its certificate of analysis is published on the product page and the Lab Testing page.
Frequently asked questions
Do peptides build muscle? No peptide has been shown to build muscle in healthy people in a controlled trial. Growth hormone peptides raise growth hormone and IGF-1, and growth hormone itself adds a small amount of lean mass, part of it water, without improving strength.
Which peptide has the most human research? Tesamorelin, with two phase III trials, but they measured visceral fat in people with HIV, not muscle.
Has BPC-157 been studied for muscle injury? Yes, in rats. Studies from the University of Zagreb report faster healing of crushed and cut muscle, but there is no human muscle trial.
Is TB-500 the same as thymosin beta-4? No. TB-500 is a short synthetic fragment of the 43 amino acid protein. The human trials tested the full protein.
Are peptides or SARMs better studied for muscle mass? SARMs. Ostarine reached phase III with lean mass as an endpoint; no research peptide has a muscle growth trial.
Are muscle research peptides banned in sport? Yes. BPC-157 is prohibited under WADA S0, and TB-500 and the growth hormone peptides under S2, at all times.
Related reading
- BPC-157: what the studies show
- TB-500 research guide
- CJC-1295 and Ipamorelin research guide
- Tesamorelin research guide
- SARMs vs peptides
Research products: Origin Peptides BPC-157 · TB-500 · CJC-1295 + Ipamorelin 10mg · Sermorelin 5mg · Tesamorelin 10mg · Full Origin Peptides range
Sources: Maquart FX et al., FEBS Lett 1988;238:343-346. Bock-Marquette I et al., Nature 2004;432:466-472. Teichman SL et al., J Clin Endocrinol Metab 2006;91:799-805. Liu H et al., Ann Intern Med 2007;146:104-115. Falutz J et al., N Engl J Med 2007;357:2359-2370. Liu H et al., Ann Intern Med 2008;148:747-758. Nass R et al., Ann Intern Med 2008;149:601-611. Brcic L et al., J Physiol Pharmacol 2009;60 Suppl 7:191-196. Pevec D et al., Med Sci Monit 2010;16:BR81-88. Gwyer D, Wragg NM, Wilson SL, Cell Tissue Res 2019;377:153-159. WADA Prohibited List 2026, sections S0 and S2.