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Peptides for muscle growth

Do muscle peptides build muscle? What the trials measured

Most peptides sold for muscle get your pituitary to release more growth hormone. In trials that reliably raised growth hormone and IGF-1 in the blood. It has not been shown to make healthy people stronger. This page shows what each compound was actually tested for.

16compounds studied for muscle 4with strength measured in people 6with animal or cell data only 14prohibited in sport by WADA
See what was measured
The short version
Most muscle peptides only raise growth hormone. CJC-1295, ipamorelin, sermorelin, the GHRPs and MK-677 all work by getting the pituitary to release more growth hormone, which raises IGF-1.
Raising IGF-1 has not made healthy people stronger. MK-677 brought IGF-1 back to young-adult levels in older adults. After a year, lean mass was up 1.1 kg, mostly water, and strength had not changed.
Strength is the outcome almost nobody measured. Of the 16 compounds charted below, 8 had blood hormone levels measured in people. Only 4 had strength measured in people, and none clearly improved.
The documented side effects are real. Higher blood sugar, water retention, hunger and joint pain show up in the human studies. An MK-677 trial in hip-fracture patients stopped early over heart failure cases.
Most are banned in sport. 14 of the 16 compounds on this page are prohibited in sport by WADA, including every growth hormone secretagogue.
None was tested on top of training. No peptide here has a trial showing it adds muscle on top of resistance training in healthy adults.
How they work

What each class does to your growth hormone over 24 hours

Your body releases growth hormone in pulses, the biggest one soon after you fall asleep. Pick a class of compound to see how it changes that pattern, based on the published hormone studies.

24-hour growth hormone, modeled

Your own pattern compared with MK-677, oral

Asleep08:0012:0016:0020:0000:0004:0008:00Asleep08:0014:0020:0002:0008:00
MK-677, oralBody's own patternTaken by mouth once a day
+93%24-hour average GH vs own pattern
1.0xlow point between pulses
Samenumber of pulses (8 in own pattern)
What the hormone studies showed

Pulse height roughly doubled and the number of pulses did not change. Mean 24-hour growth hormone rose 97% in healthy older adults.

IGF-1

IGF-1 rose from 141 to 265 micrograms per liter at 4 weeks, back to young-adult levels.

What it did not show

Over 12 months lean mass rose 1.1 kg, mostly water and cell mass, with no gain in strength or function. Fasting glucose rose.

Source: Chapman 1996 and Nass 2008MK-677 (Ibutamoren)

Shapes follow the published hormone studies: when the pulse peaks, whether pulse count changes, and how much the average and the low points rise. Heights are relative, not measured units, and real responses vary a lot from person to person and fall with age.
Outcome by outcome

What the research actually measured

A rise in growth hormone is a blood test result. Muscle, strength and function are what you care about. Each cell shows whether that outcome was measured, in people or only in animals, and what happened.

What the research actually measured

Every muscle compound against every outcome that matters

↑Improved in people=No change in people~Mixed in people↓Worse in peopleAAnimal or cell onlyNever measured
CompoundGH / IGF-18 of 16 in peopleLean mass5 of 16 in peopleStrength4 of 16 in peopleFunction3 of 16 in peopleFat mass5 of 16 in peopleBlood sugar4 of 16 in people
MK-677
Tesamorelin
Sermorelin
CJC-1295
Ipamorelin
GHRP-2
GHRP-6
Hexarelin
IGF-1 LR3
PEG-MGF
SS-31
MOTS-c
SLU-PP-332
5-Amino-1MQ
NAD+
TB-500
=

MK-677: strength

No change in people. No change in strength over 12 months in healthy older adults. Source

Tap any cell for the finding and its source. "In people" counts any human measurement, positive or not. Approved uses differ: tesamorelin data come from people with HIV, SS-31 data from people with rare mitochondrial diseases.
The full list

All 16 compounds studied for muscle, ranked by evidence

Pulled live from the peptide database and sorted by evidence grade. A high grade can mean an approved drug for a different use: tesamorelin is approved for belly fat in HIV, and SS-31 for a rare genetic disease.

Ranked by strength of evidence

Every compound studied for muscle growth in this database

16 of 16 match
AApproved drug or multiple human RCTs
  1. TesamorelinGHRH analog7 human / 0 animal or cellabout 30 human studies publishedFDA-approvedWADAAn FDA-approved GHRH analog that shrinks visceral belly fat in people with HIV lipodystrophy. Not approved for weight loss.
  2. MK-677 (Ibutamoren)GH secretagogue (not a peptide)8 human / 0 animal or cellabout 25 human studies publishedIn clinical trialsWADAOral non-peptide ghrelin mimic that raises GH and IGF-1 for 24 hours. Not approved; in Phase 3 for children with GH deficiency.
  3. SS-31 (Elamipretide)Mitochondrial7 human / 1 animal or cellabout 15 human studies publishedFDA-approvedA four-amino-acid peptide that binds cardiolipin inside mitochondria. FDA-approved in 2025 as Forzinity for Barth syndrome.
BAt least one human randomized trial
  1. GHRP-2GH secretagogue7 human / 0 animal or cellabout 60 human studies publishedApproved outside USWADASynthetic ghrelin-receptor agonist. Approved in Japan only as a one-time IV test for growth hormone deficiency.
  2. SermorelinGHRH analog6 human / 0 animal or cellabout 40 human studies publishedWithdrawnWADAThe active 29-amino-acid piece of growth hormone-releasing hormone. FDA-approved for children until its maker stopped selling it in 2008.
  3. CJC-1295GHRH analog3 human / 2 animal or cellabout 3 human studies publishedResearch chemicalWADAA lab-modified version of the hormone that tells the pituitary to release growth hormone. Never approved; human data stop at dosing studies.
  4. IpamorelinGH secretagogue2 human / 3 animal or cellabout 2 human studies publishedResearch chemicalWADAA five-amino-acid ghrelin-receptor agonist that releases growth hormone. Its only efficacy trial, for post-surgery gut paralysis, failed.
CSmall or open-label human studies only
  1. HexarelinGH secretagogue6 human / 1 animal or cellabout 60 human studies publishedResearch chemicalWADAGHRP-6 analog that releases more GH than GHRP-6 or GHRH in humans and acts directly on heart muscle. Never approved anywhere.
  2. GHRP-6GH secretagogue6 human / 1 animal or cellabout 40 human studies publishedResearch chemicalWADAThe first synthetic growth hormone-releasing peptide. Triggers a short GH pulse in humans; never approved as a drug anywhere.
  3. NAD+Mitochondrial (not a peptide)7 human / 0 animal or cellabout 40 human studies publishedResearch chemicalA coenzyme every cell uses for energy and DNA repair, not a peptide. Given as IV drips and injections with very little human outcome data.
The cost side

What raising growth hormone does besides raise growth hormone

Side effects reported in the human studies, grouped. Each chip is a compound on this page whose record lists that effect.

Higher blood sugar

Growth hormone works against insulin. In the MK-677 trials fasting glucose rose and insulin sensitivity fell.

GHRP-2GHRP-6HexarelinIGF-1 LR3IpamorelinMK-677 (Ibutamoren)SermorelinTesamorelin
Water retention and swelling

Part of the "lean mass" gain on a DEXA scan is water held in tissue.

GHRP-6IGF-1 LR3IpamorelinMK-677 (Ibutamoren)SermorelinTesamorelin
Hunger

Ghrelin is the hunger hormone, and ghrelin mimics raise appetite. GHRP-2 raised buffet intake by up to a third.

GHRP-2GHRP-6MK-677 (Ibutamoren)
Cortisol and prolactin

GHRP-2, GHRP-6 and hexarelin raise stress and lactation hormones alongside growth hormone.

GHRP-2GHRP-6HexarelinMK-677 (Ibutamoren)
Joint pain and numbness

The same symptoms seen when growth hormone itself is given.

GHRP-6IGF-1 LR3IpamorelinMK-677 (Ibutamoren)SermorelinTesamorelin
Heart problems

The MK-677 hip-fracture trial stopped early after 4 heart failure cases against 1 on placebo.

CJC-1295HexarelinMK-677 (Ibutamoren)NAD+SLU-PP-332
Side by side

GHRH analogs, ghrelin mimics, MK-677 and IGF-1 analogs compared

Half-life and route come from each compound's record. The last column is the strongest result in people, which for most of them is not a muscle result.

Compound How it works Half-life Route US status Best human result
Tesamorelin GHRH analog: tells the pituitary to release GH About 11 min Subcutaneous injection FDA-approved WADA Visceral belly fat down about 15% in people with HIV
Sermorelin GHRH analog, short-acting About 4 min Subcutaneous injection Withdrawn WADA Faster growth in GH-deficient children; little change in healthy older men
CJC-1295 GHRH analog, long-acting (DAC version) About 7 days Subcutaneous injection Research chemical WADA GH and IGF-1 raised for days; no outcome measured
Ipamorelin Ghrelin mimic: one short GH pulse About 2 hours (IV, healthy men) Intravenous infusion Research chemical WADA Failed its only trial (gut recovery after surgery)
GHRP-2 Ghrelin mimic, also raises cortisol Not established Intravenous Approved outside US WADA Approved in Japan as a GH deficiency test
MK-677 (Ibutamoren) Oral ghrelin mimic, lasts all day Not established Oral In clinical trials WADA Lean mass up 1.1 kg, mostly water; no strength gain
IGF-1 LR3 Engineered IGF-1, skips the pituitary Not established Subcutaneous injection Research chemical WADA No human study of any kind
Losing weight on a GLP-1

Keeping muscle while the scale goes down

25 to 40% of the weight lost in the semaglutide and tirzepatide trials was lean mass on DEXA scans

In the DEXA substudies of STEP 1 (semaglutide) and SURMOUNT-1 (tirzepatide), lean mass made up roughly two fifths and one quarter of the weight lost. Lean mass on a scan includes water and organs, not only muscle, and the trials did not measure strength.

That number is why "peptides to keep muscle on a GLP-1" is a common search. None of the compounds on this page has a published trial testing that use.

Fat-loss trial results SURMOUNT-1 source STEP 1 source

The gaps

What the evidence does not show

Claims you will see on forums and seller pages that no published study supports.

  1. 01
    Strength gains in healthy adults

    No GH secretagogue or GHRH analog has a placebo-controlled trial showing healthy people got stronger. Source

  2. 02
    The CJC-1295 and ipamorelin stack

    The combination has never been tested as a treatment. Each drug alone has hormone data only. Source

  3. 03
    IGF-1 LR3, PEG-MGF and TB-500 in people

    None of the three has been given to a person in a published study. FDA found no human data for TB-500. Source

  4. 04
    Long-term safety of raised IGF-1

    No trial has followed people on these compounds for more than about two years. Cancer risk from years of raised IGF-1 is unstudied. Source

  5. 05
    What sold vials contain

    A black-market vial labeled IGF-1 LR3 turned out to hold a lab reagent version with an added tag, a form never meant for people. Source

  6. 06
    Muscle protection on GLP-1 drugs

    No compound on this page has a published trial showing it protects muscle during GLP-1 weight loss. Source

Keep reading

Guides and tools for reading muscle-peptide claims

The Staate peptide brief

Know when a muscle peptide finally gets a real trial

One email when a trial reads out, the FDA rules on a compounding ingredient, or WADA changes its list. Human evidence first, sources linked.
Frequently asked questions
Which peptide is best for muscle growth?
None has been shown to build muscle in healthy adults in a placebo-controlled trial. The best-studied, MK-677, raised lean mass by about 1.1 kg over a year in older adults, mostly as water and cell mass, with no change in strength. Tesamorelin, the only FDA-approved GHRH analog, is approved to reduce belly fat in people with HIV, not to build muscle.
Does CJC-1295 with ipamorelin build muscle?
There is no human evidence either way. CJC-1295 has been tested in about 63 healthy adults for hormone levels only, ipamorelin's only efficacy trial was for gut recovery after surgery and it failed, and the combination has never been studied as a treatment. Neither is FDA-approved, and both are banned by WADA.
What is the difference between a GHRH analog and a GHRP?
A GHRH analog (sermorelin, tesamorelin, CJC-1295) copies the hormone that tells the pituitary to release growth hormone. A GHRP or ghrelin mimic (ipamorelin, GHRP-2, GHRP-6, hexarelin, MK-677) acts on a separate receptor, the ghrelin receptor, which also drives hunger. Given together they release more growth hormone than either alone, which is why the pair is used as a diagnostic test.
Is MK-677 a peptide?
No. MK-677 (ibutamoren) is a small molecule taken by mouth that acts on the ghrelin receptor. It is grouped with peptides because it does the same job as the GHRPs. It is not approved for any use and is in trials only for children with growth hormone deficiency.
Is higher IGF-1 the same as more muscle?
No. Several trials raised IGF-1 a lot without changing muscle. In older women, a year of injected IGF-1 raised blood levels about fivefold with no change in lean mass, fat or strength. In older men, nightly sermorelin raised growth hormone without changing muscle on a DEXA scan.
Will these peptides fail a drug test?
Yes for competitive athletes. Growth hormone releasing factors, GHRH analogs and GH secretagogues are prohibited by WADA at all times under section S2, and unapproved compounds also fall under S0. A "research use only" label does not change that.
Sources
  1. Falutz J et al. (2007). Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med 357(23):2359-70.
  2. Ionescu M, Frohman LA (2006). Pulsatile secretion of growth hormone persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab 91(12):4792-7.
  3. Rahim A, O'Neill PA, Shalet SM (1998). Growth hormone status during long-term hexarelin therapy. J Clin Endocrinol Metab.
  4. Bowers CY et al. (1990). Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. J Clin Endocrinol Metab.
  5. Chapman IM et al. (1996). Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretogogue (MK-677) in healthy elderly subjects. J Clin Endocrinol Metab.
  6. Nass R et al. (2008). Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med.
  7. Adunsky A et al. (2011). MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study. Arch Gerontol Geriatr.
  8. Svensson J et al. (1998). Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure. J Clin Endocrinol Metab.
  9. Badran AS et al. (2026). Body composition, hepatic fat, metabolic, and safety outcomes of tesamorelin in HIV-associated lipodystrophy: a meta-analysis of randomized controlled trials. Obes Res Clin Pract 20(1):2-12.
  10. Falutz J et al. (2010). Effects of tesamorelin (TH9507) in HIV-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data. J Clin Endocrinol Metab 95(9):4291-304.
  11. Stanley TL et al. (2014). Effect of tesamorelin on visceral fat and liver fat in HIV-infected patients with abdominal fat accumulation: a randomized clinical trial. JAMA 312(4):380-9.
  12. Corpas E et al. (1992). Growth hormone-releasing hormone-(1-29) twice daily reverses the decreased GH and IGF-I levels in old men. J Clin Endocrinol Metab 75(2):530-5.
  13. Vittone J et al. (1997). Effects of single nightly injections of growth hormone-releasing hormone (GHRH 1-29) in healthy elderly men. Metabolism 46(1):89-96.
  14. Khorram O et al. (1997). Endocrine and metabolic effects of long-term administration of [Nle27]GHRH-(1-29)-NH2 in age-advanced men and women. J Clin Endocrinol Metab 82(5):1472-9.
  15. Teichman SL et al. (2006). Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab 91(3):799-805.
  16. Alba M et al. (2006). Once-daily administration of CJC-1295 normalizes growth in the GHRH knockout mouse. Am J Physiol Endocrinol Metab 291(6):E1290-4.
  17. Gobburu JV et al. (1999). Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res 16(9):1412-6.
  18. Chihara K et al. (2007). A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency. Eur J Endocrinol.
  19. Bowers CY et al. (1984). On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology.
  20. Tomas FM et al. (1996). Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection. J Endocrinol.
  21. Tomas FM et al. (1993). IGF-I and more potent variants restore growth of diabetic rats without inducing all characteristic insulin effects. Biochem J.
  22. Fornaro M et al. (2014). Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells. Am J Physiol Endocrinol Metab.
  23. Hornby B et al. (2022). Natural history comparison study to assess the efficacy of elamipretide in patients with Barth syndrome. Orphanet J Rare Dis.
  24. Karaa A et al. (2023). Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Neurology.
  25. Reynolds JC et al. (2021). MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nature Communications.
  26. Lee C et al. (2015). The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metabolism.
  27. Billon C et al. (2023). Synthetic ERR alpha/beta/gamma Agonist Induces an ERR alpha-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity. ACS Chemical Biology.
  28. Billon C et al. (2024). A Synthetic ERR Agonist Alleviates Metabolic Syndrome. Journal of Pharmacology and Experimental Therapeutics.
  29. Neelakantan H et al. (2019). Small molecule nicotinamide N-methyltransferase inhibitor activates senescent muscle stem cells and improves regenerative capacity of aged skeletal muscle. Biochemical Pharmacology.
  30. Neelakantan H et al. (2018). Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice. Biochemical Pharmacology.
  31. Babula JJ et al. (2024). Nicotinamide N-methyltransferase inhibition mitigates obesity-related metabolic dysfunction. Diabetes, Obesity and Metabolism.
  32. Prokopidis K et al. (2025). The Effect of Nicotinamide Mononucleotide and Riboside on Skeletal Muscle Mass and Function: A Systematic Review and Meta-Analysis. J Cachexia Sarcopenia Muscle.
  33. Dollerup OL et al. (2018). A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men. American Journal of Clinical Nutrition.
  34. Yoshino M et al. (2021). Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science.
  35. FDA (2024). Briefing document: CJC-1295-related bulk drug substances. Pharmacy Compounding Advisory Committee, December 4, 2024.
  36. FDA (2026). TB-500-Related Bulk Drug Substances: Briefing Document, Pharmacy Compounding Advisory Committee, July 23, 2026.
  37. Kohler M et al. (2010). Detection of His-tagged Long-R3-IGF-I in a black market product. Growth Horm IGF Res.
  38. Jastreboff AM et al. (2022). Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). NEJM.
  39. Laferrere B et al. (2006). Obese subjects respond to the stimulatory effect of the ghrelin agonist growth hormone-releasing peptide-2 on food intake. Obesity.
  40. Friedlander AL et al. (2001). One year of IGF-I treatment does not affect bone density, body composition, or psychological measures in postmenopausal women. J Clin Endocrinol Metab.
  41. NADA Germany (2025). WADA publishes Prohibited List 2026 (tirzepatide added to the 2026 Monitoring Program).

This is educational information, not medical advice. Talk to a qualified healthcare professional before changing your treatment, medication, or supplement routine, especially if you are pregnant, nursing, or managing a health condition.

Staate does not sell peptides or link to sellers. Most compounds on this page are not approved for human use. This page reports what published studies measured; it is not a recommendation to use any of them.