No human muscle outcome
Bigger muscles
Four compounds changed or tested growth hormone in people. Across all six records, no study measured muscle size or lean mass.
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Goal
Peptides for muscle growth
Sellers offer six compounds on this site for muscle growth. Not one human study of any of them measured muscle.
Source: Based on 6 compound guides · checked 2026-08-12
The six names fall into two groups. Four have been given to people and mainly show a growth-hormone signal. The other two have no human dosing study.
That distinction answers more than a ranked list can. A hormone pulse is real. Muscle size, strength, performance and training recovery are different outcomes, and none appears in these sources.
At a glance
Compounds covered
6
With published human dosing
4 of 6
Approved or being tested for this
0
No human evidence for this goal
2
Start with the outcome
What result do you mean by muscle growth?
Bigger muscles, more strength, faster recovery and better athletic performance are different outcomes. Choose the one you want to understand before comparing the studies.
No human performance outcome
More strength or athletic performance
None of the six has a human study reporting strength, power, endurance or athletic performance. A hormone reading cannot fill in those outcomes.
A different evidence question
Recovery after training or injury
The ipamorelin trials studied bowel function after surgery, not workout recovery. Injury and tissue-healing studies are covered on the recovery page.
Compare the recovery evidenceNever compared head to head
Safer than anabolic steroids
No study in these sources compares any of the six with an anabolic steroid. Sparse or missing data cannot establish a safer alternative.
Six compounds, and what each study actually measured
Read the right-hand column looking for the word muscle. It does not appear, because no study on any of these six measured it. What the studies measured was a hormone.
◆ 6 compounds coveredsources shown in each row
| Compound | What people take it for | What research shows | Evidence |
|---|---|---|---|
| Ipamorelin | Offered by clinics and sellers for muscle gain, as the cleanest of the growth-hormone peptides.Measured in a human study | It was built to raise growth hormone without the cortisol and prolactin spillover of the older compounds, and it does. Its two completed trials tested recovery of the gut after bowel surgery. Neither beat placebo, and neither weighed anybody’s muscle. | Human trialDose from a human trial · no FDA label |
| CJC-1295 | Sold for muscle, almost always stacked with ipamorelin, on the theory that two switches beat one.Measured in a human study | Two human studies exist and both measured growth hormone in the blood. One found that 60 and 90 mcg/kg did not differ from each other in effect. Most material sold under the name lacks the chemical arm that made the studied version last for days. | limited human dataDose from a human trial · no FDA label |
| Hexarelin | Pitched as the hardest-hitting of the growth-hormone peptides, for muscle and recovery.Measured in a human study | It is the one compound here dosed for a long course, and the result argues against the practice. Over 16 weeks the growth-hormone response fell from 19.1 to 10.5, then returned to 19.4 four weeks after stopping. A separate study found it raised 24-hour growth hormone without moving IGF-I at all. | limited human dataDose from a human trial · no FDA label |
| Sermorelin | Sold by wellness clinics for body composition, usually as part of a longer anti-aging package.Measured in a human study | Its largest trial ran in 110 children with growth-hormone deficiency, where height velocity rose from 4.1 to 8.0 cm/yr at six months. The one adult study ran 14 days in men of about 68, and only the 1 mg arm raised growth hormone above their own baseline. | limited human dataDose from a human trial · no FDA label |
| IGF-1 LR3 | Used on bodybuilding forums to grow muscle, usually on the back of a growth-hormone course.Reported use only | Its documented job is industrial. It is catalogued as a reagent for growing cells in tanks, where staying active is the selling point. No study of it in people has ever been registered. The change that makes it useful in a tank removes the body’s own brake on the signal. | no human dose shown to workDose reported in the literature only |
| PEG-MGF | Sold for muscle repair and growth after training, as a finisher to a growth-hormone course.Reported use only | Nobody has given it to a person in a study. The human research here takes muscle biopsies and measures what the body makes on its own, and even that work disagrees about whether training raises it. The peptide itself has only been put on cultured cells and mice. | no human dose shown to workDose reported in the literature only |
A hormone pulse is a mechanism, not a result
Four of these six have human pharmacology data. Researchers dosed volunteers, drew blood and measured a rise in growth hormone. That evidence is real, but it is not the same as proof of muscle growth.
What none of it does is close the loop. Between a hormone pulse and a bigger muscle sit sleep, food, training, IGF-I and time. The one study here that looked at IGF-I found hexarelin did not move it. A mechanism that fires is a reason to run the trial. It is not the trial.
Hexarelin also supplies the one long-course result on this page, and it points the wrong way for anyone dosing for months. The response nearly halved by week 16 and recovered only after stopping. Nobody turned that into a schedule, because nobody ran the study that would have to.
What would have to be measured
A trial that answered this question would run for months. It would feed and train everyone the same way, then measure lean mass against a placebo group. No such trial appears on any of these six records.
Nobody has given two of the six to a person in a registered study. Research on IGF-1 LR3 and PEG-MGF is limited to cells, animals and muscle samples from people who were not given either peptide.
Where to go next
Why no page here ranks anything
What PEG-MGF is, how it is used, and what has been studied
How hexarelin differs from the rest of its class
How IGF-1 LR3 differs from the rest of its class
Testosterone: the page beside the pitch
Which skin claims have a trial
How ipamorelin differs from the rest of its class
How CJC-1295 differs from the rest of its class
Questions readers ask
Which peptides are best for muscle growth?
Are peptides safer than steroids?
What are the downsides of taking peptides?
Do peptides really work for muscle building?
- Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. 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 2006;91(3):799-805retrieved 2026-08-12Human trial
- Ionescu M, Frohman LA. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. J Clin Endocrinol Metab 2006;91(12):4792-7retrieved 2026-08-12Human trial
- Dominikowski A, Rękoś Z, Olejarz M, Szczepanek-Parulska E, Domin R, Ruchała M. The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol 2026 — tabulates self-reported online dosing patterns beside the clinical doses, stating the reported values must not be read as clinically validated, regulatory-approved or saferetrieved 2026-08-12indirect evidence
- NCT01280344 — Phase II double-blind placebo-controlled dose-finding study of ipamorelin for recovery of gastrointestinal function after small or large bowel resection (Helsinn Therapeutics; 320 patients; arms 0.03 mg/kg BID, 0.06 mg/kg BID, 0.06 mg/kg TID, all intravenous)retrieved 2026-08-12Human trial
- Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis 2014;29(12):1527-34retrieved 2026-08-12Human trial
- Thorner M, et al. Once daily subcutaneous growth hormone-releasing hormone therapy accelerates growth in growth hormone-deficient children during the first year of therapy (Geref International Study Group). J Clin Endocrinol Metab 1996;81(3):1189-96retrieved 2026-08-12Human trial
- Corpas E, Harman SM, Piñeyro MA, Roberson R, Blackman MR. Growth hormone (GH)-releasing hormone-(1-29) twice daily reverses the decreased GH and insulin-like growth factor-I levels in old men. J Clin Endocrinol Metab 1992;75(2):530-5retrieved 2026-08-12Human trial
- NCT00324064 — Sexually Dimorphic Effects of GHRH in Adult Growth Hormone Testing (protocol: GHRH [Geref] 1 mcg/kg intravenous push, followed by arginine)retrieved 2026-08-12Human trial
- Rahim A, O’Neill PA, Shalet SM. Growth hormone status during long-term hexarelin therapy. J Clin Endocrinol Metab 1998;83(5):1644-9retrieved 2026-08-12Human trial
- Maccario M, Veldhuis JD, Broglio F, Di Vito L, Arvat E, Deghenghi R, Ghigo E. Impact of two or three daily subcutaneous injections of hexarelin, a synthetic growth hormone (GH) secretagogue, on 24-h GH, prolactin, adrenocorticotropin and cortisol secretion in humans. Eur J Endocrinol 2002;146(3):310-8retrieved 2026-08-12Human trial
- Massoud AF, Hindmarsh PC, Brook CG. Hexarelin-induced growth hormone, cortisol, and prolactin release: a dose-response study. J Clin Endocrinol Metab 1996;81(12):4338-41retrieved 2026-08-12Human trial