Best Growth Hormone Peptides and Secretagogues: Evidence Compared (2026)

Short answer: tesamorelin has the best evidence, MK-677 the most trials, and none is proven to build muscle in healthy people. Growth hormone peptides and secretagogues make the pituitary release more of your own GH, which raises IGF-1. They work through two routes: GHRH analogs (tesamorelin, CJC-1295, sermorelin) and ghrelin-receptor drugs (MK-677, ipamorelin). Only tesamorelin is a currently approved medicine, for deep belly fat in adults with HIV. Below they are ranked by human evidence.

GH peptides compared

Scores run from 0 (none) to 3 (high); see our methodology. Data from the SARMs database.

1. Tesamorelin: the only approved option

Tesamorelin is a GHRH analog approved by the FDA in 2010 (Egrifta) to reduce excess abdominal fat in adults with HIV-associated lipodystrophy. In a 26-week trial in 412 adults, visceral fat fell 15.2% vs a 5.0% rise on placebo, triglycerides fell and IGF-1 rose 81%; weight did not change and the fat came back after stopping. Its label lists injection-site reactions (25%), joint pain and swelling, higher blood sugar and IGF-1 above normal in nearly half of patients. It has not been tested for muscle in healthy adults.

2. MK-677: the most studied, and taken by mouth

MK-677 (ibutamoren) is a non-peptide ghrelin mimetic. In 17 trials, including 12 months in healthy older adults, 25 mg/day raised GH 1.8-fold and IGF-1 1.5-fold and added 1.1 kg of fat-free mass (vs a 0.5 kg loss on placebo), without improving strength. Appetite, water retention, muscle pain and higher fasting glucose were common, and a hip-fracture trial in frail older adults was stopped over heart failure. It is in Phase 3 (as LUM-201) for children with GH deficiency, and not approved anywhere.

3. CJC-1295: long-acting GHRH analog

CJC-1295 with DAC binds albumin and lasts about a week: in small 2006 studies, one injection raised GH 2–10-fold for 6 days or more and IGF-1 1.5–3-fold for 9–11 days. Its Phase 2 trial was terminated, and the FDA cites serious adverse events, including faster heart rate and a vasodilatory reaction. The “without DAC” form sold today has no published human data.

4. Sermorelin: the old approved GHRH

Sermorelin (GHRH 1-29) was approved in 1997 as Geref for children with GH deficiency and later discontinued, for reasons the FDA found were not about safety or effectiveness. In 11 healthy older men, 6 weeks of nightly injections raised night-time GH but not IGF-1, and body composition did not change.

5. Ipamorelin: selective, but little human data

Ipamorelin is a five-amino-acid ghrelin-receptor peptide that, in pigs, raised GH without raising cortisol or prolactin. In people it has one pharmacokinetic study (a short GH pulse, half-life about 2 hours) and a surgery trial that found no benefit. The FDA lists it in Category 2 (significant safety risks) for outsourcing facilities.

What about GHRP-2, GHRP-6 and hexarelin?

These older growth hormone-releasing peptides act on the same ghrelin receptor as ipamorelin and MK-677. They are not in our database yet; like ipamorelin, they are banned in sport under WADA S2.2.4 and have no trials showing muscle or fat benefits in healthy adults. See our hexarelin guide.

GH peptides vs real growth hormone

These drugs raise your own GH within the body’s feedback limits, so GH and IGF-1 rise less than with injected HGH, and their effects are milder. In children with GH deficiency, MK-677 (as LUM-201) raised growth rate less than injected GH did. See MK-677 vs HGH.

Risks they share

• Higher IGF-1: the point of these drugs, but long-term effects of keeping it raised are unknown; caution is usually advised with any current or past cancer.
• Blood sugar: MK-677 and tesamorelin both raised glucose or HbA1c in trials.
• Fluid: swelling, joint pain and carpal tunnel symptoms.
• Product quality: the FDA flags impurities and immune reactions with research peptides.
• Sport: all are prohibited at all times under WADA S2.2.4.

Verdict

If the question is which GH peptide has real evidence, it is tesamorelin, for a specific medical use. If it is which one has been studied most, MK-677, with well-documented downsides. CJC-1295, sermorelin and ipamorelin raise GH in small studies but have no proven body-composition benefit. For combinations and comparisons, see tesamorelin vs ipamorelin, MK-677 vs ipamorelin and CJC-1295 vs ipamorelin.