Muscle & body comp.
Strongest evidence sits at the boundary with body composition (lean preservation under caloric deficit). Pure hypertrophy evidence in healthy adults is limited.
How this class moves the outcome.
Pulsatile GH release (GHRH analogues)
Sermorelin / tesamorelin / CJC-1295 mimic endogenous GHRH, amplifying physiological GH pulses rather than replacing them.
Ghrelin receptor agonism
Ipamorelin and MK-677 act on the GH secretagogue receptor; MK-677 is orally bioavailable and elevates IGF-1 chronically.
Lean-mass preservation under caloric deficit
Combined with sufficient protein and resistance training, the class can attenuate fat-free-mass loss during weight reduction.
Ranked by human-evidence strength.
- 01
Ipamorelin
Selective GH secretagogue with minimal effect on cortisol or prolactin. Reported for sleep and recovery.
Growth hormone secretagoguet½ ~2 hPreclinical only - 02
CJC-1295 (with DAC)
DAC:GRFGHRH analogue with drug-affinity complex extending half-life to days. Sustained elevation of GH/IGF-1.
GHRH analogue (long-acting)t½ ~6–8 daysPreclinical only - 03
Sermorelin
GRF 1-29Synthetic GHRH(1-29) historically marketed as Geref. Common in US anti-aging compounding.
GHRH analoguet½ ~10–20 minHuman RCT - 04
Tesamorelin
EgriftaStabilised GHRH analogue approved for HIV-associated lipodystrophy; reduces visceral adipose tissue.
GHRH analogue (stabilised)t½ ~26–38 minHuman RCT - 05
MK-677
IbutamorenOrally active non-peptide ghrelin mimetic. Sustained GH/IGF-1 elevation but increases appetite and water retention.
Oral ghrelin mimetict½ ~4–6 hHuman RCT
What the human data actually shows.
Each bar is the proportion of candidates on this brief at that evidence tier. RCT first, observational second, preclinical and anecdotal labeled and never inflated.
See full methodology →Indexed human trials and reviews driving the candidate rankings above. Sorted by study type, then recency.
- moderateFalutz J, Mamputu JC, Potvin D, et al.
Tesamorelin 2 mg SC daily over 52 weeks sustained VAT reduction and lean body mass preservation/modest gain vs placebo.
RCTn=8162010unreviewed - moderateNass R, Pezzoli SS, Oliveri MC, et al.
MK-677 25 mg orally daily for 12 months increased fat-free mass by ~1.1 kg vs placebo; raised IGF-1; increased appetite/weight; transient fasting glucose elevation.
RCTn=652008unreviewed - strongFalutz J, Allas S, Blot K, et al.
Tesamorelin elevated IGF-1 within physiologic range over 26 weeks vs placebo.
RCTn=4122007unreviewed - moderateChapman IM, Bach MA, Van Cauter E, et al.
MK-677 25 mg orally once daily for up to 4 weeks restored serum IGF-1 in older adults to levels of young adults; raised mean 24h GH.
RCTn=321996unreviewed - moderateThorner M, Rochiccioli P, Colle M, et al.
Sermorelin 30 mcg/kg SC at bedtime for 12 months increased growth velocity in GH-deficient children; rise in IGF-1.
Observationaln=1101996unreviewed
Where this class can hurt you.
- Chronic IGF-1 elevation has theoretical cancer-progression risk and is contraindicated in active malignancy.
- Insulin sensitivity can degrade with sustained GH-axis elevation.
- Most published data is in deficiency or sarcopenia populations, not healthy athletes.
- Most clinical data is in deficiency or sarcopenia populations, not healthy athletes.
- Hypertrophy outcomes are confounded by training, sleep, and protein intake.
Decide between candidates.
Put the top 4 candidates side by side.
Mechanism · half-life · routes · evidence tier · safety signals. A decision matrix, not a leaderboard.
Current scientific consensus.
- Tesamorelin for visceral adiposity
- IGF-1 elevation (mechanism)
- Hypertrophy in trained healthy adults
- Long-term cancer-risk signal with chronic use
- Optimal cycling pattern
"Real wins in clinical populations. In healthy trained adults, training and nutrition still dominate the outcome."
Where this is heading.
Real wins in clinical populations. In healthy trained adults, training and nutrition still dominate the outcome.
We re-grade this brief quarterly. Confidence and outcome grades shift as new RCTs publish, safety data accumulates, and replication efforts read out. Changes are logged publicly on the evidence changelog.
Matched protocol templates.
Matching templates…