Peptides for Muscle Wasting — Evidence Review
Muscle wasting — sarcopenia of aging, cachexia in cancer or chronic illness, post-injury atrophy — is distinct from "muscle building" in healthy adults. The therapeutic priorities differ: lean-mass…
Muscle wasting — sarcopenia of aging, cachexia in cancer or chronic illness, post-injury atrophy — is distinct from "muscle building" in healthy adults. The therapeutic priorities differ: lean-mass preservation matters more than performance enhancement, and safety profiles must account for compromised baseline health.
Important context: GLP-1 agonists (tirzepatide, semaglutide) cause meaningful lean-mass loss alongside fat loss in obesity treatment. They are contraindicated as muscle-preservation therapy in already-sarcopenic patients.
Peptides with the most relevant evidence
Tesamorelin
GHRH analog with FDA approval for HIV-associated lipodystrophy. Increases endogenous GH and IGF-1, with reported lean-mass preservation and visceral-fat reduction. Several studies in HIV cohorts show favorable body-composition changes that include lean-mass effects, not only fat loss.
In non-HIV sarcopenia, off-label use is limited; long-term outcomes data does not yet exist. The mechanism (endogenous GH stimulation) is more conservative than direct exogenous GH or IGF-1 administration.
IGF-1 LR3
Insulin-like growth factor 1 with extended pharmacokinetics. Animal models and small human studies show muscle-anabolic effects, but cancer-relevant safety concerns are substantial — IGF-1 elevation correlates with several cancer incidence patterns. WADA prohibited substance.
For muscle wasting in non-cancer contexts, the conservative case is endogenous-stimulation peptides (tesamorelin, sermorelin) rather than direct IGF-1 administration.
MGF (Mechano Growth Factor)
IGF-1 splice variant produced in muscle in response to mechanical loading. Animal studies show muscle repair and growth in injury models. Human data is preliminary; the mechanistic case for post-injury atrophy is more developed than for chronic sarcopenia.
Sermorelin
GHRH analog (shorter-acting than tesamorelin). Clinical use for adult GH deficiency. May have a modest place in age-related GH decline; magnitude of effect on body composition is smaller than direct GH replacement.
Supporting cast
MK-677 (Ibutamoren)
Orally active GH secretagogue. Increases GH and IGF-1; has been studied in age-related sarcopenia. Side effects include water retention and modest insulin resistance — relevant for older patients with metabolic comorbidities.
CJC-1295 + Ipamorelin
GH-secretagogue stack used in research-protocol contexts for body-composition support. The pulsatile GH-elevation pattern has theoretical advantages over sustained GH replacement; clinical data in true sarcopenia is limited.
Full CJC-1295 profile → | Full ipamorelin profile →
What the evidence does not support
- GLP-1 agonists for muscle preservation — they cause lean-mass loss
- BPC-157 or TB-500 as primary muscle-wasting therapy — these address tissue repair, not anabolic-anticatabolic balance
- Peptides as a substitute for resistance training (the strongest single intervention for sarcopenia)
- Peptide use in cancer cachexia without oncology oversight — anabolic action and pro-angiogenic effects intersect with cancer biology in complex ways
Where to source
- Tesamorelin vendor rankings — limited; tesamorelin compounding is regulatorily restricted
- Ipamorelin vendor rankings — 19 ranked vendors
- CJC-1295 vendor rankings — data still aggregating
What we don't know
- Whether tesamorelin produces sarcopenia-relevant outcomes in non-HIV elderly populations
- Whether IGF-1 LR3 can be safely used long-term outside athletic-doping contexts
- Optimal sequencing of peptide therapy with resistance training and protein optimization
- Cancer-related safety in elderly patients on long-term GH-elevating peptides
Methodology
Read the full methodology.
This page is educational. Sarcopenia and cachexia management requires medical oversight — geriatric, internal medicine, or oncology depending on the underlying cause. Resistance training, adequate protein, and treatment of the underlying disease are first-line.