Peptides.media

Use case

Muscle growth

Which peptides have credible human evidence for muscle growth?

Context

Muscle-growth claims sit next to training, nutrition, sleep, and approved therapies for specific wasting diseases; none of the compounds discussed online is an approved hypertrophy drug.

Compare IGF-1 variants, follistatins, ACE-031, and GH secretagogues around hypertrophy claims: a category where mechanism is strong and controlled human outcome data are nearly absent.

Peptides compared

Evidence unclear

IGF-1 LR3

IGF-1 LR3 is a long-acting modified IGF-1 analog sold for muscle growth. The modification that makes it popular has no human clinical literature, and the pharmacology carries real hypoglycemia risk.

Not FDA-approved for listed uses
Evidence unclear

IGF-1 DES

IGF-1 DES is a shortened, more potent IGF-1 variant discussed for localized muscle growth. It shares the same absence of human evidence and the same hypoglycemia mechanism risk as IGF-1 LR3.

Not FDA-approved for listed uses
Mostly preclinical

Follistatin-344

Follistatin-344 is a myostatin-binding protein isoform discussed for muscle growth. Animal myostatin-pathway data are real, but there are no human trials of injected follistatin for physique purposes.

Not FDA-approved for listed uses
Limited human evidence

ACE-031

ACE-031 is a soluble activin receptor that reached human trials for muscular dystrophy before development stopped after vascular adverse events. It remains a cautionary example of mechanism-first muscle claims.

Investigational / not approved
Limited human evidence

GHRP-2

GHRP-2 (pralmorelin) is a growth-hormone secretagogue with real human physiology literature and approval in Japan as a diagnostic agent. Broader muscle, recovery, and anti-aging claims are extrapolations from its hormone effect.

Varies by product and jurisdiction
Limited human evidence

Hexarelin

Hexarelin is the most potent common GHRP-class secretagogue, with human endocrine challenge literature but no outcome trials. Community use is limited by desensitization concerns and the class's strongest cortisol and prolactin spillover.

Not FDA-approved for listed uses

Sources

  1. 1.

    FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks 2026.

    Accessed 2026-06-08.

    FDA summarizes potential significant safety risks and missing safety information for several nominated peptide bulk substances.