Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of Follistatin 344 and IGF-1 LR3 — mechanism, side effects, legal status, and pricing.
Follistatin 344 is a recombinant form of the naturally-occurring glycoprotein (344-residue splice variant) that inhibits activin and myostatin signaling. Clinical validation exists ONLY through small AAV gene-therapy phase 1/2 trials in Becker muscular dystrophy; recombinant injectable protein sold on the grey market has no clinical evidence. NOT FDA-approved. WADA-prohibited (myostatin inhibitor) and banned in competitive sport.
IGF-1 LR3 is an 83-amino-acid modified IGF-1 analog with a 13-residue N-terminal extension (MFPAMPLSSLFVN) and an Arg-3 substitution. These modifications reduce binding to IGF binding proteins (IGFBPs), extending effective half-life and increasing tissue bioavailability relative to native IGF-1. It is a research/cell-culture reagent and is NOT FDA-approved for any human use. Do not confuse with mecasermin (Increlex), which is recombinant human IGF-1 and IS FDA-approved for severe primary IGF-1 deficiency.
Follistatin 344
IGF-1 LR3
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
Follistatin 344
IGF-1 LR3
COA corpus from Disclosed Labs — independently tested batches only.
Follistatin 344
2
COAs
99.5%
Avg purity
2
Labs
IGF-1 LR3
42
COAs
98.7%
Avg purity
9
Labs
AAV1-FS344 intramuscular gene therapy Phase 1/2a in Becker muscular dystrophy (n=6) reported improved 6-minute walk test and quadriceps volume changes (Mendell et al., Molecular Therapy, 2015). Preclinical mdx mouse and cynomolgus primate studies showed durable muscle mass and strength increases (Kota et al., Science Translational Medicine, 2009). Recombinant Follistatin-344 protein sold as an injectable research chemical has NO validated human clinical data — all positive human evidence is from AAV gene therapy, not peripheral protein injection. Not FDA-approved. WADA-prohibited at all times.
Francis et al. (J Mol Endocrinol 1992; PMID 1378742) characterized LR3-IGF-1 as a fusion analog whose enhanced biological potency derives from reduced IGFBP binding; in IGFBP-free cell systems LR3 was actually LESS potent than native IGF-1, underscoring that the 'potency' is really reduced sequestration rather than intrinsically stronger receptor activation. Tomas (Growth Horm IGF Res 2001; PMID 11472075) infused LR(3)IGF-I into food-restricted rats and found it preserved body weight and nitrogen retention but did NOT conserve skeletal muscle protein — which contradicts the common 'potent muscle builder' framing from preclinical literature alone. There are no controlled human trials supporting bodybuilding use. Epidemiologic and mechanistic work reviewed by Grimberg (Cancer Biol Ther 2003; PMID 14688466) links elevated IGF-1 axis activity to breast, prostate, and colorectal cancer risk, so chronic systemic LR3 exposure carries a concrete — not merely theoretical — tumorigenesis concern. IGF-1 and its analogs are banned at all times under the WADA Code.
Follistatin 344 and IGF-1 LR3 are both in the Performance category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Disclosed Labs