Acknowledgements This work was supported by the National Key Research and Development Program of China 202lYFA1000200 and 2021YFA1000203 (YL
This content is not authored by medical professionals, and it does not offer medical guidance
Reported benefits (per available research): Studied in cell-culture and animal muscle models for activating satellite cells and stimulating both muscle-fiber hypertrophy and hyperplasia (an increase in fiber number), effects attributed to sustained IGF-1 receptor activation rather than direct human testing Explored in preclinical rodent studies of tendon, ligament, and other connective-tissue injury, where researchers report IGF-1 pathway activation appeared to support markers of tissue repair and collagen synthesis Proposed by some peptide researchers to support faster recovery from training-induced muscle stress, based on IGF-1's known role in protein synthesis and cell-survival signaling (PI3K/Akt pathway), though this has not been confirmed in controlled human trials of IGF-1 LR3 itself Known risks and side effects: Hypoglycemia: because the IGF-1 receptor pathway overlaps with insulin signaling, activation can lower blood glucose, with reported effects ranging from shakiness and confusion to, in severe cases, seizure or loss of consciousness Organomegaly and acromegaly-like changes: sustained elevation of IGF-1 signaling has been linked in the broader IGF-1/growth-hormone literature to enlargement of the jaw, hands, feet, heart, and other organs with prolonged exposure Theoretical tumor-growth risk: IGF-1 receptor signaling promotes cell proliferation and inhibits programmed cell death, so researchers have raised concern that elevated IGF-1 activity could theoretically support growth of existing malignant or precancerous cells, though this risk has not been directly established for IGF-1 LR3 in humans Injection-site reactions and an absence of human safety data: no controlled human trials have evaluated IGF-1 LR3's safety, purity, or contamination risk, so dosing accuracy, product quality, and long-term effects in bodybuilding-style use remain unverified Evidence snapshot: No published human clinical trials of IGF-1 LR3 exist
Haddad M, Stewart J, Xie P, et al
