Claimed effect · IGF-1 LR3

Does IGF-1 LR3 help with muscle growth?

D
Grade D — no human evidence0 controlled · effect size: not measurable
Short answerNo human evidence. As of 3 September 2026, no controlled human trial has tested IGF-1 LR3 for muscle growth. No controlled human trial of IGF-1 LR3 exists for muscle, strength or body composition. The claims extrapolate from IGF-1's known role in tissue growth and from animal and cell work.

What the studies show

No controlled human trial of IGF-1 LR3 exists for muscle, strength or body composition. The claims extrapolate from IGF-1's known role in tissue growth and from animal and cell work.

Animal studies, cell studies, or anecdotes only. This is where almost every viral peptide sits. Promising and proven are different words for a reason.

In context

IGF-1 LR3 is a modified version of insulin-like growth factor 1, engineered so that it evades the binding proteins that normally control IGF-1 and therefore stays active far longer. It was designed as a cell-culture reagent for laboratories, not as a medicine, and no controlled human trial has ever tested it. Natural IGF-1 is available as an approved drug, mecasermin, for a rare severe deficiency — the LR3 analogue is a different molecule with no clinical file at all.

IGF-1 LR3 is not approved; research reagent. Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is IGF-1 LR3 proven to help with muscle growth?
No. There is no human evidence for it (0 controlled); the claim rests on animal or cell studies and LYO grades it D.
What studies are behind the grade?
No controlled human trial of IGF-1 LR3 exists for muscle, strength or body composition. The claims extrapolate from IGF-1's known role in tissue growth and from animal and cell work.
Is IGF-1 LR3 approved for this?
No. IGF-1 LR3 is not approved; research reagent; it is not an approved medicine for any indication in the jurisdictions LYO covers.

Other outcomes for IGF-1 LR3

Written and maintained by LYO Research — how pages are written and checked. Reviewed 3 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →