Mecasermin (rhIGF-1)
Aliases: Increlex
Last verified: 2026-09-23
The short version
Recombinant human IGF-1 — approved for severe primary IGF-1 deficiency in children (Laron syndrome etc.). The pharmaceutical counterpart of gray-market IGF-1 LR3.
Identity & type
- Molecular type
- analog
- Origin
- Recombinant human IGF-1 — approved for severe primary IGF-1 deficiency in children (Laron syndrome etc.).
Mechanism of action
IGF-1R activation → growth and anabolism; bypasses GH resistance.
Dosing & routes
Official / clinical context
Approved drug — indications, dosing and warnings are defined by the official label. 0.04–0.12 mg/kg SC twice daily with meals.
Regulator-approved labeling and published study designs — never a recommendation.
Community-reported practice
0.04–0.12 mg/kg SC twice daily with meals. Increlex: in severe IGF-1 deficiency children grow and develop; not used outside the indication due to hypoglycemia risk.
Unverified self-reports. Not medical advice. Not endorsement.
Expected effects (community)
Increlex: in severe IGF-1 deficiency children grow and develop; not used outside the indication due to hypoglycemia risk.
Protocol — official vs community
Official / label
Increlex, for severe primary IGF-1 deficiency (GH receptor/ signaling defects such as Laron syndrome) in children: 0.04–0.12 mg/kg SC twice daily, administered with or shortly after meals.
- 01Start: 0.04 mg/kg twice daily
- 02Increase by 0.04 mg/kg per dose at ≈2-week intervals to maximum 0.12 mg/kg twice daily, guided by IGF-1 levels and growth response
Duration: Chronic through childhood while growth response continues.
Mealtime co-administration and dose escalation are both aimed at the dominant adverse effect, hypoglycemia. Tonsillar hypertrophy and rare intracranial hypertension require monitoring. WADA-prohibited.
Community (anecdotal)
Little direct community use — the gray market prefers IGF-1 LR3, a longer-acting research analogue with no approved product anywhere.
- Cycle:
- —
- Break:
- —
Mecasermin is the pharmaceutical yardstick against which grey-market IGF-1 LR3 dosing folklore is (loosely) calibrated; the LR3 molecule itself has no human safety database.
Human evidence
FDA-approved 2005; also studied in Rett syndrome, ALS.
Preclinical evidence
The preclinical phase was completed and submitted to regulators as part of registration; pharmacology and toxicology details are part of the official label.
Known risks
- Hypoglycemia (more common than LR3), tonsillar hypertrophy, rare intracranial hypertension.characterized
Teal: characterized in clinical/labeling contexts. Amber: theoretical or reported outside controlled settings.
Unknowns & evidence gaps
- Real-world data outside controlled trials