What does Mecasermin do? Benefits and evidence

Mecasermin copies human IGF-1 and is approved as Increlex for specific rare causes of childhood growth failure. Adult muscle-building and longevity benefits are unproven. Growth studies and safety registries support its childhood use. It can cause severe low blood sugar and unwanted tissue growth.

• Increlex is approved for children age 2 and up whose poor growth comes from severe primary IGF-1 deficiency. (Drug label)
• In a registry of treated patients, final height improved, especially when treatment began before puberty. (Studied in a trial)
• In a small controlled study, it helped growth in people whose bodies cannot respond to growth hormone. (Studied in a trial)

Uses in the sources

• FDA-approved from age 2 for growth failure due to severe primary IGF-1 deficiency, or GH gene deletion with neutralizing GH antibodies. (Drug label) (source)
• Studied for ALS, Rett syndrome, Phelan-McDermid syndrome, diabetes and other conditions. These are not FDA-approved indications. (Studied in a trial) (source)
• Bodybuilding forums discuss Increlex, often confusing it with LR3 or an IGF-1/IGFBP-3 complex. Benefits and product identity are uncertain. (Reported by users) (source)