Recombinant hormone

Somatropin is recombinant human growth hormone — the 191-amino-acid protein itself, which is what "HGH 191AA" on a vial means. It is a long-approved prescription medicine for growth hormone deficiency and several causes of short stature. Outside those uses, the evidence is much less flattering than its reputation. In healthy older adults, a meta-analysis of 18 study populations found about 2.1 kg more lean mass and 2.1 kg less fat, no weight change, no improvement in bone density, and significantly more soft-tissue swelling, joint pain, carpal tunnel syndrome, gynaecomastia and new diabetes — concluding it cannot be recommended as an anti-ageing therapy. In young athletes the pattern repeats: lean mass up 2.1 kg, strength and exercise capacity not improved, and more swelling and fatigue.