HGH / Somatropin Guide

Recombinant human growth hormone (somatropin) is the gold standard for treating diagnosed GH deficiency and is widely prescribed off-label at longevity clinics. This guide covers everything from mechanism and FDA-approved brands to dosage protocols, IGF-1 monitoring, and when peptide therapy is a better choice. Track your HGH protocol, IGF-1 labs, and body composition changes with Shotlee — the free injection tracking app.

Somatropin is recombinant human growth hormone (rHGH) — a 191 amino acid protein identical in sequence and structure to endogenous pituitary GH. It is produced via recombinant DNA technology in yeast or mammalian cell cultures, resulting in a biologically identical molecule to what the pituitary gland secretes naturally.

The FDA has approved somatropin for multiple indications: adult and pediatric growth hormone deficiency, Turner syndrome, HIV-associated wasting (as Serostim), short bowel syndrome, and Prader-Willi syndrome. Off-label use for anti-aging, longevity, and body composition is widespread at private longevity clinics — it is legal for physicians to prescribe off-label, though it is not legal to market for performance enhancement.

Mechanism: Somatropin exerts both direct effects (lipolysis, reduced glucose uptake, protein synthesis stimulation) and indirect effects via IGF-1 produced by the liver in response to GH signaling. IGF-1 then acts on GH receptors throughout the body to drive anabolic, anti-catabolic, and mitogenic effects.