Sermorelin vs Somatropin half-life
Sermorelin has an elimination half-life of about 12 min; Somatropin has about 3.5 h. Somatropin is recombinant human growth hormone itself. Sermorelin is a GHRH analogue that signals the pituitary to release the body's own growth hormone.
Side by side
| Sermorelin | Somatropin | |
|---|---|---|
| Half-life | 12 min (range 10–20 min) | 3.5 h (range 2–5 h) |
| Route | SC | SC daily |
| Category | GH secretagogues | GH & IGF-1 |
| Evidence | Clinical | Clinical |
| Remaining after 24 hours | <0.01% | 0.86% |
| Remaining after 7 days | <0.01% | <0.01% |
| ~97% cleared (5 half-lives) | 1 h | 17.5 h |
| Steady state (4-5 half-lives) | 48 min to 1 h | 14 h to 17.5 h |
Single-dose decay
Share of one dose remaining over time, assuming first-order elimination. Dashed lines mark each half-life.
Sermorelin (t½ 12 min) Somatropin (t½ 3.5 h)
Sermorelin: Former label: about 11–12 minutes. Somatropin: Apparent SC half-life of about 2–5 hours (IV is about 20–30 minutes).
FAQ
Which lasts longer, Sermorelin or Somatropin?
Somatropin lasts longer. Its half-life is about 3.5 h, versus 12 min for Sermorelin, roughly 18 times longer.
How long do Sermorelin and Somatropin stay in your system?
With first-order elimination, about 97% of a single dose is cleared after five half-lives: roughly 1 h for Sermorelin and 17.5 h for Somatropin. Individual clearance varies.
How long until Sermorelin and Somatropin reach steady state?
With consistent repeated dosing, levels approach steady state after 4 to 5 half-lives: about 48 min to 1 h for Sermorelin, and 14 h to 17.5 h for Somatropin.
How reliable are these half-lives?
Sermorelin: Clinical evidence. Somatropin: Clinical evidence. Anecdotal values are community estimates and may be far off.