How long does Sermorelin stay in your system?
Sermorelin has a published half-life of 4.3 ± 1.4 minutes. By the standard pharmacology rule of thumb, a drug is about 97% eliminated after roughly five half-lives, which here works out to about 21.5 minutes. That is a disappearance half-time during constant intravenous infusion, not a classic post-dose elimination half-life.
Source: Soule et al., J Clin Endocrinol Metab 1994 (PMID 7962295) · Peer-reviewed · measured: intravenous infusion · dataset reviewed September 23, 2026
What is the half-life of Sermorelin?
Sermorelin's published value is 4.3 ± 1.4 minutes, from a 1994 study in the Journal of Clinical Endocrinology and Metabolism. Sermorelin is GHRH(1-29), the shortest fragment of growth hormone-releasing hormone that keeps full activity, and it prompts the pituitary to release the body's own growth hormone rather than supplying any.
The measurement deserves precision. It was a disappearance half-time measured during constant intravenous infusion in 10 normal men, not a classic elimination half-life after a single dose. The two are related but not identical, so the figure tells you sermorelin clears within minutes without being an exact post-dose value.
How much Sermorelin is left after each half-life?
Each half-life removes half of whatever is left, so the percentages are pure arithmetic and the same for any compound; only the clock changes. For Sermorelin, one half-life is 4.3 minutes. The rows below run that forward for a single amount with nothing added.
| Half-lives elapsed | Time elapsed | Remaining | Cleared |
|---|---|---|---|
| 1 | 4.3 minutes | 50% | 50% |
| 2 | 8.6 minutes | 25% | 75% |
| 3 | 12.9 minutes | 12.5% | 87.5% |
| 4 | 17.2 minutes | 6.25% | 93.75% |
| 5 | 21.5 minutes | 3.13% | 96.88% |
| 6 | 25.8 minutes | 1.56% | 98.44% |
| 7 | 30.1 minutes | 0.78% | 99.22% |
Why do the numbers differ between sources?
The figure most often repeated for sermorelin is 11 to 12 minutes, attributed to the Geref label. We could not verify it. Geref was withdrawn and its label is not retrievable on DailyMed or accessdata, so there is no way to check what it said.
That leaves the 1994 infusion study as the best traceable source. The 11 to 12 minute figure may well have appeared on the label, but an unverifiable number is not one we will present as established.
What does a half-life not tell you?
Sermorelin leaves plasma within minutes, but the growth hormone pulse it provokes lasts longer, and the IGF-1 made in response longer still. Its effect also depends on an intact pituitary and stays subject to normal brakes such as somatostatin and IGF-1 feedback. None of that is captured by the half-life.
Nor does it support the claim that a more physiological growth hormone profile translates into better outcomes. That pharmacodynamic argument has not been shown to produce superior clinical results compared with recombinant growth hormone.
Can you run the numbers yourself?
The estimator applies the same decay arithmetic to any half-life, starting amount and time you enter. It opens with Sermorelin's published value loaded. Type another figure to see how sensitive the result is to it.
Published value: 4.3 ± 1.4 minutes (Intravenous infusion) · Soule et al., J Clin Endocrinol Metab 1994 (PMID 7962295) · Compound profile
Show the math
What are the limits of this estimate?
Everything above is a single-compartment approximation: one pool of drug, falling by the same fraction in every interval. Real elimination varies with kidney and liver function, body composition, formulation and route, and a published figure describes only the route and the people it was measured in. Many compounds also show a fast distribution phase before the slower elimination the table describes.
A half-life is not a dosing schedule. Labelled intervals come from clinical trials that measured outcomes and tolerability, and nothing on this page suggests when to take, repeat or stop anything. Whether Sermorelin is out of your system for drug-testing purposes is a different question again. Tests often look for metabolites rather than the parent compound, and the answer depends on the assay, its sensitivity and the sample type, none of which a plasma half-life captures.
FAQ.
Is sermorelin's half-life 4 minutes or 12 minutes?
The traceable figure is 4.3 ± 1.4 minutes, a disappearance half-time measured during constant intravenous infusion in 10 normal men. The 11 to 12 minute figure attributed to the Geref label could not be verified, because the withdrawn label is no longer retrievable.
Does the sermorelin half-life apply to compounded sermorelin?
Not directly. Compounded products have no label pharmacokinetics of their own, and route and formulation change how a peptide is absorbed, so an intravenous infusion figure cannot be assumed to describe them.
How is sermorelin different from CJC-1295?
Sermorelin is unmodified GHRH(1-29) and clears in minutes. CJC-1295 with DAC is a modified analogue whose drug affinity complex binds albumin, giving a half-life of 5.8 to 8.1 days. CJC-1295 without DAC has no published human half-life.
For what the evidence on Sermorelin actually shows, read the Sermorelin profile. For approval and regulatory position, see is Sermorelin legal. The half-life reference lists every sourced value side by side, including the compounds where a number circulates online with no reliable human data behind it.