Sermorelin
GRF 1-29
Bioidentical GHRH fragment used diagnostically and off-label to stimulate endogenous growth hormone.
Key takeaways
- Bioidentical GHRH(1-29) — stimulates your own pulsatile GH release rather than replacing it.
- Very short half-life (~10–20 min) drives once- or twice-daily subcutaneous dosing, usually before bed to match the nocturnal GH pulse.
- Was FDA-approved as a diagnostic for GH deficiency (discontinued for commercial, not safety, reasons); the anti-aging evidence is much thinner.
- Off-label protocols typically run 8–12 weeks before assessing response via IGF-1.
Overview
What it is
Sermorelin is a synthetic bioidentical fragment of growth hormone-releasing hormone, the active GHRH(1-29) sequence, which is the minimal length needed to stimulate the GHRH receptor on the pituitary. It triggers pulsatile endogenous growth hormone release rather than introducing exogenous GH, which is the conceptual appeal for anti-aging and recovery use.
Pharmacokinetics
Its half-life is very short, roughly 10 to 20 minutes, with around 50% bioavailability. That drives once- or twice-daily subcutaneous dosing in research and off-label contexts, usually before bed to amplify the natural nocturnal GH pulse.
What the evidence says
Sermorelin was FDA-approved as a diagnostic agent for growth hormone deficiency and discontinued for commercial, not safety, reasons, so its short-term safety in humans is reasonably characterized. The evidence base for the anti-aging and recovery uses that drive current interest is much thinner than the diagnostic literature.
Reported dosing protocols
Protocols reported in research literature and clinic/community use — informational context, not a dosing recommendation.
| Use case | Dose | Route | Frequency | Duration |
|---|---|---|---|---|
| GH support (off-label) | 100–300 mcg | SubQ | Once daily before bed | 8–12 weeks |
Pharmacokinetic summary
- Model tier
- Simple (t½ + F, Tmax estimated)
- Half-life
- 14 min
- Bioavailability
- 50%
- Typical dose
- 0.15–0.5 mg
Frequently asked questions
Is sermorelin the same as HGH?
No. Sermorelin is a GHRH fragment that stimulates the pituitary to release your own growth hormone in pulses. Exogenous HGH replaces the hormone outright and flattens the pulsatile pattern. Sermorelin's effect is self-limiting through normal feedback loops.
Why is sermorelin injected at night?
Endogenous GH release peaks during early sleep, and GHRH analogs amplify that natural pulse. Bedtime dosing lines the exogenous stimulus up with the body's own rhythm and is the standard pattern in clinic protocols.
How long until sermorelin shows effects?
GH-axis changes are gradual. Clinics typically run 8–12 weeks before judging response, tracked with IGF-1 levels rather than subjective feel. Sleep quality changes are usually the first thing reported.
References
- Estimated — Native GHRH(1-29); very short half-life (~10–20 min).
Related compounds
CJC-1295 with DAC
Long-acting GHRH analog with a drug-affinity complex that extends half-life to ~6–8 days; weekly dosing.
CJC-1295 without DAC (Modified GRF 1-29)
Short-acting GHRH analog (~30 min half-life) usually paired with a GHRP for pulsatile GH release.
Tesamorelin
N-terminally stabilized GHRH analog approved to reduce excess visceral fat in HIV lipodystrophy.
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