Sermorelin
Also known as: GRF 1-29, Sermorelin acetate, Geref
The shortest-acting GHRH analogue — the most physiological way to raise growth hormone, and the reason it has largely been replaced by CJC-1295, which does the same thing for longer.
Substance family
Growth hormone itself and the peptides that prompt the body to release it. Effects build over months rather than weeks, and reduced insulin sensitivity is what limits duration.
Effects on
Which outcomes this substance acts on — descriptive, not a recommendation.
Strain profile
Where this substance is most likely to hit — a rough orientation, individually dependent on dose, duration and predisposition.
This substance causes
Dosing & protocols by goal
Rough orientation ranges as reported in harm-reduction literature — not an individual treatment plan. Doses are individual and open-ended; frequency depends on the ester or half-life.
Raising growth hormone
AncillaryDose
100–300 mcg
Frequency
1× / day at bedtime, fasted
Cycle length
Cyclical, months
Bedtime because it works with the body's own largest nightly pulse rather than against the daily rhythm.
Combined with a secretagogue
AncillaryDose
100–300 mcg with GHRP-2 or ipamorelin
Frequency
1–2× / day
Cycle length
Cyclical
The two mechanisms are synergistic: the GHRH analogue raises how much is released, the secretagogue triggers the release.
Side effect & countermeasure
Typical problems and what you can do to reduce harm — at a glance. Does not replace medical monitoring.
Problem
Very little seems to happen
Countermeasure
The half-lifehalf-lifeHow long it takes for half the substance to leave the body — it determines dosing frequency, not duration of effect. is under twenty minutes, so timing matters more than with anything else in this class. Fasted, and not after a meal containing fat or carbohydrate — otherwise the pulse is blunted before it starts.
Problem
Blood glucose creeping up
Countermeasure
Milder here than with sustained GH, because the pulse pattern is preserved, but still present. Fasting glucose and HbA1c periodically.
Overview
Sermorelin is the first 29 amino acids of natural growth hormone-releasing hormone — the active fragment, and effectively the body's own signal.
That makes it the most physiological option in this class: it raises growth hormone by asking the pituitary to release its own, in its own pattern, subject to the body's own feedback. It cannot produce the sustained, unregulated levels that injected growth hormone can.
It is also almost obsolete, for one practical reason.
Mechanism of Action
GHRH tells the pituitary to release growth hormone. Sermorelin is that signal, shortened to its working part.
Because the pituitary's own regulation stays in place — somatostatin still applies the brake, feedback still operates — the result is a bigger version of a normal pulse rather than a flat elevated level. That is the argument for this whole class over exogenous GH.
Why CJC-1295 replaced it
Ten to twenty minutes. That is the half-life, and it is the entire story.
CJC-1295 is a modified GHRH analogue built specifically to last longer, which means fewer injections for a comparable effect. Sermorelin needs precise timing and frequent administration to achieve what CJC-1295 does more conveniently.
Sermorelin survives mainly in prescribing contexts — compounding pharmacies and anti-aging clinics in the US — where its longer regulatory history matters more than its inconvenience.
Timing is not optional here
With a twenty-minute half-life, everything depends on the conditions at the moment of injection.
Food blunts the GH response, particularly fat and carbohydrate. Injected after a meal, most of the effect simply does not happen. Fasted at bedtime, it overlaps with the body's own largest nightly pulse — which is why that is the standard timing rather than a preference.
Side Effects & Risks
- Rising blood glucose over time, though milder than with sustained GH
- Water retention at higher doses
- Injection site redness — more common with sermorelin than with several others
- Flushing, headache, tiredness after injection
- Vivid dreams or disrupted sleep in some people
Blood Work & Monitoring
- IGF-1 — the practical measure of whether it is doing anything
- Fasting glucose and HbA1c — periodically
- Thyroid panel during longer use
Harm-Reduction Notes
- Fasted, at bedtime, or you are largely wasting it
- Combined with a secretagogue rather than alone — the two mechanisms multiply
- If injection frequency is the obstacle, CJC-1295 is the same idea built to last longer
- Cycle it, and watch glucose over months rather than weeks
- Prohibited in tested sport at all times
Legal status by region
Regulation differs considerably between jurisdictions and changes over time. This is a rough orientation, not legal advice — check the rules that apply where you are.
| Region | Regulatory status |
|---|---|
| United States | Available through compounding pharmaciesWidely prescribed in anti-aging clinics; the original product was withdrawn. |
| EU / UK | Not approved as a medicine |
| Canada / Australia | Restricted |
| Parts of Asia, Latin America & Middle East | Availability varies |
| Competitive sport | ProhibitedGHRH analogues are prohibited at all times. |