HGH vs sermorelin

The hormone itself, or the peptide that tells the body to make it — which has evidence, and for what?

No head-to-head trial — cross-trial comparison
In one paragraphGrowth hormone is an approved medicine that works for genuine deficiency and does not work as an anti-ageing drug: in healthy older adults it shifts about 2 kg from fat to lean tissue with no change in weight, while significantly raising rates of swelling, joint pain, carpal tunnel syndrome and gynaecomastia. Sermorelin — the first 29 amino acids of the hormone that releases it — raises growth hormone reliably, which was the basis of its 1990 approval as a diagnostic, but its adult body-composition data are small, open-label studies. Neither has evidence for the anti-ageing use both are sold for. Both are prohibited in sport.

Side by side

A Human growth hormone (somatropin)C Sermorelin
LYO grade (best outcome)A — growth-hormone deficiencyA — growth hormone / IGF-1 rise
LYO grade (body composition, healthy adults)A — effect smallC
LYO grade (anti-ageing)D — tested, and negativeD — not tested
What it isThe hormone: a 191-amino-acid proteinThe releasing signal: GHRH(1-29), 29 amino acids
How it actsReplaces growth hormone directly; works without a pituitaryStimulates the pituitary; needs one that works; pulsatile
ApprovalApproved worldwide for deficiency and other indicationsGeref, 1990–2008, diagnostic and paediatric; brand withdrawn
Evidence in healthy older adultsLiu 2007Meta-analysis, 18 study populations: −2.1 kg fat, +2.1 kg lean, weight unchangedSmall 1990s GHRH(1-29) studies and open-label series; no adequately powered RCT
Documented adverse effectsOedema, joint pain, carpal tunnel, gynaecomastia; a signal for diabetesNo modern controlled long-term dataset
Anti-ageing useDistribution for it is a federal offence in the USCompounded on prescription in the US; unlicensed elsewhere
WADAProhibited (S2)Prohibited (S2)
Verdict

For diagnosed growth-hormone deficiency, growth hormone: it is the treatment, and the question does not arise. For anti-ageing or physique use in healthy adults, growth hormone has evidence and the evidence is negative; sermorelin has almost none. The 'safer because it is natural' argument for sermorelin is a hypothesis about pulsatile release, not a trial result.

Two different things

Growth hormone is the hormone. Sermorelin is the message that asks the pituitary to release it — the active fragment of growth-hormone-releasing hormone. That difference is the whole argument for sermorelin: it can only ever produce what a person's own pituitary can make, in the pulses the body normally uses, whereas injected growth hormone bypasses that control entirely. It is a reasonable physiological hypothesis for why sermorelin might be gentler. It is also the reason its ceiling is lower, and it has never been tested as a claim about outcomes.

What the growth hormone trials found

This is the most important fact in the comparison, because it is the stronger drug being tested for the use both are sold for. A systematic review in Annals of Internal Medicine pooled 18 study populations of growth hormone in healthy older adults. Fat mass fell by about 2.1 kg and lean mass rose by about 2.1 kg — a shift, not a loss, and weight did not change. Alongside it, treated participants were significantly more likely to have soft-tissue oedema, joint pain, carpal tunnel syndrome and gynaecomastia, with a signal for new diabetes and impaired fasting glucose. The authors' conclusion is a single sentence: growth hormone cannot be recommended as an anti-ageing therapy.

Lean mass is body composition, not strength or function. The change is real and it is small, and it came with a side-effect profile that a healthy person is paying for with nothing to treat.

What sermorelin's evidence consists of

Sermorelin reliably raises growth hormone and IGF-1; that response is measured to approval standard in the paediatric diagnostic data behind Geref. A handful of small 1990s studies gave GHRH(1-29) to healthy older adults and confirmed the hormone rises, with modest and inconsistent changes in other measures; the adult 'anti-ageing' use rests on those and on open-label series from compounding-era practice. There is no adequately powered randomised trial of body composition, strength or ageing in healthy adults — so where growth hormone has a negative answer, sermorelin has no answer.

Growth hormone is prescription-only everywhere, and the United States goes further: distributing it for any use other than an approved indication is a federal offence, which is aimed squarely at anti-ageing and physique use. Sermorelin sits in a gap — the brand was withdrawn for commercial reasons, not safety, and pharmacies compound it on prescription in the US; outside the US it is an unlicensed medicine. Both are prohibited in sport at all times.

Questions people actually ask

Is sermorelin safer than HGH?
It has a plausible reason to be — the pituitary stays in control of how much is released. That has never been tested in a trial that compares outcomes, and sermorelin has no modern long-term safety dataset of its own. Plausible is not the same as shown.
Does sermorelin raise growth hormone as much as injecting it?
No. It is bounded by what the pituitary can produce; injected growth hormone is not. That is both the point and the limitation.
Can HGH be prescribed for anti-ageing?
Not lawfully in the United States, where distribution for non-approved uses is a federal offence. The clinical evidence points the same way: the systematic review of trials in healthy older adults concluded against the use.
Which is better for muscle?
Neither has evidence in healthy adults that would justify the use. Growth hormone raised lean mass by about 2 kg in the pooled trials — body composition, not strength — at the cost of significant side effects. Sermorelin's adult data are too small to say.

References

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    Liu H, Bravata DM, Olkin I, et al. Systematic review: the safety and efficacy of growth hormone in the healthy elderly.Ann Intern Med, 2007;146:104–11518 study populations; the definitive assessment of anti-ageing use.
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