HGH vs Sermorelin
Inject the hormone itself, or ask your pituitary to make more? The trade-offs are not subtle.
Reviewed by the amino101 editorial team. , first published .
HGH and sermorelin are the two ends of the growth hormone decision. HGH, recombinant somatropin, is the 191 amino acid hormone itself: inject it and GH levels rise regardless of what your pituitary is doing, and your own production shuts down through feedback while you use it. Sermorelin is the first 29 amino acids of GHRH, the signal that tells the pituitary to release GH, so it only works through a functioning pituitary and the body's feedback loop stays intact. HGH is an approved drug for growth hormone deficiency with strong evidence in true deficiency and a more modest, side effect heavy record in healthy adults, where meta-analyses found a few kilograms of body composition change and no strength gain. Sermorelin was approved as Geref until 2008 and has older trials showing modest IGF-1 and lean mass gains in adults over 55. HGH is a controlled prescription drug in most countries; sermorelin is compounded on prescription. Both are prohibited by WADA. Educational comparison only.
| HGH (Somatropin) | Sermorelin | |
|---|---|---|
| Typical dosage | 1 to 4 IU per day | 200 to 500 mcg |
| Frequency | once daily, or split into two doses | once daily |
| Route | Subcutaneous, Intramuscular | Subcutaneous |
| Half-life | 2 to 3 hours in plasma after subcutaneous injection; IGF-1 stays elevated for about 24 hours | 10 to 20 minutes in plasma |
| Cycle | 3 to 6 months minimum for body composition; medical replacement is ongoing | 3 to 6 months |
| Research level | Extensively studied | Extensively studied |
| Human trials | Approved drug | Approved drug |
| Status | FDA approved for growth hormone deficiency and several other indications; off-label and unlicensed use is widespread | Formerly FDA approved (Geref, withdrawn 2008); widely available via compounding pharmacies |
| Effects timeline | water retention and deeper sleep 1 to 2 weeks, skin and recovery 3 to 4 weeks, fat loss 8 to 12 weeks, lean mass 3 to 6 months | sleep quality 1 to 2 weeks, IGF-1 rise on bloodwork 4 to 6 weeks, body composition and skin 2 to 3 months if at all |
Key differences
HGH (Somatropin) vs Sermorelin dosage
Dosage patterns reported in research and community protocols, by goal. Taken from each compound page. Not a prescription.
| Goal | Dosage | Frequency |
|---|---|---|
| Anti-aging, recovery, skin | 1 to 2 IU | once daily on waking or before bed |
| Body composition | 3 to 4 IU | split into two doses, morning and evening or post-training |
| Injury recovery support | 2 IU | once daily before bed |
| Medical adult replacement | roughly 0.6 to 1.5 IU (0.2 to 0.5 mg) | once daily, titrated to IGF-1 |
| Goal | Dosage | Frequency |
|---|---|---|
| Clinic standard | 200 to 300 mcg | once daily before bed |
| Higher single dose | 500 mcg | once daily before bed |
| Stacked with a GHRP | 200 mcg | once daily before bed, with 100 mcg ipamorelin |
| 5 on 2 off variant | 300 mcg | once daily, weekdays only |
Convert any of these to syringe units in the dosage calculator.
Side effects compared
- ▲Fluid retention, swollen hands and feet
- ▲Joint pain and stiffness
- ▲Carpal tunnel symptoms, tingling and numb fingers
- ▲Elevated blood glucose and reduced insulin sensitivity
- ▲Headache
- ▲Injection site redness, itching, or small lumps
- ▲Flushing or warmth shortly after a dose
- ▲Headache or dizziness
- ▲Mild water retention
- ▲Drowsiness, which is why bedtime dosing is preferred
Which should you choose?
HGH is the fit for diagnosed growth hormone deficiency under medical supervision, and for experienced users who want a larger, dose dependent effect on fat and recovery and will monitor IGF-1 and fasting glucose. It is the only option when the pituitary cannot respond to a secretagogue. Reported ranges are 1 to 2 IU daily for recovery and 3 to 6 IU for body composition. Buy only from a pharmacy; the grey market is heavily counterfeited.
Sermorelin is the fit for someone who wants a modest, physiological lift in GH without shutting down their own production, who prefers a compound that preserves feedback, or who is working through a clinic. 200 to 300 mcg at bedtime on an empty stomach is the common dose. Expect a smaller effect than HGH and plan to add ipamorelin if the response is underwhelming.
HGH does more and costs more in every sense. The effect on fat and water is larger, the IGF-1 rise is bigger, and so are the side effects: fluid retention, joint pain, carpal tunnel symptoms and raised blood glucose are common above 2 IU daily, and your own pituitary output is suppressed while you use it. Sermorelin does less, with a ceiling set by what your pituitary can release, but it keeps the natural pulsatile pattern and the feedback loop, which is why clinics prefer it for people over 40 who want a modest lift rather than replacement. The choice is clear at the extremes. Diagnosed growth hormone deficiency is a medical condition treated with HGH under monitoring. Mild age related decline with a goal of better sleep, skin and recovery is where sermorelin, ideally paired with ipamorelin, fits. The grey area in between is where people get hurt, usually by running HGH at body composition doses without bloodwork. The peptide dosage chart has the reported ranges for both.
Stacking: Not stacked together; exogenous HGH suppresses the pituitary that sermorelin is trying to stimulate. HGH is paired with IGF-1 LR3 or healing peptides; sermorelin is paired with ipamorelin.
HGH is recombinant human growth hormone, a 191 amino acid protein identical to what the pituitary makes. It is an approved drug for growth hormone deficiency and is used off-label for fat loss, muscle preservation, recovery, and anti-aging.
Sermorelin is the first 29 amino acids of natural growth hormone releasing hormone, the shortest fragment that still fully activates the receptor. It was once an approved diagnostic and pediatric drug and is now the most common growth hormone secretagogue prescribed by anti-aging and wellness clinics.
HGH vs Sermorelin: frequently asked
Is sermorelin as good as HGH?
No, and it is not meant to be. Sermorelin can only release what your pituitary can make, so its effect is capped; HGH adds hormone directly and the effect scales with dose. Sermorelin's advantage is safety: it preserves pulsatility and feedback, so IGF-1 rarely overshoots and side effects are milder.
Does sermorelin shut down natural growth hormone production?
No. It stimulates the pituitary through the normal pathway, and the body's feedback remains intact. HGH does suppress natural production while in use, which is why some people step it down over a week or two when stopping.
Can you take HGH and sermorelin together?
There is little point. Exogenous HGH suppresses the pituitary through feedback, which blunts the response to sermorelin. People who want both direct and stimulated GH usually alternate rather than combine, and even that has no trial support.
How much HGH equals sermorelin?
There is no conversion. Sermorelin at 200 to 500 mcg produces one short pulse whose size depends on your pituitary; HGH at 1 to 4 IU delivers a fixed amount regardless. Bloodwork, specifically IGF-1, is the only way to compare what each is doing in a given person.
Is HGH or sermorelin legal?
HGH is an approved prescription drug, and in the US distributing it for off label uses like anti-aging or bodybuilding is restricted by federal law. Sermorelin was approved until 2008 and is now compounded on prescription. Both are prohibited by WADA.
Which is better for anti-aging, HGH or sermorelin?
Sermorelin is what clinics use, because the modest physiological rise fits the goal and the side effect profile is mild. HGH in healthy older adults produced small body composition changes with no strength or function gain and a meaningful rate of edema, joint pain and carpal tunnel in meta-analyses. For most people the risk of HGH outweighs the benefit in that setting.
Related reading
Muscle growth and body composition
One is a GHRP, one is a GHRH analog. Why are they compared, and why are they usually combined?
Two GHRH analogs with approval histories. Which one still earns the price?
The messenger and the hormone. Why one is a cell culture reagent and the other is an approved drug.
GLP-1
Guide
Sources
- Effects of human growth hormone in men over 60 years old. New England Journal of Medicine, 1990
- Systematic review: the safety and efficacy of growth hormone in the healthy elderly. Annals of Internal Medicine, 2007
- Effects of nightly GHRH 1-29 administration in healthy older men and women. Journal of Clinical Endocrinology and Metabolism, 1997