Category
Growth hormone secretagogues, GHRH analogues and the growth factors downstream of them. Evidence quality varies more inside this group than in any other on the site.
Most of this category is about growth hormone, approached sideways. Instead of administering GH, these compounds ask the pituitary to release its own. That keeps the pulsatile rhythm the body normally uses, and it puts a ceiling on the result: you cannot release more than the gland has.
Two questions get asked as one here, and they have very different answers. Does the compound raise GH and IGF-1? For several of these, yes, and it has been measured. Does that turn into the muscle, strength or recovery people are actually after? Much thinner ground, and the profiles say so.
A selective growth hormone secretagogue that prompts a short pulse of GH release. Widely used, and supported almost entirely by early pharmacology rather than outcome trials.
Muscle & performance · Anti-aging & longevity
A GHRH analogue that raises growth hormone by amplifying the body's own release signal. Sold in two forms whose durations differ by two orders of magnitude.
Muscle & performance · Anti-aging & longevity
A GHRH analogue approved by the FDA for reducing excess visceral fat in HIV-associated lipodystrophy. The only compound in this category with completed phase 3 trials.
Muscle & performance · Weight loss · Anti-aging & longevity
An orally active ghrelin receptor agonist that raises growth hormone and IGF-1. Not a peptide, and not injected. It is a small molecule taken by mouth.
Muscle & performance · Anti-aging & longevity
A growth hormone releasing peptide approved in Japan as a diagnostic agent. It triggers a pulse of your own growth hormone rather than supplying any.
Muscle & performance · Anti-aging & longevity
The oldest of the growth hormone releasing peptides, and the one with the strongest effect on hunger. That appetite stimulation is the defining fact about it.
Muscle & performance · Anti-aging & longevity
The most potent growth hormone releasing peptide of the three, and the only one that reliably stops working. Its response fades within about two weeks of continuous use.
Muscle & performance · Anti-aging & longevity
A modified insulin-like growth factor engineered to last far longer in the body than the natural hormone. It can cause hypoglycaemia, which makes it the most acutely dangerous compound on this site.
Muscle & performance
A 16-amino-acid peptide encoded by mitochondrial rather than nuclear DNA, studied in animals for effects on metabolism and exercise capacity.
Anti-aging & longevity · Muscle & performance
A splice variant of IGF-1 released by damaged muscle, pegylated to last longer. No human trials, and the same proliferation concern as everything in the IGF family.
Muscle & performance
A melanocortin receptor agonist approved by the FDA for low sexual desire in premenopausal women. It acts on the brain rather than on blood flow.
Muscle & performance
A myostatin-blocking protein with dramatic animal results, no human trials, and a serious question over whether what is sold is the real thing.
Muscle & performance
The master switch above the reproductive hormone axis. Unusually for this category, it has a serious academic research programme in humans behind it.
Muscle & performance
Natural GnRH, approved as a diagnostic agent. Widely used alongside testosterone therapy on a rationale that is sound in principle and unstudied in that setting.
Muscle & performance
An approved medicine for people with a growth hormone deficiency. Used without that diagnosis it is a controlled substance in the United States, and the anti-ageing claims it is sold on were retracted by their own author.
Muscle & performance · Anti-aging & longevity
An approved fertility medicine that mimics LH. Widely used to keep the testes working during testosterone therapy. Also sold, separately, for a weight-loss diet the FDA has said outright does not work.
Muscle & performance
Not a peptide, and the most consequential thing on this site. Approved replacement therapy for diagnosed hypogonadism — a Schedule III controlled substance — and something that will make you infertile while you take it.
Muscle & performance
An essential cofactor for burning fat, and not the step that limits it. Approved for genuine carnitine deficiency; sold by injection for weight loss on weak evidence.
Weight loss · Muscle & performance
A mouse compound that got a press release. It reproduced some effects of endurance training in mice, and no human has ever taken it.
Weight loss · Muscle & performance
Three growth hormone secretagogues in one vial, commonly 6:3:3. Two of the three do the same job, which is the thing worth knowing before buying it.
Muscle & performance · Anti-aging & longevity
The original GHRH analogue, and the only one here that once held FDA approval, withdrawn for commercial reasons and not for safety.
Muscle & performance · Anti-aging & longevity
GHRH analogues imitate the hypothalamic signal that tells the pituitary to release GH. Sermorelin, CJC-1295 and tesamorelin are the ones people encounter. Ghrelin mimetics — also called secretagogues — come at the same pituitary through a different receptor — ipamorelin, GHRP-2, GHRP-6, hexarelin, and MK-677, which is orally active and not a peptide at all.
Combining one of each releases more GH than either does alone. That is the whole reason CJC-1295 with ipamorelin has dominated this category for a decade, and it is why our stack pages treat the pair as one plan rather than two protocols that happen to overlap.
Within each family the difference is selectivity. Ipamorelin is the one usually picked for releasing GH without much effect on cortisol or prolactin. The older GHRPs are messier. IGF-1 LR3 and PEG-MGF skip the pituitary entirely and supply the growth factor directly. Follistatin-344 belongs to none of this: it targets myostatin, and the human evidence is close to nonexistent.
Tesamorelin is the useful yardstick. It has an approved indication, visceral fat in HIV-associated lipodystrophy, and trial data behind it. That is one population and one endpoint. It is still more than anything else in this group can claim.
For the rest, the measured outcome is usually a number in blood. A compound that reliably raises IGF-1 has demonstrated that it raises IGF-1. Lean mass, strength and recovery time are separate claims that need separate evidence, and each profile states which of the two its citations actually support.
This is the category where testing matters. WADA's prohibited list carries a catch-all for any substance without regulatory approval for human therapeutic use, and that clause covers most of what is on this page whether or not the specific name appears anywhere else on the list.
Check against the clause, not the index.
Last updated 21 Aug 2026