Growth Hormone Axis research peptides, read as the literature actually wrote them

The short version

steroidnpeptides is a reading desk for three peptides that act on the growth hormone axis — the signalling chain that runs from the brain to the pituitary gland to the liver and sets how much growth hormone the body releases. The three are ipamorelin, CJC-1295 and tesamorelin.

None of them is a hormone replacement. Each one prompts the pituitary to release the body's own growth hormone, which is a different thing from injecting growth hormone directly.

Two of the three have no approved medical use anywhere and are handled as research chemicals; ipamorelin's only published Phase 2 trial did not meet its primary endpoint ^[3]. The third, tesamorelin, is an approved prescription drug in the United States, but only for one narrow condition — excess abdominal fat in adults with HIV-associated lipodystrophy ^[14].

This desk reports what the published studies measured and stops there. It recommends no dose, sells nothing, and is not a clinic. Where the research is thin, it says so in the sentence rather than in a footnote.

What this desk covers, and what it does not

The domain name pairs two categories that people tend to search for together. This desk covers only one of them.

Anabolic-androgenic steroids are a controlled-substance class in the United States and in most other jurisdictions. Nothing on this site describes how to obtain them, how they are used, how they might be combined with anything else, or how any legal restriction on them might be worked around. There are no protocols here, and none is coming.

The compounds this desk does cover — ipamorelin, CJC-1295 and tesamorelin — are not presented as substitutes for that class, as gentler versions of it, or as anything that belongs alongside it. They act through different receptors, on a different organ, and their published evidence base was assembled to answer entirely different questions. Treating the two categories as interchangeable is the single most common error in how these molecules get discussed, and correcting it is most of what this site is for.

All three compounds are prohibited in sport at all times under category S2 of the World Anti-Doping Agency's list — peptide hormones, growth factors, related substances and mimetics — and the class is detectable by accredited anti-doping laboratories. CJC-1295 has in fact been identified by high-resolution mass spectrometry as the active ingredient of an unlabelled preparation seized in an anti-doping context ^[7]. That is a statement of fact about the compounds, not advice about competition.

Two literatures that barely touch

There is a body of writing about these three peptides that lives on message boards, and there is a body of writing that lives in journals. They share the compound names and very little else.

The forum literature is organised around appearance and training: recovery, leanness, sleep, how one compound is said to feel next to another. The published literature is organised around endpoints a study can measure and a regulator can read.

Ipamorelin's only controlled human trial asked whether it shortened the time to a first tolerated meal after bowel resection. It did not: median 25.3 hours against 32.6 hours on placebo, with the difference well short of significance ^[3]. Its most recent published in-vivo work is a ferret study of chemotherapy-associated weight loss ^[1]. Before that, a rat study measured longitudinal bone growth in micrometres per day ^[5].

CJC-1295's human record is a small set of early pharmacology studies asking how long the compound persists, how far growth hormone and IGF-1 rise, and whether the natural pulsatile rhythm survives continuous stimulation ^[9][10].

Tesamorelin's record is the largest of the three and the most conventional, built on square centimetres of visceral adipose tissue in adults with HIV-associated lipodystrophy ^[13][15][17].

Not one of those studies measured a physique. The distance between the two literatures is not a gap to be argued across — it is the finding, and it is the reason this desk exists.

What a research peptide is

A peptide is a short chain of amino acids, shorter than a protein. In this class the chains run from five residues to forty-four: ipamorelin is a pentapeptide, tesamorelin a forty-four-residue analogue of human growth-hormone-releasing hormone. Length is not trivia — it determines how the molecule is manufactured, how quickly enzymes in the blood take it apart, and whether it survives long enough to reach a receptor at all. Much of the chemistry in this field is spent on that last problem, whether by substituting protease-resistant residues or by attaching the peptide to a carrier already circulating in the blood ^[12].

Research chemical is a supply category, not a pharmacological one. It means the material is sold for laboratory use and is not manufactured, tested or released under the quality systems that govern approved medicines. Purity, identity and sterility go unverified in that channel, and the literature records this as a documented gap rather than a hypothetical one.

Tesamorelin is the exception on this desk. As an approved prescription product it is made to pharmaceutical standards for its licensed indication ^[14]; research-grade material sold under the same name is not the same article and carries none of the same assurances.

Every claim on this site carries a bracketed number that resolves to an entry on the references page. Where a finding comes from a rat, a mouse or a ferret, the sentence says so, because the species is part of the finding rather than a caveat attached to it.