The GH axis outside the peptide vial
The recombinant hormone has 54,472 articles, 183 phase 3 trials, and 9 active registrations; the secretagogues the community uses instead have zero active registrations
Experimental material. Read before using anything from here.
Nothing on this page is a medical recommendation, prescription or treatment plan. It is an organized translation of protocols circulating in research communities and, where it exists, of what published trials tested. The two are marked differently — and they are not equivalent.
Most of the compounds here have no FDA approval for human use. Several are sold labeled "research use only", which means they have not gone through purity, sterility or dosage controls for human consumption. A community-reported dose is not a validated dose: it is what someone reported having done.
Talk to a licensed health professional before considering any of these compounds. If you already use one and feel anything unexpected, seek care — do not wait for the next routine test.
Summary
This site already covers seven compounds from the growth hormone axis: CJC-1295 with and without DAC, GHRP-6, ipamorelin, sermorelin, tesamorelin, and IGF-1 LR3. Missing were the ones that come up in the same conversation and aren't a research injectable peptide — the oral secretagogue MK-677, GHRP-6's cousins (GHRP-2 and hexarelin), the whole recombinant hormone, and the two IGF formulations that have a pharmaceutical name. The contrast is what the page is about. Somatropin — recombinant GH, the product with a package insert — has 54,472 articles on PubMed, 817 registered studies, 183 of them phase 3, and 9 active registrations. GHRP-2 and hexarelin, which the community discusses as if they were alternatives, have zero registered studies on ClinicalTrials.gov. That's not scant evidence: it's none, where trials get registered.
Why split the GH axis into two shelves
The entire growth-hormone axis can be worked from three angles: giving the ready-made hormone (somatropin), asking the body to release its own (the secretagogues — CJC, ipamorelin, GHRP, MK-677), or skipping the hormone and giving the downstream mediator (IGF-1). This site already had the injectable secretagogues and IGF-1 LR3. What was missing were the three pharmaceutical-named ends.
The question this page answers is not which one works best — it's where the evidence is. And it's concentrated on one side only.
Two rows need a methodological caveat, and it's written before the number, not after. somatropin on PubMed falls under the class descriptor and returns the entire growth-hormone literature, which makes the number a ceiling, not a measure of the product. And "mechano growth factor" in the intervention field on ClinicalTrials.gov returns registrations that mention the expression without being about MGF — the largest of them also shows up in the search for mecasermin. I publish both numbers with the caveat because removing them would be choosing the result.
No number on this page came from the site's secondary source.
How much evidence exists, compound by compound
The numbers below were compiled by me on September 12, 2026, on PubMed and ClinicalTrials.gov. Each row's query is written out in full, next to the number, so anyone can repeat it and contradict me — and so the script that rechecks this site's counts can run all of them.
The condition column is not a claim about mechanism: it's the Condition field copied from the phase 3 records that the search itself returned. When there is no phase 3 record, the cell says so.
| Compound | Condition in phase 3 registrations | Query | Articles in PubMed | Studies on ClinicalTrials.gov |
|---|---|---|---|---|
| MK-677 | Growth Hormone Deficiency (GHD) | ibutamoren OR "MK-677" OR "MK-0677" | 161 | 8 |
| GHRP-2 | no phase 3 registration in this search | "GHRP-2" OR pralmorelin | 256 | 0 |
| Hexarelin | no phase 3 registration in this search | hexarelin | 313 | 0 |
| Somatropin | SGA; Turner Syndrome; Noonan Syndrome; ISS | somatropin | 54.472 | 817 |
| MGF | Crohn Disease; Growth Hormone Insensitivity Syndrome (GHIS); Laron Syndrome; Insulin-Like Growth Factor-1 Deficiency | "mechano growth factor" | 205 | 105 |
| Mecasermin | Crohn Disease; Insulin-Like Growth Factor-1 Deficiency; Growth Disorders | mecasermin | 103 | 37 |
| PEG-IGF-1 | no phase 3 registration in this search | "PEG-IGF-1" | 6 | 0 |
What exists in phase 3, and who it belongs to
Article count measures academic attention, not outcome evidence. The table below separates what has a registered phase 3 trial — and shows the largest registration the search returned in each row, with the declared number of participants and the sponsor.
A registration is not a result. A recruiting phase 3 trial is declared intent with money behind it, and nothing more than that.
| Compound | Query | Registered phase 3 trials | The largest registration I opened |
|---|---|---|---|
| MK-677 | (ibutamoren OR "MK-677" OR "MK-0677") AND AREA[Phase]PHASE3 | 1 | NCT06948214 · n = 150 · Lumos Pharma Growth Hormone Deficiency (GHD) |
| GHRP-2 | ("GHRP-2" OR pralmorelin) AND AREA[Phase]PHASE3 | 0 | — |
| Hexarelin | (hexarelin) AND AREA[Phase]PHASE3 | 0 | — |
| Somatropin | (somatropin) AND AREA[Phase]PHASE3 | 183 | NCT05330325 · n = 412 · Novo Nordisk A/S SGA, Turner Syndrome, Noonan Syndrome, ISS |
| MGF | ("mechano growth factor") AND AREA[Phase]PHASE3 | 14 | NCT00125190 · n = 45 · Ipsen Insulin-Like Growth Factor-1 Deficiency, Growth Disorders |
| Mecasermin | (mecasermin) AND AREA[Phase]PHASE3 | 8 | NCT00330668 · n = 114 · Ipsen Growth Disorders |
| PEG-IGF-1 | ("PEG-IGF-1") AND AREA[Phase]PHASE3 | 0 | — |
Where the numbers don't add up
- 3 of the 7 don't have a single study registered on ClinicalTrials.gov. They are GHRP-2, Hexarelin, PEG-IGF-1. For GHRP-2 and hexarelin, this is the page's finding: both have indexed literature — 256 and 313 articles — and no registered trial. The molecule was studied; the treatment, not.
- MK-677 has 1 registered phase 3 trial, versus 183 for somatropin. It's the secretagogue with the most ground covered of any on this site — and even so, the gap to the recombinant hormone is two orders of magnitude.
- Mecasermin is the IGF that exists as a drug. 103 articles, 37 registered studies, 8 phase 3 — and no active registration. The IGF-1 LR3, which this site already flags as the riskiest of the group, is the version without any of that.
- PEG-IGF-1 barely exists as a term. 6 articles with the spelling in quotes and 0 studies. Whoever sells under this name is selling a name the literature barely uses.
In Brazil
I searched every active ingredient in the open data on registered medicines, downloaded on September 12, 2026 — 43,508 rows, counting only Active status.
The result is the whole page in one picture: somatropin has a registered product with a trade name, and the rest of the axis has nothing. Absence from the database doesn't mean prohibition — it means there is no legal product to buy with that active ingredient.
| Active ingredient | Search pattern | Active registrations | Declared therapeutic class | Products |
|---|---|---|---|---|
| MK-677 | IBUTAMOREN | 0 | — | — |
| GHRP-2 | PRALMORELIN | 0 | — | — |
| Hexarelin | HEXARELIN | 0 | — | — |
| Somatropin | SOMATROPINA | 9 | RECOMBINANT HUMAN GROWTH HORMONE | BIO-MANGUINHOS SOMATROPINA, BIOMATROP, CRISCY, EUTROPIN, GENOTROPIN, HORMOTROP |
| Mecasermin | MECASERMIN | 0 | — | — |
References
- Public ClinicalTrials.gov API, version 2 — the source for all the study and phase 3 counts on this page.
- PubMed E-utilities (esearch) — the basis for all article counts on this page.
- NCT06948214 registration on ClinicalTrials.gov — the only phase 3 ibutamoren trial the search returned, sponsored by Lumos Pharma.
- NCT00764699 registration on ClinicalTrials.gov — one of the registrations that the search for “mechano growth factor” returns, and which is actually about mecasermin.