Choose any two compounds below to see them side by side. Each comparison page lines up the level of evidence behind each one, the registered clinical trials, and where each stands with regulators, so the differences are easy to see in one place.
This is a side-by-side of what is documented, not a ranking. Different compounds are studied for different things, in different people, at different amounts. A row that looks stronger for one compound does not make it the better choice for anyone.
| Hexarelin | MK-677 | |
|---|---|---|
| Highest evidence tier on the page | E1 Approved-label evidence FDA or EMA approved labelling for a specific indication. | E1 Approved-label evidence FDA or EMA approved labelling for a specific indication. |
| Regulatory status | Not stated | Not stated |
| Research area | Growth hormone axis | Growth hormone axis |
| Regulator-approved dose on file | No approved dose | No approved dose |
| Molecular formula | C47H58N12O6 | C27H36N4O5S (free base, per PubChem's "Ibutamoren" entry). Some sources report the mesylate salt form as C28H40N4O8S2. |
| Molar mass | Approximately 887.06 g/mol (free base). | Approximately 528.67 g/mol (free base). |
| CAS number | 140703-51-1 (free base, consistently cited across Biosynth, Santa Cruz Biotechnology, GlpBio, and ChemicalBook). A separate CAS number, 208251-52-9, applies to the acetate salt form ("hexarelin acetate"), per Cayman Chemical and other vendor listings — this is a distinct salt registration, not a conflicting identifier for the same substance. | 159634-47-6 is consistently cited as the CAS number for ibutamoren free base. A separate number, 159752-10-0, is cited by some vendors (e.g., MedKoo) for "ibutamoren mesylate"; whether every source correctly distinguishes the free base from the mesylate salt in its own labeling was not fully verified in this research pass. |
| Registered trials on this site | None linked yet | None linked yet |
| What is not known | This session could not independently retrieve the exact numeric doses used in the published human dose-response studies of hexarelin (for example, the studies associated with PubMed IDs 7957536, 8954038, and 7962341) from the primary articles during this research pass; the specific figures should be confirmed... | This session could not fully resolve the apparent duplication or salt/isotope distinctions across the multiple PubChem CIDs associated with "ibutamoren" and "ibutamoren mesylate." The exact doses used across MK-677's full multi-decade clinical trial history, including the specific doses used in the pediatric LUM-201 program, were... |
Full pages: Hexarelin and MK-677. See also the clinical trial tracker and how we grade evidence.
Educational reference, not medical advice. Trial data from ClinicalTrials.gov. Everything else is drawn from the compound pages on this site, each of which cites its sources.
Most requested comparisons
These are the pairings readers look for most often. Each opens a full side-by-side page.
Weight management compounds
- Retatrutide vs Tirzepatide
- Semaglutide vs Tirzepatide
- Retatrutide vs Semaglutide
- Retatrutide vs Survodutide
- Cagrilintide vs Semaglutide
- Orforglipron vs Semaglutide
- Mazdutide vs Tirzepatide
- Cagrilintide vs Eloralintide
- LY4086940 vs Retatrutide
- LY4086940 vs Orforglipron
Growth hormone related peptides
- Ipamorelin vs Sermorelin
- Sermorelin vs Tesamorelin
- CJC-1295 (no DAC) vs Ipamorelin
- CJC-1295 with DAC vs Ipamorelin
Repair and recovery
Longevity, mitochondria and brain
How to read a comparison
A side-by-side table can make two compounds look equally proven when they are not. Keep these points in mind as you read.
- Evidence level matters more than the headline. Every compound is placed on the same six-tier scale, from published human clinical trials down to community reports. A compound with large human trials and one with only animal studies are not comparable, even when both appear in the same table.
- Registered trials show what is being tested. A trial listed on ClinicalTrials.gov tells you a question is being studied, not that the answer is known. Check the status and phase. You can browse every tracked study on the clinical trial tracker and see recent registry updates in the trial changes feed.
- Regulatory status is specific to a formulation and a country. Approval of one product does not mean every version of that compound is approved.
- Different populations and doses limit direct comparison. Results from separate trials, run in different people over different periods, cannot be lined up as if they came from a head-to-head study unless a comparison page says a head-to-head study exists.
Frequently asked questions
Which compound is better?
These pages do not rank compounds or tell anyone what to use. They show what the published and registered evidence says about each one so you can see where the evidence is strong and where it is thin.
Why are some comparisons mostly empty on one side?
Many popular peptides have little or no human trial data. When that is the case, the comparison says so plainly rather than filling the gap with community claims.
Can I compare doses here?
Reported amounts are documented on each individual peptide page, with the source and evidence tier for every figure. If you need to work out concentrations, the reconstitution calculator is a math tool only and does not suggest an amount.
Where can I see every compound?
The full peptide library lists every entry,.
PeptideBlog is an educational reference compiled from public sources. It is not medical advice, and nothing here is a recommendation for or against any compound.
