These three peptides come up together constantly because they all do the same broad thing — prompt your body to release its own growth hormone. But they are not three versions of one idea. They split into two families based on which of two levers they pull, and that split is the key to the whole comparison.
The two levers
Your body triggers a growth-hormone pulse two ways: through the GHRH signal and through the ghrelin signal. Sermorelin and CJC-1295 copy the first; ipamorelin copies the second.
| Compound | Class (lever) | Half-life | Evidence base |
|---|---|---|---|
| Sermorelin | GHRH analog | Short (minutes) | Approved-drug history (Geref) |
| CJC-1295 | GHRH analog | Long (days, DAC form) | Human pharmacokinetic data |
| Ipamorelin | Ghrelin/GHS agonist | Short (~2 h) | Mostly preclinical |
- Sermorelin and CJC-1295 are both GHRH analogs — same lever, different duration. Sermorelin is the short, unmodified baseline1; CJC-1295 (DAC) is engineered to last for days2 (DAC vs no-DAC).
- Ipamorelin sits in a separate class, pulling the ghrelin/GHS lever — a different trigger on the same system3 (CJC-1295 vs ipamorelin).
What the studies actually found
The three don't just differ in mechanism — they differ sharply in how well each is evidenced:
| Study | Model | Key result | Year |
|---|---|---|---|
| Raun et al.3 | Rat, pig + cells (ipamorelin) | Selective growth-hormone release without a cortisol spike | 1998 |
| Prakash & Goa (review)1 | Human (sermorelin, pediatric) | Documented Geref as an approved diagnostic and treatment for childhood GH deficiency | 1999 |
| Teichman et al.2 | Human (CJC-1295 DAC) | One injection raised growth hormone 6+ days and IGF-1 9–11 days; half-life ~6–8 days | 2006 |
In plain terms: sermorelin actually worked as a medicine in people (for a narrow use), CJC-1295 has been measured in people, and ipamorelin's headline data is from animals. Same conversation, three very different evidence footings.
Why the split matters
Two GHRH analogs (sermorelin, CJC-1295) differ mainly in how long they last; ipamorelin differs in how it works.
- Sermorelin vs CJC-1295 is essentially a *half-life* question — same lever, short versus long.
- Either of them vs ipamorelin is a *mechanism* question — GHRH lever versus ghrelin lever.
That's also why the popular "CJC-1295 + ipamorelin" pairing exists: it deliberately combines the two different levers, not two versions of the same one.
The honest bottom line
The mechanisms are well described, but keep the evidence honest: sermorelin's real clinical pedigree was a narrow pediatric approval (since withdrawn commercially), CJC-1295's human data is pharmacokinetic (hormone levels, not proven outcomes), and ipamorelin is largely preclinical. None is a currently approved general growth-hormone medicine.
Deeper reading
What is sermorelin, what is CJC-1295, what is ipamorelin, and the growth-hormone secretagogues explainer.