Short answer: Sermorelin is GRF 1-29, the first 29 amino acids of GHRH.1 CJC-1295 is the same backbone with four amino acids swapped for stability; the DAC version also binds albumin, giving a 5.8 to 8.1 day half-life in healthy adults.23 The version without DAC (Mod GRF 1-29) has no published human studies.4 Sermorelin was once FDA approved; CJC-1295 never was.
| Sermorelin | CJC-1295 without DAC | CJC-1295 with DAC | |
|---|---|---|---|
| What it is | GHRH(1-29)-NH21 | GRF 1-29 with four amino-acid substitutions (Mod GRF 1-29)4 | The same substituted GRF 1-29 plus a reactive lysine that binds albumin2 |
| Approval status | Formerly approved as Geref; withdrawn 2009, not for safety5 | Never approved4 | Never approved4 |
| Human studies | Used in children with GH deficiency as Geref; IV clearance study in 10 men51 | No peer-reviewed human studies4 | Two dose-ranging trials in healthy adults and a GH-pulse study36 |
| Half-life | About 4.3 minutes (IV)1 | Not reported in humans4 | 5.8 to 8.1 days3 |
| Effect after one dose | Short GH pulse (minutes-long signal) | Not measured in humans | GH up 2- to 10-fold for 6 days or more; IGF-1 up 1.5- to 3-fold for 9 to 11 days3 |
| Doses studied | Geref label doses not confirmed in an available source | None in published human studies | 30 to 250 mcg/kg under the skin in healthy adults3 |
| FDA compounding note | Not on FDA's Category 2 or nominated-but-withdrawn lists7 | CJC-1295 is on the nominated-but-withdrawn list; FDA cites reports of increased heart rate and a systemic vasodilatory reaction7 | Same FDA entry for CJC-12957 |
| Sport | WADA S2.2.4 (named)8 | WADA S2.2.4 (CJC-1295 named)8 | WADA S2.2.4 (CJC-1295 named)8 |
GRF 1-29 is broken down within minutes. In a 1994 study in 10 men, its half-time during an IV infusion was 4.3 minutes, and swapping a single amino acid (D-alanine at position 2) slowed clearance and lengthened the half-time to 6.7 minutes.1 CJC-1295 goes further with four substitutions meant to resist breakdown by enzymes.4 The DAC version adds a reactive group that attaches to albumin in the blood; in rats it was still present in plasma beyond 72 hours.2 In humans, that version had a half-life of 5.8 to 8.1 days.3
No study has compared CJC-1295 and sermorelin directly. These are study protocols, not personalized advice; confirm any dosing with your prescriber.
CJC-1295 is on FDA's list of compounding bulk substances that were previously in Category 2 and were then withdrawn by their nominators. FDA's entry notes immunogenicity risk, serious adverse events including increased heart rate and a systemic vasodilatory reaction, and limited clinical data.7 Sermorelin does not appear on that page.7