CJC-1295 and sermorelin start from the same 29 amino acids, the active front end of growth-hormone-releasing hormone. Sermorelin is that fragment unchanged and was once sold as an approved drug. CJC-1295 is the same fragment with four substitutions and, in its original form, a chemical hook that ties it to albumin in the blood. The result is two molecules of almost the same weight whose measured lifetimes in the body differ by about two thousandfold. This page sets out each one's dose record (read 2026-10-05) and the syringe arithmetic. It compares; it recommends neither.
The single-compound records are on the CJC-1295 and sermorelin dosage pages; the two forms of CJC-1295 are separated on CJC-1295 DAC vs no DAC.
The two dose records
| Sermorelin | CJC-1295 | |
|---|---|---|
| Sequence | GHRH(1-29)-NH2, unchanged | GRF(1-29) with four substitutions; DAC form adds a lysine-maleimide group |
| Molecular weight | 3,357.9 (PubChem) | 3,647.2 for the DAC form (PubChem); no PubChem record for no-DAC |
| Regulatory record | Geref, NDA 020443, approved 1997, discontinued | No label, ever |
| Human dose record | 30 mcg/kg once daily at bedtime, growth-hormone-deficient children, up to a year | 30 to 90 mcg/kg per injection, healthy adults, single and repeated doses (DAC form only) |
| Half-life | 4.3 minutes (IV infusion) | 5.8 to 8.1 days, and 8 days (DAC); not published (no DAC) |
| Registry, 2026-10-05 | 27 intervention records | 1 record, terminated |
Jetté and colleagues, who named CJC-1295 in 2005, describe it as "a tetrasubstituted form of hGRF(1-29)" with the lysine derivative at the C terminus, and report it was "present in plasma beyond 72 h" in rats. The four substitutions without the albumin hook are what is sold as CJC-1295 no DAC or Mod GRF 1-29 — chemically, sermorelin with four residues changed.
The same per-kilogram figure appears in both records, on different clocks. Sermorelin's paediatric regimen was 30 mcg/kg every night (Thorner et al. 1996). Teichman's CJC-1295 study singled out 30 and 60 mcg/kg as the best tolerated, given as single injections or two to three doses a week or two apart. At 70 kg, 30 mcg/kg is 2.1 mg either way (arithmetic by this site) — once a night for sermorelin in its trial, once in a week or more for CJC-1295.
Minutes against days
| Molecule | Half-life or half-time | Source |
|---|---|---|
| GHRH(1-29)-NH2 (sermorelin's sequence) | 4.3 ± 1.4 minutes | Soule et al. 1994, IV infusion, 10 men |
| D-Ala2-GHRH(1-29)-NH2 (one substitution) | 6.7 ± 0.5 minutes | same study |
| CJC-1295 no DAC (four substitutions) | not published | — |
| CJC-1295 with DAC | 5.8 to 8.1 days; 8 days | Teichman 2006; Ionescu and Frohman 2006 |
The 1994 study is the only human measurement of what a substitution does on its own: one change, at position 2, lengthened the half-time from 4.3 to 6.7 minutes and lowered metabolic clearance by about half. That is minutes, not days. The multi-day figure belongs to the DAC form, whose albumin binding is what Jetté designed it for. Any half-life quoted for the no-DAC form has no human study behind it in the sources read.
The clock changes what the hormone does. Ionescu and Frohman measured growth hormone overnight in healthy men before and one week after 60 or 90 mcg/kg of CJC-1295 with DAC: the pulses kept their frequency and size, but trough GH rose 7.5-fold, mean GH 46% and IGF-I 45%. Sermorelin, cleared within minutes, has no comparable week-long measurement; its studied regimen was a nightly injection.
Weekly totals, and why mass is not the difference
| Source of the figure | Per injection | Frequency | Per week |
|---|---|---|---|
| Sermorelin, clinic pages | 200–500 mcg | once nightly | 1.4–3.5 mg |
| CJC-1295 with DAC, vendor pages | 1–2 mg, or 0.5–1 mg twice | weekly | 1–2 mg |
| CJC-1295 no DAC, vendor pages | 100–300 mcg | 1–3 times a day | 0.7–6.3 mg |
| CJC-1295 with DAC, Teichman study at 70 kg | 2.1–4.2 mg | single, or weekly to biweekly | up to 4.2 mg |
Weekly totals and per-injection figures come from this site's dosage pages (read 2026-09-18) and are multiplied out here. The ranges overlap: a week of clinic sermorelin and a week of vendor-stated DAC CJC-1295 are both a few milligrams. Mass for mass the molecule counts are close too — 1 mg of sermorelin is about 0.298 micromoles and 1 mg of CJC-1295 with DAC about 0.274 (arithmetic by this site from the PubChem weights) — so unlike a comparison with a five-residue secretagogue such as ipamorelin, equal micrograms here are nearly equal molecules. What separates the two is how long each molecule stays: three milligrams spread over seven nightly injections that clear in minutes is not the same exposure as two milligrams in one injection that lasts a week.
The arithmetic per vial
Units on a U-100 syringe = mcg ÷ concentration in mcg/mL × 100. Both peptides are sold as 5 mg and 10 mg powders; the reading depends only on the concentration.
| Amount | 2.5 mg/mL (5 mg + 2 mL) | 5 mg/mL (10 mg + 2 mL) |
|---|---|---|
| 100 mcg (no-DAC figure) | 4 units | 2 units |
| 200 mcg (sermorelin, lower clinic figure) | 8 units | 4 units |
| 300 mcg (either) | 12 units | 6 units |
| 500 mcg (sermorelin, upper clinic figure) | 20 units | 10 units |
| 1 mg (DAC, half of a twice-weekly figure) | 40 units | 20 units |
| 2 mg (DAC, weekly figure) | 80 units | 40 units |
The units are the same for either peptide at the same concentration; what the units mean over a week is not. A vial label that says only "CJC-1295" does not show which form it holds, and the reading is identical for both. The calculator's sermorelin, CJC-1295 and Mod GRF 1-29 settings handle any vial and volume; the formula is on the mg to units page.
What is not established
No trial compares CJC-1295 with sermorelin; ClinicalTrials.gov listed none naming both on 2026-10-05. The only CJC-1295 registration, a phase 2 study in people with HIV and visceral obesity (NCT00267527), was terminated without posted results. Sermorelin's labelled regimen was paediatric and its product is discontinued; the adult clinic figures are compounding conventions. The no-DAC form has no human pharmacokinetic study at all. Research vials sold under either name have no data of their own. The compounds are covered in Medibact's CJC-1295 guide and sermorelin guide. Nothing on this page is an instruction; dose and product belong with a clinician.
Sources and dates
Opened 2026-10-05: PubMed abstracts 15817669 (Jetté et al., Endocrinology 2005), 7962295 (Soule et al., JCEM 1994), 16352683 (Teichman et al., JCEM 2006) and 17018654 (Ionescu and Frohman, JCEM 2006); PubChem records for sermorelin (CID 16132413); ClinicalTrials.gov intervention searches for sermorelin, CJC-1295 and both together. The Geref record, the Thorner regimen, the CJC-1295 DAC molecular weight and the vendor and clinic figures are as recorded on this site's sermorelin, CJC-1295 and DAC vs no-DAC pages (2026-09-18 and 2026-09-27). Weekly totals, molecule counts and units are arithmetic by this site. Corrections go to the contact page.