Editorial note: this article summarises published research on CJC-1295 and ipamorelin. Baclabs does not sell CJC-1295, ipamorelin or any peptide; we supply bacteriostatic water and reconstitution consumables. Nothing here is medical advice.
The “cjc 1295 dac vs no dac” question comes up because two very different molecules share a name. CJC-1295 with DAC is a long-acting growth hormone-releasing hormone (GHRH) analogue with a half-life measured in days, studied in two placebo-controlled human trials. CJC-1295 no-DAC, also sold as Mod GRF 1-29, is the same peptide sequence without the albumin-binding group, which makes it a short-acting GHRH analogue with no published human trials of its own.
Ipamorelin is a different class of compound altogether: a ghrelin-receptor agonist. It is usually paired with one form of CJC-1295 on the argument that a GHRH analogue and a ghrelin agonist together release more growth hormone (GH) than either alone. This article sets out what each compound is, what the human data show, and why the FDA moved against both in 2023. The wider context is in our growth hormone secretagogues pillar.
CJC-1295 with DAC: what the human trials showed
CJC-1295 is a tetrasubstituted analogue of GHRH(1-29)-NH2, the 29-amino-acid fragment that is also the basis of sermorelin. Four amino acid substitutions make the peptide resistant to the enzymes that clear native GHRH within minutes. The “DAC” (drug affinity complex) is a lysine linker carrying a maleimidoproprionic acid group that binds covalently to cysteine-34, the single unpaired cysteine on serum albumin. Once attached, the peptide circulates with albumin and is cleared at albumin’s pace [1].
Teichman and colleagues reported two randomised, placebo-controlled, double-blind studies in healthy adults aged 21 to 61, lasting 28 to 49 days. After a single subcutaneous injection, mean plasma GH rose 2- to 10-fold for six days or more and IGF-1 rose 1.5- to 3-fold for 9 to 11 days, in a dose-dependent manner. The estimated half-life was 5.8 to 8.1 days. With repeated weekly or fortnightly dosing there was a cumulative effect, and mean IGF-1 stayed above baseline for up to 28 days. No serious adverse reactions were reported; the drug was described as relatively well tolerated, particularly at 30 or 60 mcg/kg [1].
A second study by Ionescu and Frohman sampled blood every 20 minutes overnight in healthy men before and one week after 60 or 90 mcg/kg. The frequency and magnitude of GH pulses were unchanged. What changed was the floor: trough GH rose about 7.5-fold, lifting mean GH by 46 per cent, and IGF-1 rose 45 per cent. The IGF-1 rise did not correlate with pulse measures, which suggests it was the raised basal GH that drove it [2].
Those two papers are the entire human evidence base. They report no body composition, strength, sleep or clinical outcome, and the compound was never taken further. Trial doses were weight-based (30–90 mcg/kg, roughly 2–7 mg for an 80 kg adult) and given weekly or fortnightly, not daily.
CJC 1295 DAC vs no DAC: the same sequence, days versus minutes
Remove the linker and the albumin binding and what is left is the tetrasubstituted GRF(1-29) peptide itself. Vendors call this CJC-1295 no-DAC or Modified GRF 1-29. It still resists enzymatic cleavage better than sermorelin, but without albumin binding it is cleared quickly, so its action lasts a matter of minutes to a short number of hours rather than days. We could find no peer-reviewed human pharmacokinetic study published under either name, so the half-life figures quoted online are extrapolations from native GHRH and from the Teichman data, not measurements.
The DAC form therefore produces a sustained rise in basal GH and IGF-1 that persists for weeks and cannot be stopped quickly. The no-DAC form produces a short GH pulse timed to the injection, closer to the physiological pattern, and is the form usually combined with a GHRP.
| CJC-1295 with DAC | CJC-1295 no-DAC (Mod GRF 1-29) | Ipamorelin | |
|---|---|---|---|
| Receptor | GHRH receptor | GHRH receptor | Ghrelin receptor (GHS-R1a) |
| Half-life | 5.8–8.1 days [1] | Not published; short | About 2 hours (IV, healthy volunteers) [4] |
| Effect on GH | Raised basal GH for 6+ days, pulses preserved [1][2] | Short pulse after each dose (inferred) | Pulse; selective for GH over ACTH/cortisol in animals [3] |
| Human trials | Two RCTs in healthy adults [1][2] | None under this name | PK study; failed phase 2 in ileus [4][5] |
| FDA compounding status | Category 2 (Sept 2023); nomination later withdrawn [6] | Not separately listed | Category 2 for 503B [6][7] |
Ipamorelin: the selective GHRP
Ipamorelin is a pentapeptide developed by Novo Nordisk in the 1990s as an agonist of the growth hormone secretagogue receptor GHS-R1a, the ghrelin receptor. Earlier GHRPs (GHRP-6, GHRP-2, hexarelin) release ACTH, cortisol and prolactin alongside GH; ipamorelin was designed to avoid this.
In Raun and colleagues’ 1998 paper, ipamorelin released GH from rat pituitary cells and in anaesthetised rats and conscious swine. In swine its potency (ED50 2.3 nmol/kg) was similar to GHRP-6 (3.9 nmol/kg) and lower than GHRP-2 (0.6 nmol/kg). Both GHRP-6 and GHRP-2 raised plasma ACTH and cortisol; ipamorelin did not, even at 200 times its GH-releasing ED50, releasing no more ACTH or cortisol than GHRH itself. None of the compounds affected prolactin, FSH or LH in that model. The authors called it “the first GHRP-receptor agonist with a selectivity for GH release similar to that displayed by GHRH” [3].
That is an animal study. Human data amount to a pharmacokinetic and pharmacodynamic study in healthy volunteers using five escalating intravenous infusion rates, which reported a half-life of about two hours [4], and a phase 2 trial in patients recovering from bowel resection, where 0.03 mg/kg intravenously twice daily for up to seven days was well tolerated but showed no significant difference from placebo [5]. No controlled human trial of subcutaneous ipamorelin for body composition, sleep or recovery has been published.
Why the two are combined: synergistic GH pulsing
The rationale for pairing a GHRH analogue with a GHRP comes from older work with GHRP-6. In healthy subjects GHRP-6 alone releases more GH than GHRH alone, and given together the response is larger than the sum of the two. In patients with hypothalamic–pituitary disconnection, the GHRP-6 response and the synergy both disappeared while the GHRH response remained, which showed that GHRP-6 acts mainly at the hypothalamus, probably by releasing endogenous GHRH and opposing somatostatin [8]. A GHRH analogue supplies the direct pituitary signal; a GHRP amplifies it from above.
No published trial has tested the CJC-1295 plus ipamorelin combination against either component or placebo. The synergy is inferred from GHRP-6 and native GHRH. Vendor blends sold under names such as PULSE, typically CJC-1295 no-DAC and ipamorelin in a single vial, fix the ratio between the two and have no trial data of their own.
Regulatory position: the 2023 FDA Category 2 listing
On 29 September 2023 the FDA added a group of peptides, including CJC-1295 and ipamorelin acetate, to Category 2 of its interim lists of bulk substances nominated for compounding, the category for substances that “may present significant safety risks” and cannot be compounded. For CJC-1295 the agency cited immunogenicity risk for certain routes, complexities with peptide-related impurities and characterisation, and serious adverse events including increased heart rate and systemic vasodilatory reaction. For ipamorelin it cited aggregation and impurity-related immunogenicity risk, unnatural amino acids that complicate characterisation, and a published report of serious adverse events including death when the drug was given intravenously for gastric motility [6].
The 503A nominations for both were subsequently withdrawn by their nominators, and the FDA’s advisory committee took up CJC-1295-related substances in December 2024 [9]. As of the March 2025 list, ipamorelin acetate remains in Category 2 for 503B outsourcing facilities [7]. In the UK neither compound has ever been licensed, and products sold as “research chemicals” fall outside the Human Medicines Regulations only while they are not supplied for human use.
Reconstitution and diluent
Both peptides are sold as lyophilised powder in 2 mg or 5 mg vials. Because a vial is drawn from many times, a preserved diluent is appropriate: bacteriostatic water contains 0.9 per cent benzyl alcohol and supports multi-dose use for up to 28 days after first puncture (see storage and shelf life). The trade-offs against sterile water are covered in bacteriostatic water vs sterile water.
The formula is concentration = peptide mass ÷ diluent volume. On a U-100 insulin syringe each unit is 0.01 mL. A 2 mg ipamorelin vial with 2 mL of bacteriostatic water gives 1 mg/mL = 1,000 mcg/mL, so each unit holds 10 mcg and 100 mcg is 10 units. A 5 mg CJC-1295 vial with 2.5 mL gives 2,000 mcg/mL, or 20 mcg per unit. Full tables for both vial sizes are in reconstituting GHRPs and GHRHs.
Multi-dose vials need a preserved diluent. Baclabs supplies UK-stocked bacteriostatic water in 30 mL vials; see the reconstitution guide for the maths.
Frequently asked questions
What is the difference between CJC-1295 DAC and no DAC?
Both are the same tetrasubstituted GHRH(1-29) sequence. The DAC version carries a maleimidoproprionic acid linker that binds serum albumin, giving a half-life of 5.8 to 8.1 days and sustained GH and IGF-1 elevation [1]. The no-DAC version (Mod GRF 1-29) lacks the linker, is cleared quickly and produces a short GH pulse per dose.
Does ipamorelin raise cortisol?
In the 1998 animal study it did not: ipamorelin released no more ACTH or cortisol than GHRH, even at 200 times its GH-releasing dose, whereas GHRP-6 and GHRP-2 raised both [3]. That selectivity has not been formally tested in a controlled human trial, so the human answer is “probably not, on limited evidence”.
Is CJC-1295 ipamorelin FDA approved?
No. Neither compound has ever been approved as a medicine anywhere. In September 2023 the FDA placed both in Category 2 of its compounding bulks lists, citing safety concerns, which bars US compounding pharmacies from preparing them [6]. Ipamorelin remains in Category 2 for 503B facilities on the March 2025 list [7].
What dose of CJC-1295 was used in the human trials?
The Teichman trials used weight-based single and repeated doses, with 30 and 60 mcg/kg described as well tolerated; Ionescu and Frohman used 60 or 90 mcg/kg [1][2]. Dosing was weekly or fortnightly because of the long half-life. No human trial has established a dose for the no-DAC form or for ipamorelin by subcutaneous injection.
How long does CJC-1295 ipamorelin take to work?
For the DAC form, GH rose within the first day and stayed elevated for six or more days after one injection, and IGF-1 was raised for 9 to 11 days [1]. Ipamorelin’s GH pulse follows the injection and its half-life is about two hours [4]. No trial has measured time to any body-composition outcome.
References
- Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. Teichman et al., Journal of Clinical Endocrinology & Metabolism, 2006
- Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. Ionescu & Frohman, Journal of Clinical Endocrinology & Metabolism, 2006
- Ipamorelin, the first selective growth hormone secretagogue. Raun et al., European Journal of Endocrinology, 1998
- Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Gobburu et al., Pharmaceutical Research, 1999
- Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Beck et al., International Journal of Colorectal Disease, 2014
- Certain bulk drug substances for use in compounding may present significant safety risks. US FDA, 2023 (updated)
- Bulk drug substances nominated for use in compounding under section 503B. US FDA, updated March 2025
- Blocked GHRP-6-induced GH secretion and absence of the synergic action of GHRP-6 plus GHRH in patients with hypothalamopituitary disconnection. Journal of Clinical Endocrinology & Metabolism, 1995
- Pharmacy Compounding Advisory Committee meeting, December 4, 2024: bulk drug substances under evaluation for the 503A bulks list. US FDA, 2024
Disclaimer: This content is for educational purposes only and does not constitute medical advice. Bacteriostatic water is supplied for reconstitution of substances intended for research and for use as directed by a healthcare professional. Peptides and medicines discussed here may be unlicensed in the UK or prescription-only; consult a qualified clinician before using any medicine. Baclabs does not sell peptides.