Bottom line
Modified GRF(1-29) is a synthetic 29-amino-acid GHRH analog with four amino-acid substitutions (D-Ala², Gln⁸, Ala¹⁵, Leu²⁷) designed to reduce enzymatic degradation. It is the core peptide sequence of CJC-1295 but lacks the Drug Affinity Complex (DAC) albumin-binding modification. No published human study has evaluated this specific non-DAC variant, and its human pharmacokinetics have not been established. The approximately 6–8-day half-life reported for DAC-conjugated CJC-1295 must not be transferred to the non-DAC substance. No approved human drug product or clinical trial of this distinct variant was identified.
Identity and composition
| Field | Verified information |
|---|---|
| Preferred name | Modified GRF(1-29) |
| Key aliases | CJC-1295 without DAC, Mod GRF(1-29), tetrasubstituted GRF(1-29), CJC-1295 no DAC |
| Molecular/sequence identity | 29-residue synthetic peptide: Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-NH2 |
| Modifications/form | Four substitutions vs. native GHRH(1-29): D-Ala² (L→D isomer), Gln⁸ (Asn→Gln), Ala¹⁵ (Gly→Ala), Leu²⁷ (Met→Leu); C-terminal amidation |
| Stable identifiers | PubChem CID: 56841945; CAS: 863288-34-0 (free base); MW ~3368 Da |
| Identity caveats | Commonly misrepresented. Marketed as "CJC-1295" with no DAC qualifier, leading purchasers to falsely attribute the 6–8 day half-life from Teichman et al. (DAC form) to this compound. No published human data exist for this specific variant. The sequence is identical to the backbone of CJC-1295 without the C-terminal Lys-maleimide DAC handle. PubChem CID 56841945 is manually cited in this monograph but excluded from the automatic single-compound asset resolver because the name "Modified GRF (1-29)" is ambiguous with the CJC-1295 DAC form. The systematic title at PubChem (L-Tyr-D-Ala-L-Asp-L-Ala-...) confirms the sequence. No automatic structure asset. |
Development and approval status
| Jurisdiction | Status and indication | Product/source | As of |
|---|---|---|---|
| US (FDA) | No regulatory status; sold as research chemical | — | 2026-08-06 |
| Any jurisdiction | No clinical development or approval | — | 2026-08-06 |
Mechanism and pharmacology
By sequence and peptide class, Modified GRF(1-29) is expected to act as a GHRH-receptor agonist and stimulate GH release through cAMP-dependent signaling. The substitutions were intended to reduce known degradation pathways, including N-terminal DPP-IV cleavage. These properties are mechanistic inferences for the standalone non-DAC substance, not results from a human pharmacology study of it. Jetté et al. studied three albumin-binding maleimido hGRF derivatives, including CJC-1295, in rat pituitary cells and rats; they did not separately administer the standalone non-DAC free base. FDA's 2024 review likewise found no pharmacology, pharmacokinetic, or toxicokinetic study of the CJC-1295 free-base or acetate forms. A defensible human half-life for Modified GRF(1-29) therefore cannot be stated from the published CJC-1295 DAC evidence.
Evidence by claim
| Claim/indication | Stage | Grade | Best human evidence | Main result | Important limitations |
|---|---|---|---|---|---|
| GH release (any formulation) | Preclinical | D | No human data for this exact variant | No adequate human evidence | All human data for the DAC conjugate; backbone variant never studied in humans |
| Body composition | Marketing | E | No evidence | No adequate human evidence | Claims extrapolated from DAC study or from other GHRH analogs |
| Synergy with GHRPs | Marketing | E | No evidence | No adequate human evidence | Community practice without clinical support |
Key studies
| Study | Design/population | Exposure studied | Endpoints and result | Limitations |
|---|---|---|---|---|
| Jetté et al., Endocrinology 2005; PMID: 15817669 | Preclinical experiments in rat anterior-pituitary cells and normal male Sprague-Dawley rats | Three maleimido hGRF derivatives designed to conjugate to albumin; CJC-1295 was given once SC at 1 micromol/kg in the rat experiment | CJC-1295 produced an approximately fourfold greater GH AUC than native hGRF over 2 hours, remained detectable in plasma beyond 72 hours, and generated albumin-bound species detected from 15 minutes to beyond 24 hours | Tested the DAC-containing derivative; it did not isolate or establish PK, safety, or efficacy for standalone Modified GRF(1-29) |
No human study has administered the non-DAC tetrasubstituted GRF(1-29) as a distinct compound.
Dose and administration evidence
Approved labeled regimen
Not applicable.
Studied regimens (not recommendations)
No established or recommended human dose. No human study has established a dose for this specific variant.
What is not established
No human pharmacokinetic data
No effective dose range
No safety data
No efficacy data
Safety
No human safety data exist for this compound. Theoretical risks are similar to those of other GHRH analogs: injection-site reactions, transient GH/IGF-1 elevation effects, and the theoretical risk of sustained IGF-1 elevation promoting neoplasia. Research-grade material is of unverified purity and identity.
Unknowns and product-quality risks
All safety, pharmacokinetic, and efficacy parameters are unknown. Products sold as "CJC-1295 without DAC" or "Modified GRF(1-29)" cannot be assumed to match a characterized clinical material. Vendor certificates do not establish regulator-reviewed identity, sterility, potency, or suitability for human use.
Interactions and special populations
No human data exist.
Regulatory, compounding, and sport notes
Modified GRF(1-29) is structurally a GHRH analog and falls within WADA's prohibited category S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics). It is detectable by LC-MS/MS if the specific sequence is targeted.
Evidence gaps
No published human study of any kind
No direct pharmacokinetic data identified for the non-DAC variant alone
No toxicology data
No regulatory dossier
The compound exists almost entirely in the gray market without published scientific support for its isolated use
Search notes
Databases and registries: PubMed, ClinicalTrials.gov, Google Scholar
Search terms: "modified GRF 1-29", "tetrasubstituted GRF", "CJC-1293", "CJC-1295 without DAC"
Last searched: 2026-08-06
Inclusion emphasis: Any peer-reviewed primary data for this specific variant
Sources
Jetté L et al. Identification of CJC-1295 as a long-lasting GRF analogue. Endocrinology. 2005;146(7):3052-3058. https://pubmed.ncbi.nlm.nih.gov/15817669/
PubChem CID 56841945. Modified GRF(1-29). https://pubchem.ncbi.nlm.nih.gov/compound/56841945
Teichman SL et al. Prolonged stimulation of GH and IGF-I by CJC-1295 (DAC form). J Clin Endocrinol Metab. 2006. https://pubmed.ncbi.nlm.nih.gov/16352683/ (Background only — does not apply to non-DAC variant.)
WADA Prohibited List 2026. https://www.wada-ama.org/en/prohibited-list
FDA. Pharmacy Compounding Advisory Committee briefing document: CJC-1295-related bulk drug substances. 2024. https://www.fda.gov/media/183819/download