GHRH analogs and GHRPs are mechanistically distinct compounds that both result in pituitary GH release — through different receptors that act synergistically. This page covers the two classes, their compounds, and why the combination approach is studied.
Research reference only. Not medical advice or dosing guidance.
Both stimulate pituitary GH release — via different receptors that converge downstream
GHRH analogs
Receptor: GHRHR (pituitary)
Mimic the hypothalamic signal that prompts pituitary somatotrophs to synthesize and release GH. DPP-4-resistant substitutions extend stability from the native ~7-minute half-life. The DAC addition to CJC-1295 further extends to ~7 days via albumin binding.
GHRPs (ghrelin-axis)
Receptor: GHS-R1a (pituitary + hypothalamus)
Act on the ghrelin receptor via a separate intracellular pathway. They amplify GH release synergistically when combined with a GHRH analog — the two receptor classes converge downstream. Ipamorelin is the most selective GHRP, releasing GH without meaningfully raising cortisol or prolactin.
Synergy: When a GHRH analog and a GHRP are combined, the downstream cAMP (GHRH pathway) and IP₃/Ca²⁺ (ghrelin pathway) signals converge on the same somatotroph, producing larger GH pulses than either alone. This is why CJC-1295 (no DAC) + ipamorelin is the most studied combination in the GH-secretagogue literature.
Sermorelin
GRF 1-29 · Geref
Shortest active GHRH fragment; historically the first GHRH analog FDA-approved (pediatric GH deficiency), later discontinued commercially.
CJC-1295 (no DAC)
Mod GRF 1-29
Four DPP-4-resistant substitutions extend stability vs sermorelin. The preferred pairing with ipamorelin for pulsatile GH research.
CJC-1295 (DAC)
CJC-1295 DAC
Albumin-binding DAC moiety extends half-life to ~a week. Studied for sustained IGF-1 elevation; blunts natural GH pulsatility.
Tesamorelin
Egrifta
Only currently FDA-approved GH-axis peptide. Approved for HIV-associated visceral lipodystrophy. Also studied for cognition and hepatic fat.
Ipamorelin
Most selective GHRP: GH release with minimal ACTH/cortisol/prolactin impact. Standard pairing with CJC-1295 (no DAC) in synergy research.
Hexarelin
More potent than ipamorelin but less selective. Distinctive CD36-mediated cardioprotective thread in preclinical literature, independent of GH release.
GHRP-2
Pralmorelin
Engineered from GHRP-6 for greater potency per dose, with markedly less of the acute hunger. Marketed in Japan as a single-injection test of pituitary GH reserve.
GHRP-6
The probe compound whose target hunt led to cloning GHS-R1a in 1996 and identifying ghrelin in 1999. The least selective of the family, and the reference when the appetite effect is the point.
MK-677
Ibutamoren
Not a peptide — an orally active small molecule at the same ghrelin receptor. Catalogued here for the shared mechanism: sustained GH and IGF-1 elevation, and a blunted pulse.
Endogenous GH is released in pulses — the largest occurring during deep sleep — and this pulsatility is functionally important for the GH/IGF-1 axis. Short-acting compounds (sermorelin, CJC-1295 no DAC, ipamorelin) reproduce this pulsatile pattern by producing brief receptor activation.
The DAC addition to CJC-1295 shifts the pharmacokinetic profile from pulsatile to sustained: albumin binding keeps the peptide in circulation for days, producing prolonged GHRHR occupancy. This raises baseline GH and IGF-1 but blunts the natural peak-to-trough rhythm. Whether blunting pulsatility is clinically consequential for the endpoints studied — body composition, IGF-1, fat distribution — is the central research question distinguishing the two CJC-1295 forms.
CJC-1295 vs ipamorelin — detailed comparisonWhether a licensed compounding pharmacy may legally prepare these substances — a separate question from FDA drug approval
The GH-axis peptides are the instructive counterexample to the healing peptides. While BPC-157 and TB-500 were moving off the safety-risk list in 2026, this class went the other way: FDA recommended against 503A inclusion for ipamorelin and CJC-1295, and its advisory committee agreed in late 2024. Ibutamoren, GHRP-2 and GHRP-6 remain on the Category 2 list. Anyone who has read that peptides were broadly deregulated has read about a different set of molecules.
Approved as Egrifta in 2010 for HIV-associated lipodystrophy. The compounding question does not arise in the same way for an approved product.
Approved as Geref in 1990 and later withdrawn from the market for commercial reasons. It does not appear on the current Category 2 list.
Reviewed on October 29, 2024. FDA recommended against inclusion and PCAC voted against adding ipamorelin to the 503A bulks list. Ipamorelin acetate remains in Category 2 for 503B outsourcing facilities.
FDA proposed that the CJC-1295 salts and free bases, with and without DAC, not be included on the 503A bulks list. PCAC voted against inclusion on December 4, 2024.
Covered by the same December 4, 2024 review and vote as the no-DAC form.
Remains in Category 2 for 503B outsourcing facilities on the current list.
Remains in Category 2 for 503B outsourcing facilities on the current list.
Listed as ibutamoren mesylate, and one of the few substances flagged for both 503A and 503B. It remains on the Category 2 list.
None of these statuses is FDA approval, and none establishes efficacy, dosing, or a benefit-risk profile. Legal 503A compounding requires FDA to place a substance on the bulks list through notice-and-comment rulemaking. That step had not been completed for any peptide on this page as of the review date.
Regulatory status reviewed
Side-by-side pages covering the compounds on this hub
CJC-1295 vs Ipamorelin
different receptors, synergistic outcome
CJC-1295 vs Sermorelin
same GHRH backbone, different duration
Ipamorelin vs Hexarelin
selectivity versus potency
MK-677 vs Ipamorelin
same receptor, oral-sustained versus injectable-pulsatile
Tesamorelin vs CJC-1295
the approved GHRH analog versus the research one
GHRP-2 vs GHRP-6
the potent successor versus the original
Ipamorelin vs GHRP-2
a clean signal versus a stronger one
Tesamorelin vs Sermorelin
full-length and current versus the truncated original
What is a growth hormone secretagogue?
A growth hormone secretagogue is any compound that stimulates the pituitary gland to release growth hormone (GH). The term covers two mechanistically distinct classes: GHRH analogs, which mimic hypothalamic growth-hormone-releasing hormone at the GHRHR receptor, and GHRPs (growth-hormone-releasing peptides), which act on the ghrelin receptor (GHS-R1a). Both classes are studied separately and in combination.
What is the difference between a GHRH analog and a GHRP?
GHRH analogs (sermorelin, CJC-1295, tesamorelin) bind the GHRH receptor on pituitary somatotrophs and prompt GH synthesis and release, mimicking the hypothalamic pulse. GHRPs (ipamorelin, hexarelin) bind the ghrelin receptor (GHS-R1a) via a separate intracellular pathway. The two classes act synergistically — combining them produces more GH release than either alone because the downstream pathways converge.
Why is CJC-1295 (no DAC) commonly paired with ipamorelin?
CJC-1295 (no DAC) provides a short GHRH-receptor signal; ipamorelin provides a simultaneous ghrelin-receptor signal. Together they converge on the same pituitary somatotroph and produce a larger, synergistic GH pulse than either alone. The short half-life of both compounds keeps the pulse physiologic rather than sustained — preserving natural GH pulsatility.
What is the difference between CJC-1295 with DAC and without DAC?
The DAC (Drug Affinity Complex) is a maleimidopropionic acid group that allows the peptide to bind covalently to serum albumin, extending half-life from ~30 minutes (no DAC) to ~6–8 days (DAC). The no-DAC form produces brief, pulsatile GH pulses. The DAC form produces sustained GH and IGF-1 elevation but blunts the natural pulsatility of the GH axis — a trade-off studied in body-composition and IGF-1 research.
What makes ipamorelin different from other GHRPs?
Ipamorelin is defined by its selectivity: it releases GH with minimal effect on ACTH, cortisol, or prolactin, unlike earlier GHRPs (GHRP-6, hexarelin) that raise these hormones alongside GH. This cleaner profile has made it the most studied GHRP in combination protocols. It is not FDA-approved.
Is tesamorelin FDA-approved?
Yes — tesamorelin (Egrifta) is the only currently FDA-approved GH-axis peptide in this catalog. It is approved for reduction of excess visceral abdominal fat in people with HIV-associated lipodystrophy. Other uses described here are research contexts, not approved indications.
Can a compounding pharmacy legally prepare ipamorelin or CJC-1295?
Not under section 503A. FDA recommended against including ipamorelin on the 503A bulks list and its advisory committee voted against it on October 29, 2024. The same happened for CJC-1295, in every salt and free-base form with and without DAC, on December 4, 2024. The stated concerns were insufficient human safety data, questions about unintended endocrine effects, and a lack of reproducible efficacy outside small or open-label studies. Ibutamoren, GHRP-2 and GHRP-6 remain on the Category 2 list of substances FDA considers to present significant safety risks.
Were GH peptides affected by the 2026 peptide reclassification?
Largely no, and this is the most common point of confusion. The substances removed from Category 2 in April 2026 and reviewed by the advisory committee that July were tissue-repair, longevity and neuropeptide compounds — BPC-157, TB-500, KPV, MOTS-c, semax, epitalon and others. The GH-axis peptides had already been reviewed and declined in late 2024. The two events are often reported as one trend; they are not.
How do GH secretagogues differ from injecting growth hormone directly?
Secretagogues prompt the pituitary to release the body's own GH, preserving the natural feedback loop (IGF-1 suppresses further GH release when levels rise). Direct GH injection bypasses this feedback. Whether preserving pulsatility and feedback is clinically meaningful depends on the indication and is an active research question. Secretagogues are studied partly because they are peptides that require pituitary integrity to work, while direct GH does not.
Research reference only. Except for tesamorelin (Egrifta, specific indication only), none of the compounds on this page are FDA-approved. Nothing here constitutes medical advice, dosing guidance, or an offer for sale.