Your pituitary releases growth hormone in pulses — biggest pulse during deep slow-wave sleep, smaller ones scattered through the day. GH secretagogues work by stimulating those pulses. They don’t create GH from nothing; they push on the pituitary harder. That distinction matters because your age and pituitary health set the ceiling. A secretagogue can’t take you higher than that ceiling. Exogenous HGH can.
The GH axis has two receptor arms. The GHRH receptor responds to growth hormone releasing hormone and its analogs (CJC-1295, Sermorelin, Tesamorelin). The ghrelin receptor (GHS-R1a) responds to ghrelin and its mimetics (Ipamorelin, GHRP-2, GHRP-6). Hitting one arm produces a GH pulse. Hitting both arms simultaneously produces a substantially larger one — which is why the CJC + Ipamorelin combination became the standard injectable protocol.
This post maps the full lineup so you can pick the right tool.
The lineup
- CJC-1295 — synthetic GHRH analog; DAC version extends half-life to ~8 days, no-DAC version is pulsatile
- Ipamorelin — ghrelin-receptor agonist, highly selective; no prolactin, no cortisol elevation
- Sermorelin — the first 29 amino acids of native GHRH; mildest GHRH analog, best sleep signal
- Tesamorelin — full-length stabilized GHRH; only secretagogue studied for visceral fat in a clinical trial
- CJC-1295 + Ipamorelin (blend) — pre-mixed dual-receptor protocol in a single vial
- HGH — 191-amino-acid pituitary hormone; bypasses the pituitary rate-limit entirely
CJC-1295
CJC-1295 is a GHRH analog that binds the GHRH receptor on pituitary somatotrophs and triggers a GH pulse. The DAC distinction matters most: the Drug Affinity Complex version binds to circulating albumin, extending its active life to roughly eight days and producing sustained GH elevation from a single weekly injection. The no-DAC version (Modified GRF 1-29) has a half-life of about 15–30 minutes — a sharp, discrete pulse timed to the injection window.
No-DAC dosing: 150–300 mcg subcutaneously up to three times daily. With-DAC: 1–2 mg subcutaneously once per week. Both must be injected fasted — elevated insulin raises somatostatin, which blunts GH release. Side effects are water retention, possible joint stiffness, and elevated fasting glucose; monitor fasted glucose weekly. CJC-1295 appears on the FDA’s Section 503a restricted list and is prohibited under WADA.
Ipamorelin
Ipamorelin is a pentapeptide ghrelin-receptor agonist — an entirely different pathway from GHRH-receptor agonists. Unlike GHRP-2 and GHRP-6, Ipamorelin does not meaningfully raise prolactin, cortisol, or ACTH, and produces only minimal hunger stimulation at standard doses. That selectivity is what makes it the preferred ghrelin-arm agonist in modern protocols.
The saturation dose per injection is around 125–150 mcg — more doesn’t produce proportionally more GH because the ghrelin receptor is already at ceiling for that pulse. Standard dosing: 150–300 mcg subcutaneously up to three times daily, fasted, before bed or pre-workout. GH pulse occurs within 15–30 minutes. Combine with a GHRH-receptor agonist to cover both arms of the axis.
Sermorelin
Sermorelin is the first 29 amino acids of native GHRH — the minimum sequence required to activate the GHRH receptor. Same mechanism as CJC-1295, milder potency. Its clearest use case is sleep quality: the largest natural GH pulse occurs during slow-wave sleep, and Sermorelin before bed amplifies it — users report deeper sleep and better next-day recovery. Dosing: 150–300 mcg subcutaneously before bed, fasted. Side effects mirror the CJC-1295 profile at lower intensity: water retention, possible joint stiffness, elevated glucose.
As of this writing, Sermorelin is not on the FDA’s Section 503a restricted list, unlike CJC-1295, Ipamorelin, and MK-677 — one of the few GHRH-axis secretagogues still accessible through compounding pharmacies. Pair it with melatonin before bed to further amplify the nocturnal GH pulse.
Tesamorelin
Tesamorelin is a stabilized analog of full-length GHRH (44 amino acids), modified at the N-terminus to increase stability and extend half-life. It is the strongest injectable GHRH-receptor agonist, and the only GH secretagogue with an FDA-approved indication: visceral fat reduction in HIV-positive patients on antiretroviral therapy (trade name Egrifta).
The visceral fat reduction is indirect — Tesamorelin itself has no direct lipolytic activity; the fat loss comes from the GH it drives the pituitary to release. Tesamorelin and exogenous HGH are the only two compounds formally studied and shown to reduce visceral fat accumulation.
Dosing: 1–2 mg subcutaneously once or twice daily, fasted. Best stacked with Ipamorelin to cover both receptor arms. Cost: $10–$36/day — significantly more than Chinese generic HGH for equivalent output. Tesamorelin is the right choice when the FDA-studied visceral fat evidence matters or when a legal prescription route is required. Like Sermorelin, it is not on the FDA Section 503a restricted list.
CJC-1295 + Ipamorelin (the blend)
A single pre-mixed vial of no-DAC CJC-1295 (Mod GRF 1-29) and Ipamorelin at a fixed ratio. Activating both receptor arms simultaneously produces a substantially larger GH pulse than either compound alone, and no separate purchase is needed.
Dosing: 100–300 mcg subcutaneously one to three times daily, fasted. The trade-off versus buying them separately: the fixed ratio prevents independent dose titration. If water retention from the CJC component is a problem, you need separate vials to adjust. Blood glucose monitoring (fasted weekly) and Berberine (500–2000 mg/day) apply here as with standalone CJC-1295. Note: the blend uses no-DAC CJC — for once-weekly convenience, buy with-DAC CJC-1295 separately.
HGH itself
Human growth hormone is the 191-amino-acid peptide the pituitary naturally produces. Exogenous HGH bypasses the pituitary rate-limit entirely — the dose is fully controlled by what you inject. It drives lipolysis via hormone-sensitive lipase, upregulates IGF-1 in the liver, accelerates collagen synthesis, and improves skin texture and tissue density.
GH secretion declines roughly 85% from puberty peak by age 55. Secretagogues can partially compensate in younger users; in older users, the pituitary simply can’t produce enough GH for the secretagogue stimulus to move the needle — which is the practical argument for shifting to exogenous HGH.
SubQ only — not intramuscular. For fat loss, inject 60–90 minutes before fasted cardio (SubQ peak at 90–120 minutes post-injection). For muscle and anabolism, before bed aligns with the nocturnal GH peak and gives an 8–10 hour active window. WHO standard: 1 IU = 0.33 mg; 1 mg = 3 IU. Standard reconstitution: 1 mL BAC water per 10 IU vial = 10 IU/mL; 0.1 mL on a U-100 syringe = 1 IU.
How they compare
CJC-1295, Sermorelin, and Tesamorelin all hit the same receptor. The differences are potency, half-life, and what the clinical literature supports: Sermorelin is mildest; Tesamorelin is strongest with the only visceral fat evidence; CJC-1295 sits in between with the unique once-weekly DAC option.
The pituitary rate-limit applies equally to all secretagogues. Most users realistically see 1–2 IU equivalent from an optimized stack — meaningful for recovery, sleep quality, and modest body composition improvement, but a ceiling you can’t push through without switching to exogenous HGH.
On side effects: GHRP-2 and GHRP-6 elevate prolactin and cortisol and cause significant hunger — why those older ghrelin agonists have been replaced by Ipamorelin. Water retention and blood glucose elevation are shared risks across all GHRH analogs.
The stack picks
- Entry-level / sleep focus: Sermorelin 200–300 mcg before bed, fasted. Add melatonin before bed to amplify the nocturnal pulse. Mildest profile, still prescribable.
- Most popular injectable: CJC-1295 + Ipamorelin blend, before bed or pre-workout, fasted. Dual-receptor, one vial, well-established.
- Convenience first: CJC-1295 with DAC at 1–2 mg once weekly + oral MK-677 (20–30 mg before bed nightly). One injection per week, one capsule daily.
- Maximum injectable output: Tesamorelin 1–2 mg + Ipamorelin 150–300 mcg, once or twice daily. Hits both receptor arms at maximum secretagogue potency. Cost: $10–$36/day.
- Visceral fat as primary goal: Tesamorelin— the only secretagogue with clinical evidence for visceral fat reduction. Dietary discipline required; Tesamorelin amplifies the effect, it doesn’t override a poor diet.
- Above 4 IU equivalent / bodybuilder doses: shift to exogenous HGH. Secretagogues cannot scale past the pituitary rate-limit. Chinese generic HGH is cost-competitive with or cheaper than the Tesamorelin + Ipamorelin stack for equivalent output.
The bottom line
GH secretagogues are amplifiers, not bypasses. Your pituitary function and age set the ceiling. Young users can get real benefit — meaningful GH pulse amplification for recovery, sleep, and body composition. Older users will generally find exogenous HGH more reliable.
For most people starting out, the CJC-1295 + Ipamorelin blend is the right first injectable — dual-receptor coverage, affordable, well-established. Add Sermorelin if sleep quality is a specific goal. Reach for Tesamorelin if visceral fat reduction is the priority. Once you need doses beyond what a secretagogue ceiling allows, the next step is exogenous HGH.
For the reconstitution math on any of these, use the calculators linked above. For the full GH protocol — fasted glucose monitoring, Berberine dosing, cycle structuring — see the free Peptide Guide.