Last updated: March 13, 2026 · Monthly refresh · Updated as new research publishes
Medical disclaimer: This guide is for educational purposes only and is not medical advice. Most GH peptides discussed here are research compounds not approved by the FDA for general use. Always consult a qualified healthcare provider before starting any medication or peptide protocol. See our full medical disclaimer.
In this guide
How growth hormone peptides work Ipamorelin CJC-1295 Sermorelin Tesamorelin GHRP-2 vs GHRP-6 GH peptide comparison table GH peptides vs HGH GH peptide stacks All GH secretagogue content on this site FAQ
How growth hormone peptides work
Growth hormone secretagogues are peptides that stimulate the pituitary gland to produce and release its own growth hormone. This is the fundamental distinction from exogenous HGH, which bypasses the pituitary entirely and delivers synthetic growth hormone directly into the bloodstream.
Secretagogues work through two main signaling pathways, and understanding these two pathways is the key to understanding every GH peptide on the market.
Pathway 1: GHRH analogs. These mimic growth hormone-releasing hormone, the signal the hypothalamus sends to the pituitary to begin GH production and release. CJC-1295 and sermorelin work this way. They amplify the natural release signal. Think of them as turning up the volume on a message the body is already sending.
Pathway 2: Ghrelin mimetics (GHRPs). These activate the ghrelin receptor (GHS-R1a), a separate pathway that triggers GH release independently of GHRH. Ipamorelin, GHRP-2, and GHRP-6 work this way. They open a second door to GH release that operates independently of the GHRH pathway.
The critical concept is pulsatile release. The body naturally releases GH in pulses throughout the day, with the largest pulse occurring during deep sleep. Secretagogues preserve this pulsatile pattern. Exogenous HGH does not. A flat, constant level of GH in the bloodstream carries a different risk profile than the natural surge-and-recede pattern the body evolved to handle.
This is also why stacking a GHRH analog with a ghrelin mimetic is so effective. Activating both pathways simultaneously produces a GH pulse that is significantly larger than either pathway can generate alone. The two signals are synergistic, not just additive.
Ipamorelin
Ipamorelin is a pentapeptide ghrelin mimetic and the most selective growth hormone releasing peptide available. Selective means it stimulates GH release without significantly affecting cortisol, prolactin, or aldosterone levels. That selectivity is the reason ipamorelin has become the default recommendation for GH peptide therapy in most clinical and anti-aging settings.
GHRP-2 and GHRP-6 also stimulate GH release through the ghrelin receptor, but they activate other hormonal pathways as collateral. GHRP-6 causes significant hunger. GHRP-2 can elevate cortisol. Ipamorelin avoids both. The GH release is clean.
Typical dosing is 200-300mcg administered subcutaneously 2-3 times per day. Most protocols call for injection on an empty stomach (at least 2 hours without food) to avoid blunting the GH response. The most common timing is morning (fasted) and before bed.
Ipamorelin is frequently paired with CJC-1295 (without DAC) for a synergistic effect. This combination activates both the GHRH and ghrelin pathways simultaneously, producing a larger GH pulse than either peptide alone.
For the full compound profile, dosing protocols, and research data, see the ipamorelin compound page.
CJC-1295
CJC-1295 is a synthetic GHRH analog that exists in two distinct forms, and the distinction matters.
CJC-1295 with DAC (Drug Affinity Complex) has an extended half-life of approximately 6-8 days. The DAC modification allows it to bind to albumin in the bloodstream, dramatically slowing clearance. This means a single injection can elevate GH levels for nearly a week. Dosing is typically once or twice weekly at 1-2mg per injection. The trade-off is that the sustained elevation blunts the natural pulsatile GH pattern rather than amplifying individual pulses.
CJC-1295 without DAC (also called Modified GRF 1-29) has a half-life of approximately 30 minutes. It produces a sharp, short-lived GH pulse that mirrors natural physiology more closely. This is the version most commonly used in combination with ipamorelin, dosed 1-3 times daily at 100-300mcg per injection. When clinicians refer to the "CJC/Ipamorelin stack," they almost always mean CJC-1295 without DAC.
The choice between the two forms depends on the goal. CJC-1295 with DAC is more convenient (fewer injections) but produces a less physiological GH elevation pattern. CJC-1295 without DAC requires more frequent dosing but preserves natural pulsatile release.
For the full compound profile: CJC-1295 compound page. For weight loss data on the combination: CJC-1295 + ipamorelin weight loss results.
Sermorelin
Sermorelin is a 29-amino-acid GHRH analog that represents the biologically active fragment of natural GHRH (which is 44 amino acids). It was the first GH secretagogue to receive FDA approval, approved in 1997 for the treatment of growth hormone deficiency in children under the brand name Geref.
The manufacturer voluntarily discontinued Geref in 2008 for commercial reasons, not safety concerns. Sermorelin remains available through compounding pharmacies and is one of the most prescribed GH peptides in anti-aging medicine.
As a GHRH analog, sermorelin works through the same pathway as CJC-1295. The key difference is pharmacokinetics. Sermorelin has a shorter half-life (approximately 10-20 minutes) compared to CJC-1295 without DAC (~30 minutes). This means it produces a shorter GH pulse and is typically dosed at bedtime to coincide with the natural nighttime GH surge.
Typical dosing is 200-300mcg subcutaneously at bedtime. Some protocols add a morning dose. Because of its history of FDA approval and established safety profile, sermorelin is often the first-line choice for physicians new to prescribing GH peptides.
For the full compound profile: sermorelin compound page.
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Tesamorelin
Tesamorelin is a GHRH analog that is currently FDA-approved under the brand name Egrifta for the reduction of excess abdominal fat in HIV-infected patients with lipodystrophy. It is the only GH secretagogue with an active FDA approval for any indication in adults.
The mechanism is the same as sermorelin and CJC-1295 — stimulation of the GHRH receptor on the pituitary. What distinguishes tesamorelin is the clinical data behind it. Multiple Phase 3 trials demonstrated significant reduction in visceral adipose tissue (VAT), the metabolically dangerous fat that accumulates around internal organs. VAT reduction ranged from 15-18% over 26 weeks in the pivotal trials.
Tesamorelin is dosed at 2mg subcutaneously once daily. It is the highest-dose GH secretagogue in clinical use and produces the most robust and consistent GH elevation among the GHRH analogs.
Off-label use for general body composition optimization is growing, particularly in combination with GLP-1 medications. The rationale is that GLP-1 drugs drive overall weight loss while tesamorelin specifically targets visceral fat and preserves lean mass through GH-mediated protein synthesis.
For the full compound profile: tesamorelin compound page. For the weight loss stack: semaglutide + tesamorelin weight loss stack.
GHRP-2 vs GHRP-6
GHRP-2 and GHRP-6 are both hexapeptide ghrelin mimetics that stimulate GH release through the ghrelin receptor. They were among the earliest GH secretagogues studied and remain in use, though ipamorelin has largely replaced both in clinical practice due to its superior selectivity.
GHRP-6 produces a strong GH release but also significantly stimulates appetite through direct ghrelin pathway activation. This makes it popular among bodybuilders looking to increase caloric intake during bulking phases, but counterproductive for anyone trying to lose body fat. GHRP-6 also elevates cortisol and prolactin to a modest degree.
GHRP-2 produces a stronger GH release than GHRP-6 — approximately 2-3x higher peak GH levels in comparative studies. It stimulates appetite less than GHRP-6 but more than ipamorelin. It can elevate cortisol and prolactin at higher doses, though less dramatically than GHRP-6.
Factor GHRP-2 GHRP-6 GH release strength Strongest among GHRPs Strong Hunger stimulation Moderate Significant Cortisol elevation Mild at higher doses Mild to moderate Prolactin elevation Mild at higher doses Mild to moderate Typical dosing 100-300mcg, 2-3x/day 100-300mcg, 2-3x/day
Bottom line: if maximum GH output is the goal regardless of side effects, GHRP-2 is the stronger choice. If appetite stimulation is desired (for weight gain), GHRP-6 is useful. For most people seeking clean GH elevation with minimal side effects, ipamorelin has replaced both.
Compound pages: GHRP-2 | GHRP-6
GH peptide comparison table
All six major GH secretagogues compared side by side. This table covers mechanism, GH release strength, selectivity, side effects, typical dosing, and FDA status.
Peptide Mechanism GH Release Selectivity Key Side Effects Typical Dosing FDA Status Ipamorelin Ghrelin mimetic Moderate Highest Minimal 200-300mcg 2-3x/day Research compound CJC-1295 GHRH analog Moderate-High High Water retention, flushing 100-300mcg daily (no DAC) or 1-2mg weekly (with DAC) Research compound Sermorelin GHRH analog Moderate High Injection site reactions, flushing 200-300mcg at bedtime Previously approved (withdrawn) Tesamorelin GHRH analog Highest (GHRH class) High Joint pain, injection site reactions 2mg once daily FDA-approved (Egrifta) GHRP-2 Ghrelin mimetic Highest (GHRP class) Low Cortisol, prolactin, moderate hunger 100-300mcg 2-3x/day Research compound GHRP-6 Ghrelin mimetic High Low Significant hunger, cortisol, prolactin 100-300mcg 2-3x/day Research compound
Structured comparison database pages:
Ipamorelin vs CJC-1295 Tesamorelin vs Ipamorelin Ipamorelin + CJC-1295 vs MK-677
GH peptides vs HGH
The question comes up constantly: why use peptides when you could just inject HGH directly? The answer involves biology, risk, and cost.
Factor GH Peptides Exogenous HGH Mechanism Stimulates natural GH production Injects synthetic GH directly Release pattern Pulsatile (natural) Flat/supraphysiological Pituitary suppression Minimal to none Can suppress natural GH production Side effect risk Lower (dose-limited by pituitary capacity) Higher (acromegaly risk, insulin resistance, edema) Cost $100-$400/month (compounding pharmacy) $1,000-$3,000+/month (pharmaceutical grade) GH ceiling Limited by pituitary output capacity No natural ceiling (dose-dependent)
Pulsatile vs constant release. The body releases GH in pulses. The largest pulse happens during deep sleep. Smaller pulses occur throughout the day, often triggered by exercise or fasting. Secretagogues amplify these natural pulses. Exogenous HGH creates a sustained, non-physiological elevation that the body did not evolve to handle continuously. Long-term supraphysiological GH levels increase the risk of insulin resistance, joint issues, and potentially abnormal tissue growth.
Pituitary suppression. When you inject exogenous GH, the pituitary receives feedback that GH levels are already elevated and reduces its own production. Over time, this can lead to dependence on exogenous GH. Secretagogues work with the pituitary, not instead of it. The feedback loop remains intact.
The cost gap. Pharmaceutical-grade HGH (brands like Norditropin, Genotropin, Humatrope) runs $1,000-$3,000+ per month depending on dose. GH peptides from compounding pharmacies typically run $100-$400 per month. This is not a marginal difference.
When HGH still makes sense. For diagnosed GH deficiency confirmed by stimulation testing, exogenous HGH replacement under endocrinologist supervision is the standard of care. For bodybuilders seeking supraphysiological GH levels beyond what the pituitary can produce, exogenous HGH is the only option. For everyone else — age-related GH decline, body composition optimization, recovery enhancement — peptides offer a more physiological approach with a better risk-to-benefit ratio.
GH peptide stacks
CJC-1295 + Ipamorelin (the classic stack)
This is the most widely prescribed GH peptide combination. CJC-1295 without DAC (GHRH analog) amplifies the GH release signal while ipamorelin (ghrelin mimetic) triggers release through a separate pathway. The result is a GH pulse significantly larger than either peptide produces alone. Typical protocol is 100-300mcg of each, injected together subcutaneously 1-3 times daily.
Detailed stack profile: CJC-1295 + ipamorelin GH optimization stack.
GH peptides + BPC-157 (recovery stack)
BPC-157 is a healing peptide with strong angiogenic and anti-inflammatory properties. Combining it with a GH peptide stack addresses recovery from two angles: GH drives protein synthesis and tissue repair at the systemic level, while BPC-157 accelerates local healing at the injury site. This combination is popular among athletes and people recovering from injuries or surgery.
GH peptides + GLP-1 medications (body composition stack)
An emerging protocol combines GH peptides (typically tesamorelin or ipamorelin/CJC-1295) with GLP-1 receptor agonists like semaglutide. The rationale: GLP-1 drugs drive significant weight loss but do not distinguish between fat and lean mass. GH peptides promote lean mass preservation and preferentially target visceral fat. The combination aims for better body composition outcomes than either approach alone.
All GH-related stacks:
GH Optimization Stack (general) CJC-1295 + Ipamorelin GH Stack Muscle Growth Stack: CJC-1295 + Ipamorelin + IGF-1 Weight Loss Stack: Semaglutide + Tesamorelin
Medical disclaimer: The information on this page is for educational and informational purposes only. It is not intended as medical advice, diagnosis, or treatment. Most GH peptides discussed here are research compounds not approved by the FDA for general use. Always consult a qualified healthcare provider before starting any medication or peptide protocol. Individual results vary. See our full medical disclaimer.