Ipamorelin — Research, Dosing & Price Guide

Ipamorelin is a selective growth hormone secretagogue pentapeptide that stimulates GH release with remarkable specificity — it activates the ghrelin receptor without significantly affecting cortisol, prolactin, or appetite. This selectivity profile makes it the 'cleanest' GHRP and the most widely used growth hormone peptide for anti-aging, body composition, sleep enhancement, and recovery. Developed by Novo Nordisk in the 1990s, it has become the foundational GH peptide in clinical and self-directed protocols worldwide.

Ipamorelin selectively activates the growth hormone secretagogue receptor type 1a (GHS-R1a) on somatotroph cells in the anterior pituitary gland. Upon receptor binding, it triggers phospholipase C activation, IP3-mediated calcium release from the endoplasmic reticulum, and subsequent GH vesicle exocytosis — producing a pulsatile GH release that closely mimics the body's natural secretion pattern. What distinguishes Ipamorelin from other GHRPs is its extraordinary selectivity. While GHRP-2, GHRP-6, and hexarelin also bind GHS-R1a, they produce dose-dependent increases in ACTH, cortisol, and prolactin due to off-target receptor interactions. Ipamorelin, even at doses 100-fold above the effective GH-releasing dose, produces negligible effects on cortisol and prolactin. This selectivity was demonstrated in pivotal studies by Raun et al. (1998) and makes Ipamorelin uniquely suitable for long-term use. Ipamorelin also has minimal appetite-stimulating effects compared to GHRP-6, as it does not significantly activate the hypothalamic hunger circuits driven by ghrelin receptor agonism in the arcuate nucleus. Its GH release is dose-dependent up to a saturation point of approximately 1 mcg/kg body weight, after which additional doses do not produce proportionally greater GH output. Importantly, Ipamorelin's GH release is still subject to somatostatin-mediated negative feedback — meaning it will not cause supraphysiological GH levels under normal conditions. This physiological 'ceiling' is a key safety feature. When combined with GHRH analogs (such as CJC-1295), a synergistic amplification occurs: GHRH primes the somatotrophs while Ipamorelin triggers release and antagonizes somatostatin, producing GH pulses 3–5 times greater than either peptide alone. This GHRH+GHRP combination is considered the gold standard for GH optimization. Beyond direct GH effects, the elevated GH from Ipamorelin stimulates hepatic IGF-1 production, which mediates many of the downstream anabolic, tissue-repair, and metabolic benefits. Increased GH also enhances lipolysis (fat burning) through hormone-sensitive lipase activation, improves protein synthesis rates, and promotes deep slow-wave sleep — the restorative sleep phase during which GH secretion naturally peaks.

• Raun et al. (1998) published the defining study in the European Journal of Endocrinology demonstrating Ipamorelin's unique selectivity — GH release was dose-dependent while ACTH, cortisol, prolactin, and FSH/LH remained at baseline even at 100x effective doses
• A study in swine models showed Ipamorelin increased bone mineral content by 8% and bone mineral density by 6% over 12 weeks (Bone, 2001)
• Clinical studies in post-surgical patients demonstrated Ipamorelin accelerated bowel function recovery — reduced time to first bowel movement by 12 hours compared to placebo (Annals of Surgery, 2007)
• Research in GH-deficient models showed Ipamorelin restored IGF-1 levels to 70–80% of normal without supraphysiological GH peaks
• Studies demonstrate that Ipamorelin's GH release is still gated by somatostatin negative feedback, providing a built-in physiological safety mechanism not present with exogenous GH
• Comparative GHRP studies show Ipamorelin produces equivalent peak GH levels to GHRP-2 and GHRP-6 at equipotent doses but without the cortisol and prolactin spikes (Hansen et al., 1999)
• Long-term (12-week) administration studies showed sustained GH-releasing efficacy without significant desensitization, unlike hexarelin
• Research in aging models demonstrated Ipamorelin improved sleep architecture — specifically increasing slow-wave (N3) sleep duration, the phase most associated with tissue repair and GH secretion

• Standard anti-aging/wellness dose: 100–300 mcg subcutaneous injection, 1–3 times daily
• Optimal timing: upon waking (fasted), post-workout, and 30 minutes before bed (for maximum GH pulse frequency)
• Saturation dose: ~1 mcg/kg body weight per injection (100 mcg for 100 kg individual)
• GH amplification stack: combine with 100 mcg CJC-1295 (no DAC) at each injection point for synergistic release
• Body composition protocol: 200 mcg twice daily (AM fasted + pre-bed) for 12–16 weeks, then 4 weeks off
• Sleep-focused protocol: 200–300 mcg 30 minutes before bedtime only
• Must inject on an empty stomach — wait at least 2 hours after eating and 30 minutes before eating after injection
• Cycle length: 8–16 weeks on, 4 weeks off (though some clinicians prescribe continuously with periodic blood work)
• For women: same dosing applies — Ipamorelin is not sex-hormone-dependent
• 5-days-on, 2-days-off protocol used by some practitioners to prevent desensitization while maintaining convenience

Known Side Effects

• Mild head rush or transient lightheadedness immediately after injection (especially when fasted) — resolves within 5 minutes
• Injection site reactions: minor redness or itching (common, transient)
• Mild water retention during the first 1–2 weeks, typically subsiding as the body adapts
• Occasional tingling or numbness in fingers/toes (transient paresthesia from GH effects)
• Increased dream vividness and sleep depth — often considered a positive effect
• Rare: mild nausea if injected immediately after eating (timing protocol compliance prevents this)
• No significant appetite stimulation (unlike GHRP-6)
• No meaningful cortisol or prolactin elevation at standard doses

Safety Profile

Ipamorelin has arguably the best safety profile of any growth hormone secretagogue, which is why it has become the default recommendation for GH optimization. Its selectivity for GH release without cortisol, prolactin, or appetite disruption eliminates the most common GHRP side effects. The preservation of somatostatin negative feedback means Ipamorelin cannot drive GH to the dangerous supraphysiological levels possible with exogenous GH injections — providing an inherent safety ceiling. Clinical trials in surgical patients and research subjects have shown no serious adverse events. Long-term safety data extends to 12–16 weeks in published studies, with anecdotal clinical data supporting multi-year intermittent use without significant issues. Standard monitoring includes IGF-1 levels (every 3–6 months), fasting glucose, and HbA1c (GH can mildly antagonize insulin action). Contraindications: active malignancy (GH/IGF-1 may promote tumor growth), uncontrolled diabetes, pituitary tumors, and pregnancy. Those with a strong family history of cancer should discuss IGF-1 optimization carefully with their physician. Overall, Ipamorelin provides the most favorable benefit-to-risk ratio in the GH secretagogue class.

Week 1: Improved sleep quality is typically the first noticeable effect — deeper sleep, more vivid dreams, feeling more refreshed upon waking. This reflects enhanced nocturnal GH pulses during slow-wave sleep. Mild water retention possible. Week 2–3: Sleep benefits consolidate. Recovery from exercise improves noticeably — less soreness, faster return to baseline. Skin begins to appear more hydrated and 'fuller.' Subtle improvements in mood and energy. Weeks 4–6: Body composition changes become measurable — reduced subcutaneous fat, improved muscle tone. Hair and nail growth accelerates. Skin quality continues to improve (fine lines appear softer, complexion brighter). Joint comfort may improve as synovial fluid and cartilage benefit from GH effects. Weeks 7–12: Peak protocol benefits. Measurable fat loss (especially truncal/visceral) and lean mass improvements are evident. IGF-1 blood levels typically elevated 30–60% above baseline. Energy and exercise capacity improved. Skin looks noticeably more youthful. Weeks 12–16: Benefits plateau at maximum. After cycling off, improvements in body composition, skin quality, and sleep partially persist for 4–8 weeks before gradually returning toward baseline. Many users adopt a long-term intermittent strategy: 12 weeks on, 4 weeks off, repeating indefinitely.

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