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Ipamorelin5 residues (approx.)HFFKEach bubble = one amino acid. Size = residue mass. Color = chemical class.Uses closest standard amino acids for non-standard residues.Also known as: NNC 26-0161, Ipamorelin
Raun and colleagues tested ipamorelin at 200 times the effective growth hormone dose and still found zero cortisol or ACTH elevation [1]. That result made it the first selective growth hormone secretagogue, a pentapeptide that triggers a clean GH pulse through the ghrelin receptor (GHS-R1a) without touching appetite, prolactin, or stress hormones. No human efficacy trial has succeeded yet; the single Phase 2b RCT missed its endpoint. Still, hundreds of r/peptides threads and a 4.5/5 community sentiment score put ipamorelin in the top five most-discussed peptides. Adults looking for GH optimization with the fewest hormonal side effects start here, usually stacked with CJC-1295 (no DAC).
Zero cortisol increase at 200 times the effective GH dose. That single data point from Raun et al. (1998)[1] explains why ipamorelin became the default starter peptide for growth hormone optimization. Ipamorelin (molecular weight ~711 Da) is a synthetic pentapeptide and selective GHS-R1a agonist. It binds the ghrelin receptor on pituitary somatotroph cells, producing a GH pulse within 15 to 30 minutes of subcutaneous injection. Human pharmacokinetic modeling by Svensson et al. (1999)[2] confirmed a 2-hour half-life, roughly 95% subcutaneous bioavailability, and a dose-response ceiling around 300 to 400 mcg per injection. Going higher doesn't produce a bigger pulse. The real-world use case is straightforward. Most users inject 100 to 300 mcg subcutaneously, one to three times daily on an empty stomach. Nearly everyone stacks it with CJC-1295 (no DAC), also called Mod GRF 1-29, to hit both GHS-R1a and GHRH receptor pathways simultaneously. That dual-pathway approach produces a synergistic GH pulse two to three times larger than either peptide alone. Bedtime dosing is the priority; the fasting window matters because insulin raises somatostatin, which fully blunts the GH response. Community evidence is strong. Hundreds of r/peptides threads (roughly 95,000 subscribers) consistently report improved sleep within one to two weeks, faster recovery by weeks three to four, and gradual body composition changes over six to twelve weeks. The scientific picture is less complete. The only finished human RCT (Phase 2b for postoperative ileus) failed its primary endpoint versus placebo. All efficacy data for anti-aging and body composition applications is community-derived. Preclinical work on bone mineral content (Andersen et al. 1999)[3] and cachexia (2024 ferret model)[4] looks promising but hasn't been replicated in humans.
Ipamorelin binds selectively to the growth hormone secretagogue receptor type 1a (GHS-R1a) on anterior pituitary somatotroph cells. This receptor is the same target ghrelin activates, but ipamorelin was engineered to hit GH release pathways without meaningfully engaging the feeding behavior pathway that makes GHRP-6 cause intense hunger. Once GHS-R1a activates, it triggers intracellular calcium signaling in somatotrophs, prompting GH vesicle release into circulation. The resulting GH pulse peaks within 15 to 30 minutes of subcutaneous injection per human PK-PD data (Svensson et al. 1999)[2]. That pulse then stimulates hepatic IGF-1 production, the downstream mediator of most growth hormone effects on tissue repair, lipolysis, and protein synthesis. The selectivity is what sets ipamorelin apart. GHRP-2 and GHRP-6 both activate GHS-R1a but also stimulate ACTH release, cortisol secretion, and prolactin elevation at therapeutic doses. Raun et al. (1998)[1] demonstrated that ipamorelin produced no measurable cortisol or ACTH increase even at doses 200 times above the GH-effective threshold. This means it can be dosed multiple times daily without accumulating stress hormone burden. The 2-hour half-life [2] allows for a pulsatile dosing pattern that mimics natural GH secretion rhythms rather than creating the sustained tonic GH elevation seen with CJC-1295 (with DAC). Pairing ipamorelin with CJC-1295 (no DAC) hits both the GHS-R1a and GHRH receptor simultaneously, producing a complementary pulse roughly two to three times larger than either alone.
Mechanism well-established: selective GHS-R1a agonist producing a clean GH pulse without cortisol, ACTH, prolactin, or appetite co-activation (Raun et al. 1998)[1]. Human PK-PD confirmed SC half-life ~2h, SC bioavailability ~95%, dose ceiling at ~300–400 mcg/injection (Svensson et al. 1999)[2]. The only completed human RCT (Phase 2b, postoperative ileus; PMID ~25331030: verify) showed no efficacy vs. placebo. Ipamorelin has never passed a positive human efficacy trial. No new human RCTs published 2024–2026; new 2024 animal data [4] supports cachexia application but is preclinical only.
Raun et al. 1998 (PMID 9849822): established ipamorelin as first selective GHS; no cortisol/ACTH elevation even at 200× the effective GH dose. Svensson et al. 1999 (PMID 10496658): human PK-PD modeling confirming 2h half-life, ~95% SC bioavailability, and dose-response ceiling.
Only completed human RCT (Phase 2b, postoperative ileus) failed primary endpoint: no approved clinical indication. All long-term dosing and efficacy data is community-derived. Preclinical findings (bone, fat) not replicated in a human trial. New 2024 cachexia study (PMID 39043357) is ferret model only.
Widely regarded as the safest and most beginner-friendly GHRP. "Cleanest GHRP": no cortisol, prolactin, or appetite spike vs. GHRP-2 and GHRP-6. Almost universally stacked with CJC-1295 (no DAC) rather than used solo. Primary uses: GH optimization, sleep quality, body recomposition, recovery.
Science and community agree on GHS-R1a mechanism, selectivity vs. other GHRPs, GH pulse characteristics, and 2h half-life. Community dosing of 100–300 mcg/injection aligns with published PK-PD dose-response data. Key divergence: the only human RCT (postoperative ileus, Phase 2b) failed vs. placebo, while community consistently reports sleep and body composition benefits from off-label use. Community applications differ from the failed clinical indication. Fasting window requirement is mechanistically sound (insulin→somatostatin→blunted GH pulse).
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 100mcg | Daily |
| Moderate | 200mcg | 2x Daily |
| Aggressive | 300mcg | 3x Daily |
With a 2 mg vial and 2 mL bacteriostatic water, you'll get 1,000 mcg/mL. Each 100 mcg dose is 10 units on an insulin syringe. A 5 mg vial reconstituted with 2 mL gives 2,500 mcg/mL, so 200 mcg is 8 units and 300 mcg is 12 units per injection. The fasting window is the thing most beginners mess up. You need at least two hours with no food before injection. Insulin triggers somatostatin release, which completely blocks the GH pulse. Eating within that window isn't "suboptimal"; it negates the injection entirely. No food for 30 minutes after, either. Bedtime dosing is priority number one. It amplifies the natural nocturnal GH pulse. If you're dosing twice daily, the morning shot should be fasted on waking. Space injections at least eight hours apart. Store lyophilized vials at 2 to 8 degrees Celsius. After reconstitution, keep refrigerated and use within three to four weeks. Toss anything cloudy or with particles floating in it. If you see zero sleep improvement after two weeks with correct fasting timing, suspect the product before blaming the protocol. Get an IGF-1 lab at week four to confirm the peptide is actually working. Vendor quality varies significantly.
Cycle to maintain receptor sensitivity. Can also be run 5 days on, 2 off weekly.
Ipamorelin has notably lower desensitization risk than other GHRPs (especially hexarelin) due to GHS-R1a selectivity and absence of ACTH pathway activation. The 12-week on/4-week off cycle is precautionary, not evidence-based specifically for ipamorelin. No published RCT-level data on ipamorelin-specific desensitization or tachyphylaxis in humans. Community experience and analog literature support cycling to maintain pituitary somatotroph sensitivity and natural GH axis rhythm. Some longevity clinics run 5 days on/2 days off weekly cycling as an alternative within longer-duration protocols. Extended continuous use (>16 weeks) has produced community-reported diminishing returns, particularly in sleep improvement.
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Expected: Improved sleep quality weeks 1–2; recovery improvement weeks 3–4; modest body composition changes by months 2–3
Monitor: Baseline IGF-1 before starting; recheck at week 6 and week 12. Fasting glucose at baseline.
I have personally seen the best results using Ipamorelin before bedtime on an empty stomach.
Pull bacteriostatic water into an insulin syringe (29 to 31 gauge). For a 2 mg vial, add 2 mL BAC water to get 1,000 mcg per mL. For a 5 mg vial, add 2 mL to get 2,500 mcg per mL. Let the water slide down the glass wall of the vial. Never spray directly onto the lyophilized powder. Swirl gently until dissolved.
At 1,000 mcg/mL (2 mg vial + 2 mL): 100 mcg = 10 units, 200 mcg = 20 units, 300 mcg = 30 units. At 2,500 mcg/mL (5 mg vial + 2 mL): 100 mcg = 4 units, 200 mcg = 8 units, 300 mcg = 12 units.
At least two hours since your last meal. No exceptions, the GH pulse is fully blunted by insulin.
Abdomen (avoiding the navel area) is preferred. Rotate sites with each injection.
Pinch the skin, insert the needle at a 45-degree angle, inject slowly, and hold for five seconds before withdrawing.
If stacking with CJC-1295 (no DAC), draw both peptides into the same syringe or inject at the same site sequentially. Co-administration at the same time is standard.
Store the reconstituted vial in the refrigerator immediately.
Timing: bedtime is the priority injection (30 to 60 minutes before sleep). If dosing twice daily, add an AM fasted injection on waking. If three times daily, add a post-workout fasted injection spaced at least three hours from other doses.
Bioavailability ~20% intranasal vs. ~95% SC (Johansen et al. ~1998, PMID 9879640: verify journal). Would require ~5× higher dose to match SC exposure.
Not used in practice due to low and variable mucosal absorption. No standardized intranasal protocol exists in community or clinical settings. SC injection remains the only practical route.
Primary and near-universal stack. GHRP (GHS-R1a via ipamorelin) + GHRH (GHRHR via CJC-1295 no-DAC) activates dual pituitary pathways for synergistic GH pulse 2–3× greater than either alone. Co-injected at same site, same time. The no-DAC form (not with DAC) preserves pulsatile GH release matching ipamorelin's mechanism.
100 mcg CJC-1295 (no DAC) + 200 mcg ipamorelin SC co-injected, 1–2× daily, fasted
Pre-mixed 5mg/5mg blend: same mechanism as separate components combined for convenience. Common in telehealth/clinic prescriptions and some research vendors.
200–300 mcg total blend SC, 1–2× daily, fasted
Injury recovery stack. GH elevation from ipamorelin complements BPC-157's tissue repair signaling for tendon, ligament, and muscle recovery. Different mechanism: separate injections acceptable (BPC-157 near injury site; ipamorelin systemic SC).
Systemic healing and anti-inflammatory effects combined with GH secretagogue anabolic signaling. Used in injury or post-surgery recovery protocols; both administered SC.
Concurrent use of two GHRPs causes receptor competition at GHS-R1a with no additional GH benefit. GHRP-6's intense hunger and ghrelin-pathway activation defeats the primary reason to choose ipamorelin (clean, appetite-free profile). Stack one GHRP only.
Competing GHRPs at the same GHS-R1a receptor: no additive GH benefit documented. GHRP-2 adds cortisol and prolactin co-elevation that ipamorelin specifically avoids. Defeats the rationale for choosing ipamorelin. Choose one GHRP per stack.
DAC version's days-long half-life creates sustained tonic GH stimulation that mismatches ipamorelin's pulsatile mechanism. Suppresses natural nocturnal GH peaks and pituitary pulsatility over time. Use CJC-1295 no-DAC (Mod GRF 1-29) instead.
Combining GH secretagogues with exogenous HGH saturates the GH axis, suppresses endogenous pulsatility, and eliminates the primary rationale for secretagogue use (axis preservation). Dramatically increases IGF-1 overshoot and side-effect risk.
Do not combinePricing updated 2026-04-09
The most serious risk with ipamorelin is IGF-1 overshoot. Sustained supraphysiological IGF-1 levels carry a theoretical cancer promotion risk, particularly in anyone with active malignancy or a history of cancer. GH promotes cell proliferation. That's the mechanism behind its benefits and its biggest concern. If IGF-1 climbs above the age-adjusted upper normal range on two consecutive readings, the protocol should stop. Carpal tunnel symptoms (tingling or numbness in the hands) are the clearest signal that GH levels have gone too high. Community reports flag this primarily at the aggressive tier (300 mcg three times daily). This isn't a "push through it" side effect. Tingling means stop immediately, wait at least four weeks, and restart at a lower dose and frequency if appropriate. Water retention is common, especially at twice-daily or three-times-daily dosing. Mild puffiness around the face or ankles is the typical presentation. Reducing injection frequency (not dose) is the first adjustment. Transient headache within 30 to 60 minutes of injection is expected and relates directly to the acute GH pulse. It resolves within hours for most users. Cutting the dose by 25% usually handles persistent headache. Injection-site reactions (mild redness, irritation) are reported frequently in the first two weeks and tend to resolve with consistent site rotation. Abdomen is the preferred injection location. Occasional lightheadedness immediately post-injection is reported but typically mild. Published side effect data in humans is limited. The only completed human RCT (Phase 2b, postoperative ileus, approximately 100 participants) recorded adverse events but focused on GI recovery endpoints rather than the subcutaneous anti-aging use case. Community side-effect reporting across hundreds of threads is remarkably consistent, which provides reasonable confidence in the profile above, but formal incidence rates don't exist for the off-label application. GH release antagonizes insulin action. Fasting glucose should be monitored at baseline, week six, and week twelve. Anyone with uncontrolled diabetes or severe insulin resistance should not use ipamorelin. A fasting glucose above 126 mg/dL means discontinuation. Pregnancy and breastfeeding are contraindicated due to insufficient safety data. GH supplementation can also unmask subclinical hypothyroidism by accelerating T4-to-T3 conversion; thyroid monitoring (TSH, fT3) is recommended at baseline. When to see a doctor: persistent hand tingling or numbness, significant edema, fasting glucose above 126 mg/dL, any visual changes, or symptoms of intracranial hypertension.
Verify Ipamorelin dosing and safety with a second opinion
No GMP requirement applies to "research use only" vendors. Ipamorelin (MW ~711 Da) is a smaller, simpler peptide than CJC-1295 (~3.4 kDa), making synthesis somewhat more consistent, but quality variance across vendors remains significant. Key risks: (1) underdosing: peptide content lower than labeled, reducing efficacy; (2) DAC/no-DAC mislabeling is less of an issue for pure ipamorelin than for CJC blends, but still documented; (3) degradation from improper storage or reconstitution. Peptide Sciences, previously a major US vendor, shut down March 2026 following FDA enforcement pressure, disrupting the market. Independent vendor testing (Finnrick Analytics) shows purity ranges from ~70% to 99.95% across GHRP vendors. Athletes: ipamorelin is on WADA 2026 Prohibited List (S2.4: GH Releasing Factors); contamination risk from non-dedicated facilities.
| Test | When | Target |
|---|---|---|
| IGF-1 | Baseline before starting; repeat at week 6 and week 12 | Age-adjusted normal range (not supraphysiological). Flag if consistently above upper limit of normal. |
| IGFBP-3 | Baseline; repeat at week 12 | Age-adjusted normal range |
| Fasting glucose | Baseline; repeat at week 6 and week 12 | <100 mg/dL (normal); 100–125 mg/dL warrants dose reduction and closer monitoring; >126 mg/dL = discontinue |
| Thyroid (TSH, fT3) | Baseline; repeat at week 12 if symptoms emerge | — |
Primary efficacy marker for GH axis activation. Confirms peptide is working and dosing is adequate. Elevated IGF-1 above age-adjusted upper normal indicates dose reduction needed.
Low IGFBP-3 with elevated IGF-1 increases free (bioactive) IGF-1 fraction and downstream cancer signaling risk. IGF-1 alone is insufficient for safe GH axis monitoring.
GH release antagonizes insulin action. Relevant for pre-diabetic or insulin-resistant individuals. Risk is lower than with exogenous HGH but warrants monitoring at higher doses.
GH accelerates T4-to-T3 conversion. Untreated hypothyroidism blunts GH response to ipamorelin. GH supplementation can unmask subclinical hypothyroidism.
Improved sleep quality and deeper sleep onset. Mild injection-site reactions may occur. GH pulses begin but effects are not yet visible.
Noticeable improvements in recovery after exercise. Subtle skin and energy changes. GH and IGF-1 levels begin to rise measurably.
Fat loss becomes apparent, especially around the midsection. Recovery time shortens. Joint and soft-tissue comfort may improve.
Peak benefits in body composition, sleep quality, and recovery. Skin elasticity and tone improvements reported. IGF-1 levels stabilize at elevated baseline.
Receptor sensitivity reset period. Retain most gains from the cycle. GH and IGF-1 gradually return toward pre-cycle baseline over 2-4 weeks.
Weeks 1 to 2: GH pulse augmentation starts with the first injection. Svensson's PK-PD data [2] confirms a GH spike within 15 to 30 minutes of subcutaneous dosing. Sleep quality is the first thing most users notice, often within the first week or two. Deeper sleep onset and more vivid dreams show up consistently across community reports. Mild injection-site redness is common and resolves within hours. Some users report lightheadedness right after the shot. Transient headache in the first 30 to 60 minutes is expected from the acute GH release. Weeks 3 to 4: IGF-1 becomes measurably raised around week four. Recovery after training improves noticeably, with reduced DOMS and faster bounce-back between sessions. Subtle skin texture and hydration changes start showing up. Some users spot early lean tissue fullness and a bump in daily energy. Mild water retention is possible at twice-daily dosing frequency. Weeks 5 to 8: Fat loss becomes visible, particularly around the midsection. Recovery windows keep shrinking. Joint and soft-tissue comfort improvements get mentioned frequently in this phase. Skin elasticity changes are noticeable for some users. Rodent studies at this duration showed bone mineral content improvements (Andersen et al. 1999)[3], though human data for this endpoint doesn't exist yet. Weeks 9 to 12: Peak cycle window. Body composition results are at their best here, with fat loss and muscle fullness peaking. Sleep quality holds steady. Some users report diminishing returns around weeks 10 to 12 and choose to end the cycle early. At the aggressive tier (300 mcg three times daily), mild carpal tunnel-like symptoms are possible. Water retention is the most common nuisance at this stage. Weeks 13 to 16 (off-cycle): Ipamorelin's short half-life (roughly 2 hours) means it clears the system within 10 to 12 hours of the last injection, no prolonged GH bleed. Pituitary GHS-R1a receptor sensitivity recovers within two to four weeks off. Most users retain a solid portion of their cycle gains for four to six weeks post-cycle. GH and IGF-1 drift back toward pre-cycle baseline gradually. No crash or acute withdrawal has been reported.
GH pulse augmentation begins with first injection. Human PK-PD (Svensson 1999) confirms GH spike within 15–30 min of SC injection. IGF-1 elevation detectable within days of consistent dosing.
Improved deep sleep quality and more vivid dreams are the first-reported effects, often within 1–2 weeks. Mild injection-site redness resolving within hours. Occasional lightheadedness immediately post-injection.
IGF-1 measurably elevated at week 4 (consistent with GH axis studies). GH promotes anabolic signaling in connective tissue and muscle protein synthesis.
Faster workout recovery, reduced DOMS, subtle improvements in skin texture and hydration. Some users notice early lean tissue fullness and improved energy.
Sustained GH/IGF-1 elevation drives lipolysis and anabolic signaling. Bone mineral content improvements shown at 12+ weeks in rodent models (Andersen et al. 2000, PMID 10828840).
Fat loss begins to show, particularly midsection. Recovery time shortens noticeably. Joint and soft-tissue comfort improvements reported. Skin elasticity improvements noted by some users.
GH and IGF-1 plateau at sustained elevated baseline. Bone mineral content progressively improves with continued dosing per rodent data. No desensitization documented in ipamorelin-specific literature.
Best body composition results of the cycle: fat loss and muscle fullness peak. Sleep quality sustained. Some users experience diminishing returns by weeks 10–12 and end cycle early.
Short half-life (~2h) means ipamorelin clears within 10–12h of last injection (no prolonged GH bleed). Pituitary GHS-R1a receptor sensitivity should recover within 2–4 weeks off.
Most users retain a significant portion of cycle gains for 4–6 weeks post-cycle. GH and IGF-1 gradually return toward pre-cycle baseline over 2–4 weeks. No crash or acute withdrawal reported.
Source: PK-PD modeling in human volunteers (Pharm Res 1999, PMID 10496658)
Loading the interactive decay curve.
Ipamorelin is classified as "research use only" in the United States. It has no FDA approval for any clinical indication. The single completed human RCT (Phase 2b, postoperative ileus) did not lead to an approved application. US 503A compounding pharmacies cannot legally compound ipamorelin following the FDA PCAC vote against 503A listing in December 2024. RFK Jr. announced on February 27, 2026, that approximately 14 Category 2 peptides (including ipamorelin) would be reclassified to allow compounding, but no formal Federal Register rule has been published. Legal compounding remains suspended. Telehealth and anti-aging clinics offering ipamorelin (typically as a CJC/Ipa combo) do so under physician oversight with pricing around $200 to $600 per month including labs and prescription. Research-grade ipamorelin is available from peptide vendors at approximately $30 to $65 per 5 mg vial. Peptide Sciences, previously a major US vendor, shut down in March 2026 following FDA enforcement pressure. Athletes: ipamorelin is on the WADA 2026 Prohibited List under S2.4 (Growth Hormone Releasing Factors). It is detectable via urine immunoassay. Any athlete subject to anti-doping testing should not use this compound. This content is for educational and research purposes only. Nothing here constitutes medical advice. Consult a licensed healthcare provider before using any peptide.
Peptide Schedule Research TeamReviewed Apr 20266 Citations
