Ipamorelin Dosing: Selective GHRP Protocol (2026)

Ipamorelin is a selective growth hormone releasing peptide (GHRP) that stimulates natural growth hormone production through the ghrelin receptor. It's considered the most selective GHRP available, earning the nickname "the cleanest GHRP" for its minimal effects on cortisol and prolactin.

Clinical development was discontinued despite positive Phase II results. Community protocols are based on clinical trial dosing and extrapolation. This is not medical advice.

Quick Reference: Community Dosing

If you're here for the practical protocol, here it is:

Most people start with 300 mcg once daily (morning or evening) and may progress to twice daily based on goals and response. Always take on an empty stomach for optimal GH response.

For the full Ipamorelin peptide profile, vendor pricing, and stack protocols, see our Ipamorelin peptide page.

Loading vs Maintenance

Ipamorelin doesn't use traditional loading phases, but there are progression patterns:

Weeks 1–2 (Assessment): Start with 300 mcg once daily to assess tolerance and response. Monitor for any side effects and establish baseline energy/recovery.

Weeks 3–8 (Maintenance): Continue once daily or progress to twice daily (morning and evening) for enhanced growth hormone pulsatility.

The 5 on/2 off pattern: Take for 5 consecutive days, then 2 days off each week. This prevents receptor desensitization and maintains sensitivity to Ipamorelin's GH-releasing effects.

Timing Optimization

• Single daily dose: Either first thing in the morning (fasted) or before bed (3+ hours post-dinner)
• Twice daily: Morning fasted + evening 3+ hours after last meal
• Never with food: GH response is significantly blunted when taken with meals

Routes of Administration

Subcutaneous Injection (Only Practical Route)

Ipamorelin is administered exclusively via subcutaneous injection:

• Injection sites: Abdomen, love handles, thighs — anywhere with subcutaneous fat
• Volume: Typically 0.12 mL (12 units on insulin syringe) for 300 mcg dose
• Needle: 29–31 gauge insulin syringe

Why not oral? Like most GHRPs, Ipamorelin is degraded by stomach acid and has poor oral bioavailability.

Why not nasal? While theoretically possible, subcutaneous provides consistent dosing and was the route used in clinical trials.

Where These Numbers Come From: Clinical Context

Community Ipamorelin protocols are directly informed by clinical trial data, making the dosing rationale more evidence-based than many peptides.

Phase II Clinical Trial

The primary clinical evidence comes from a Phase II trial for postoperative ileus:

• Study design: Placebo-controlled trial in patients undergoing bowel surgery
• Dosing: 0.01–0.1 mg/kg IV (roughly 1–7 mg for a 70 kg person)
• Results: Significant reduction in time to bowel function recovery
• Safety: Excellent tolerability with minimal side effects (Barlind et al., 2008)

Growth Hormone Studies

Earlier research established Ipamorelin's GH-releasing profile:

• Dose-response studies — Showed significant GH release starting at low doses
• Selectivity profile — Minimal cortisol/prolactin elevation compared to other GHRPs (Raun et al., 1998)
• Duration of action — GH elevation peaks at 30–60 minutes, returns to baseline within 3–4 hours

Community Protocol Development

The standard 300 mcg dose comes from:

1. Scaling down from clinical doses — Clinical IV doses (1–7 mg) are much higher than needed for GH release
2. Optimal GH response curve — 300 mcg provides meaningful GH pulses without side effect escalation
3. Selectivity advantage — Ipamorelin's high selectivity allows effective dosing at lower amounts than other GHRPs

Why Community Doses Are Conservative

Clinical trials used higher doses (1–7 mg IV) than community protocols (300 mcg SC) because:

• Different endpoints — Clinical trials targeted gastric motility; community use targets GH release
• Route differences — IV has higher bioavailability than SC, allowing lower SC doses
• Selectivity benefit — Ipamorelin's specificity means lower doses still provide meaningful GH elevation
• Side effect avoidance — Conservative dosing minimizes any potential unwanted effects

Mechanism of Action

Ipamorelin works through highly selective ghrelin receptor activation, which sets it apart from other GHRPs:

Ghrelin receptor (GHSR-1a) binding — Ipamorelin binds specifically to the ghrelin receptor in the hypothalamus and pituitary, triggering natural growth hormone release (Raun et al., 1998).

Selective GH release — Unlike GHRP-2, GHRP-6, and Hexarelin, Ipamorelin doesn't significantly elevate cortisol, prolactin, or ACTH. This selectivity is its primary advantage (Johansen et al., 1999).

Natural pulsatile pattern — Mimics natural GH release patterns rather than creating sustained elevation, preserving the body's normal GH rhythms.

IGF-1 mediated effects — GH elevation leads to increased IGF-1 production in the liver, which mediates many of the downstream anabolic and recovery effects.

No desensitization to natural GHRH — Unlike some GHRPs, Ipamorelin doesn't interfere with the body's natural growth hormone releasing hormone (GHRH) sensitivity.

Side Effects & Safety

Ipamorelin has one of the cleanest safety profiles among GHRPs, which is why it's often called the most selective option.

Clinical Trial Safety Data

Phase II trials showed excellent tolerability:

• No serious adverse events attributed to Ipamorelin
• No significant changes in blood pressure, heart rate, or laboratory values
• No hormonal disruption — cortisol, prolactin, and ACTH remained stable
• Well-tolerated across all dose ranges tested (Barlind et al., 2008)

Community-Reported Side Effects

Side effects are minimal and typically mild:

Most common:

• Injection site redness or irritation
• Mild water retention
• Increased appetite (from GH elevation)

Uncommon:

• Mild headache
• Temporary fatigue (usually in first week)
• Numbness or tingling (very rare)

What Makes Ipamorelin "Cleaner"

Compared to other GHRPs, Ipamorelin avoids several side effects:

• No cortisol elevation — Unlike GHRP-2/GHRP-6 which can raise cortisol
• No prolactin increase — Hexarelin can significantly elevate prolactin; Ipamorelin doesn't
• No hunger spikes — GHRP-6 causes intense hunger; Ipamorelin may slightly increase appetite but not dramatically
• No water retention — Less tendency for bloating compared to other growth hormone stimulators

Contraindications

• Active cancer — GH elevation could theoretically promote tumor growth
• Severe diabetes — GH can affect glucose metabolism
• Pregnancy/nursing — No safety data available

Stacking Ipamorelin

Ipamorelin is frequently combined with other peptides for enhanced effects or comprehensive protocols:

Ipamorelin + CJC-1295 (Most Popular Stack)

The gold standard GHRH/GHRP combination:

• Ipamorelin → triggers GH release (GHRP function)
• CJC-1295 → amplifies and extends GH release (GHRH analog)

Synergy: GHRH analogs (CJC-1295) and GHRPs (Ipamorelin) work through different but complementary pathways, creating higher and more sustained GH elevation.

Ipamorelin + Sermorelin

All-natural GH stimulation stack:

• Ipamorelin → selective GHRP
• Sermorelin → natural GHRH analog

Both are considered more "physiological" than synthetic alternatives.

Ipamorelin + Other GHRPs (Advanced)

Some experienced users rotate between GHRPs to prevent desensitization:

• Weeks 1–4: Ipamorelin 300 mcg
• Weeks 5–8: GHRP-2 100 mcg or GHRP-6 100 mcg

Rationale: Different GHRPs may prevent receptor downregulation, though this is theoretical.

Stacking Guidelines

• Same injection site: Ipamorelin and CJC-1295 can be mixed in the same syringe
• Timing is critical: Always maintain fasted state for optimal GH response
• Start separately: Assess individual response before combining peptides

Frequently Asked Questions

What is the standard Ipamorelin dose?

The most common protocol is 300 mcg per injection (12 units on insulin syringe), taken 1–2 times daily on an empty stomach, with 5 days on/2 days off, cycled 8 weeks on/off.

Why is Ipamorelin considered the 'cleanest' GHRP?

Ipamorelin has the highest selectivity for growth hormone release with minimal cortisol and prolactin elevation. This selectivity provides clean GH pulses without the hormonal side effects seen with GHRP-2, GHRP-6, or Hexarelin.

Should I take Ipamorelin once or twice daily?

Both work. Once daily (AM or PM) is simpler and cost-effective. Twice daily provides more consistent GH elevation but doubles cost and injection frequency. Start with once daily and assess response.

How long should an Ipamorelin cycle last?

Most protocols run 8 weeks on, 8 weeks off, with 5 days on/2 days off each week. This cycling prevents receptor desensitization while allowing consistent progress.

Can Ipamorelin be taken with food?

No — always take on an empty stomach. Food, especially carbohydrates and fats, significantly blunts the GH response. Wait 2+ hours after eating or take first thing in the morning fasted.

Is Ipamorelin FDA-approved?

No. Ipamorelin completed Phase II trials for postoperative ileus with positive results but never received FDA approval. Development was discontinued for commercial reasons, not safety concerns.

How do I reconstitute Ipamorelin?

Add 2 mL bacteriostatic water to a 5 mg vial (2,500 mcg/mL). 300 mcg = 12 units on insulin syringe. Swirl gently, refrigerate, use within 28 days.

What are the side effects of Ipamorelin?

Minimal side effects due to its selectivity. Occasional injection site redness, mild water retention, or increased appetite. Unlike other GHRPs, it doesn't typically elevate cortisol or prolactin.

Related Guides

• Ipamorelin Peptide Page — Vendor pricing, stack protocols, and full peptide profile
• CJC-1295 + Ipamorelin Stack Guide — Complete combination protocol
• GHRP-2 Dosing Guide — Alternative GHRP for comparison
• Sermorelin Dosing Guide — Natural GHRH analog alternative

References

For educational and research purposes only. This is not medical advice. Ipamorelin has clinical trial safety data but is not FDA-approved for any indication.