WhatPeptide

Ipamorelin

A selective ghrelin-receptor agonist studied for stimulating GH release with less prolactin/cortisol impact than older GHRPs. Originally placed on FDA Category 2 list (September 2023), then removed September 27, 2024 when the nominator withdrew. FDA still lists it under 'Other bulk drug substances that may present significant safety risks.' Regulatory status remains uncertain.

Moderate evidence FDA Category 2 Growth Hormone Releasing Peptide

Written by WhatPeptide Editorial Team · Last updated 2026-03-17

FDA Category 2 — compounding availability may be limited.

Half-life

Approximately 2 hours

Dosage range

100-300 mcg once to three times daily (published research context)

Administration

Subcutaneous injection

Research level

Moderate

How Ipamorelin works

Ipamorelin binds the growth hormone secretagogue receptor (GHSR-1a) to stimulate pituitary GH release in a pulsatile pattern. Compared with earlier GHRPs, it appears more selective with less ACTH/prolactin spillover in small studies. Real-world body-composition data remains limited.

Also known as: NNC 26-0161, Selective ghrelin mimetic

Research relevance

GH Boost
Strong research relevance 85
Muscle Growth
Moderate relevance 70
Anti-Aging & Longevity
Moderate relevance 65
Sleep & Relaxation
Moderate relevance 65
Recovery & Healing
Moderate relevance 60
Fat Loss
Some relevance 35
Cognition & Focus
Some relevance 30
Hair & Skin
Some relevance 30
Injury Rehab
Some relevance 30
Sexual Health
Some relevance 25
Immune Support
Some relevance 20

Side effects & safety

Headache Water retention Transient numbness Injection-site irritation Elevated IGF-1 — theoretical concern for cancer promotion with prolonged use Possible insulin resistance with chronic use

Contraindications

Pregnancy
Active malignancy concerns
Severe insulin resistance

Consult a healthcare provider before use if any of these apply to you.

Key studies

FAQ

What is Ipamorelin? +
A selective ghrelin-receptor agonist studied for stimulating GH release with less prolactin/cortisol impact than older GHRPs. Originally placed on FDA Category 2 list (September 2023), then removed September 27, 2024 when the nominator withdrew. FDA still lists it under 'Other bulk drug substances that may present significant safety risks.' Regulatory status remains uncertain. Its mechanism of action is supported by moderate clinical and preclinical evidence.
What is Ipamorelin researched for? +
Ipamorelin has the strongest research relevance for GH Boost, Muscle Growth, Anti-Aging & Longevity. Evidence is supported by moderate clinical and preclinical evidence.
What are the side effects of Ipamorelin? +
Reported side effects include Headache, Water retention, Transient numbness, Injection-site irritation, Elevated IGF-1 — theoretical concern for cancer promotion with prolonged use, Possible insulin resistance with chronic use. Key contraindications: Pregnancy; Active malignancy concerns; Severe insulin resistance.
Is Ipamorelin FDA approved? +
Ipamorelin is classified as FDA Category 2, meaning compounding availability may be limited.
How is Ipamorelin administered? +
Ipamorelin is typically administered via subcutaneous route. Researched dosage range: 100-300 mcg once to three times daily (published research context). Half-life: Approximately 2 hours.

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