Ipamorelin: Side Effects & Safety

Ipamorelin has one of the most favorable safety profiles among GH secretagogues, owing to its high selectivity for GH release without significant effects on cortisol, prolactin, aldosterone, or appetite. This selectivity was documented in the original 1998 paper by Raun et al., which described ipamorelin as the "first selective growth hormone secretagogue."

Side effects are generally mild, dose-dependent, and related to GH elevation itself rather than off-target effects. The built-in physiological regulation (somatostatin feedback) prevents excessive GH levels, adding an additional safety margin.

For general peptide safety, see Are Peptides Safe?

Side Effect	Frequency	Severity	Notes
Water retention	Common	Mild	Hands, face — a GH-class effect. Resolves with dose reduction
Head rush / dizziness	Common (initial)	Mild	Transient, first few doses. Subsides with continued use
Injection site reactions	Common	Mild	Standard SC effects — redness, irritation
Mild hunger increase	Occasional	Mild	Much less than GHRP-6. Via ghrelin pathway
Numbness / tingling	Occasional	Mild	Extremities — GH-mediated fluid changes
Joint stiffness	Rare	Mild	GH-class effect, usually at higher doses

Importantly, ipamorelin does not significantly increase cortisol, prolactin, or ACTH — distinguishing it from all other GHRPs. This means no cortisol-related anxiety, prolactin-related mood changes, or ACTH-driven hormonal disruption.

Side Effect	Ipamorelin	GHRP-6	GHRP-2	Hexarelin
Cortisol increase	Minimal	Moderate	Moderate	Significant
Prolactin increase	Minimal	Moderate	Moderate	Significant
Hunger increase	Mild	Severe	Moderate	Mild
Water retention	Mild	Moderate	Moderate	Moderate
GH desensitization	Slow	Moderate	Moderate	Rapid

Ipamorelin's selectivity profile is the reason it has become the preferred GHRP in most modern research and clinical protocols. Hexarelin produces the most potent GH release but also the most off-target effects and fastest desensitization. For the GHRH analog side, see sermorelin side effects and CJC-1295 side effects.

Contraindications:

• Active cancer: GH is growth-promoting — all GH-elevating therapies are contraindicated with active malignancy
• Pituitary disorders or acromegaly: Excessive GH production should not be further stimulated
• Diabetic retinopathy: GH elevation may worsen proliferative retinopathy
• Pregnancy and breastfeeding: Not studied in pregnancy

Drug interactions:

• Insulin/oral hypoglycemics: GH has anti-insulin effects — monitor blood glucose in diabetics
• Glucocorticoids: May suppress GH response to ipamorelin
• Food (carbohydrates): Eating within 2 hours before injection suppresses GH release through insulin/somatostatin

Return to the ipamorelin overview for general information. See dosage protocols for fasting requirements.