Ipamorelin vs MK-677 (Ibutamoren)

A detailed comparison to help you understand the differences and choose the right peptide for your research goals.

Ipamorelin

Ipamorelin is a selective growth hormone secretagogue that stimulates the release of growth hormone from the pituitary gland without significantly affecting cortisol or prolactin.

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MK-677 (Ibutamoren)

MK-677, also known as Ibutamoren, is an orally active growth hormone secretagogue. Unlike peptides, it can be taken orally and has a long half-life, providing 24-hour GH elevation.

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Side-by-Side Comparison

Aspect	Ipamorelin	MK-677 (Ibutamoren)
Dose Range	100 mcg–300 mcg	10 mg–25 mg
Frequency	2x daily	1x daily
Cycle Length	8–12 weeks	8–24 weeks
Route	subcutaneous	oral
Mechanism	Acts as a ghrelin mimetic, binding to the ghrelin receptor (GHS-R) in the pituitary to stimulate GH release. Highly selective with minimal effect on other hormones.	Acts as a potent, selective agonist of the ghrelin receptor (GHS-R1a). Increases GH and IGF-1 levels without affecting cortisol. Mimics ghrelin's GH-releasing effects.
Typical Dosage	Typical dosing ranges from 200-300mcg administered 2-3 times daily, often combined with CJC-1295.	Typical dosing: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase.
Administration	Subcutaneous injection. Best results when administered fasted or before sleep. Often stacked with GHRH peptides.	Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing.
Side Effects	Generally well-tolerated. May cause mild headaches, lightheadedness, or increased hunger initially.	Increased appetite and water retention are most common. May cause lethargy, vivid dreams, and mild numbness. Can affect blood glucose and insulin sensitivity.
Best For	Muscle Growth Fat Loss Recovery & Healing Sleep Quality	Muscle Growth Fat Loss Recovery & Healing Sleep Quality