MK-677 (Ibutamoren) Dosage Guide

MK-677 (Ibutamoren Mesylate) is a potent, long-acting, orally-active growth hormone secretagogue. Unlike injectable peptide GH secretagogues, MK-677 is taken orally and has a half-life of approximately 24 hours, supporting once-daily dosing.

Clinical studies have demonstrated that MK-677 increases GH and IGF-1 levels to those of healthy young adults without altering cortisol levels. A landmark 2-year study in elderly subjects showed significant increases in GH, IGF-1, and fat-free mass with daily oral dosing.

MK-677 has been studied in clinical trials at doses ranging from 5 mg to 50 mg daily. The following are commonly used research protocols:

The 25 mg dose was used in the majority of published clinical trials. Some researchers start at 10 mg for 2–4 weeks to assess tolerance before increasing to 25 mg. Doses above 25 mg have not shown proportionally greater GH elevation.

MK-677 is taken once daily due to its 24-hour half-life. Common timing protocols include:

• Before bed: The most popular approach, as it enhances the natural nocturnal GH pulse and may reduce daytime hunger/lethargy side effects.
• Morning: Some researchers prefer morning dosing to align with the natural circadian GH rhythm.

Cycling: MK-677 can be used for extended periods. Clinical studies have run continuously for up to 2 years. Common cycling approaches include 12 weeks on / 4 weeks off, or continuous use with periodic IGF-1 monitoring. Some researchers cycle 5 days on / 2 days off to manage insulin sensitivity.

MK-677 is an oral compound and does not require reconstitution or injection. It is typically supplied as:

• Capsules: Standard 10 mg or 25 mg capsules taken with water.
• Liquid solution: Measured using a calibrated dropper or oral syringe. Common concentrations are 25 mg/mL.

MK-677 can be taken with or without food, though taking it with a small meal may reduce the initial hunger spike. Store in a cool, dry place away from direct sunlight.

• 10 mg/day: Mild increase in appetite, slight water retention, improved sleep quality.
• 15–20 mg/day: Pronounced appetite increase, moderate water retention and bloating, possible lethargy, numbness/tingling in hands.
• 25 mg/day: Significant appetite stimulation, notable water retention, elevated fasting blood glucose, potential insulin resistance with prolonged use. In clinical trials, fasting glucose increased by ~5 mg/dL on average.

The most clinically significant concern is impaired insulin sensitivity, particularly with long-term use at 25 mg.

MK-677 is an investigational compound that has not received FDA approval.

Monitor fasting blood glucose and HbA1c regularly, especially in insulin-resistant or pre-diabetic subjects. Avoid in subjects with active malignancies due to IGF-1 elevation. Not recommended for subjects with uncontrolled diabetes. Consult a healthcare provider before use.