MK 677 (Ibutamoren)

MK-677 (Ibutamoren) 25mg by Dragon Pharma

MK-677 (Ibutamoren) is Dragon Pharma's oral formulation of a non-peptide GHS-R1a ghrelin mimetic at 25mg per tablet — the only orally bioavailable growth hormone secretagogue with a ~24-hour half-life available in the Dragon Pharma range. Unlike injectable GH peptides (Ipamorelin, CJC-1295, Sermorelin), MK-677 is a small molecule that requires no reconstitution, no refrigeration and no injection, while producing sustained GH and IGF-1 elevation that persists throughout the day from a single daily dose.

Also searched as: MK677, Ibutamoren 25mg, MK 677 oral GH, Ibutamoren Dragon Pharma, oral growth hormone secretagogue.

What MK-677 Is — The Critical Classification

MK-677 is frequently misclassified by competitor content — typically as a SARM or as a peptide. It is neither:

• Not a SARM: MK-677 does not bind androgen receptors. It has no anabolic steroid-like activity, produces no testosterone suppression and requires no PCT
• Not a peptide: Unlike injectable GH secretagogues (Ipamorelin, CJC-1295, Sermorelin, Tesamorelin), MK-677 is a non-peptide small molecule — a spiropiperidine that mimics ghrelin at the GHS-R1a receptor. Its small molecule structure is what enables oral bioavailability; peptides are degraded by digestive enzymes before absorption
• What it actually is: A selective GHS-R1a (growth hormone secretagogue receptor 1a) agonist that mimics ghrelin — the hunger hormone — at the pituitary and hypothalamus, stimulating GH release through the same receptor pathway as injectable GHRP peptides but via an orally stable molecule with a 24-hour half-life

The GHS-R1a Mechanism — How MK-677 Elevates GH and IGF-1

MK-677 activates GHS-R1a (the ghrelin receptor) in the pituitary and hypothalamus, producing two complementary effects on GH release:

• Direct pituitary GH release: GHS-R1a activation in somatotroph cells directly stimulates GH secretion — the same receptor targeted by injectable GHRP peptides (Ipamorelin, GHRP-2, GHRP-6)
• Hypothalamic GHRH amplification: GHS-R1a activation in the hypothalamus stimulates GHRH (growth hormone releasing hormone) release, which then acts on the pituitary to further amplify GH output — a synergistic two-level mechanism
• The result is sustained, supra-physiological GH pulses that persist throughout the day due to MK-677's 24-hour half-life. Unlike injectable GH peptides with half-lives of minutes to hours, MK-677 maintains GHS-R1a stimulation continuously — producing a chronic GH elevation rather than discrete pulses

The Clinical IGF-1 Data

MK-677 has one of the most robust clinical evidence bases of any GH secretagogue — with specific IGF-1 elevation numbers from human trials:

• Copinschi et al. (1996, American Journal of Physiology): 25mg/day MK-677 for 2 weeks in healthy young men produced a 60-72% increase in IGF-1 above baseline — sustained over the treatment period
• Murphy et al. (1998): 25mg/day in healthy elderly subjects produced comparable IGF-1 elevation and significantly improved slow-wave (deep) sleep quality — a consistent finding across MK-677 trials
• Nass et al. (2008, Annals of Internal Medicine): 25mg/day for 2 years in healthy elderly subjects maintained IGF-1 in the young-adult reference range throughout — demonstrating sustained efficacy without tachyphylaxis
• Svensson et al. (1998): MK-677's GH-stimulating effect was maintained for the full 12-month study period — receptor downregulation does not occur with continued use, unlike beta-2 agonists

MK-677 vs Injectable GH Secretagogues — The Comparison

The Water Retention and Insulin Resistance Consideration

Two side effects of MK-677 that competitor content consistently underrepresents:

• Water retention: MK-677's sustained GH elevation increases aldosterone activity and sodium retention. Water retention of 2-4kg is common, particularly in the first 4-8 weeks. This subsides partially but often persists throughout use — making MK-677 less suitable for cutting phases where a dry, lean appearance is the goal
• Insulin resistance: Sustained GH elevation (as opposed to the pulsatile physiological pattern) can cause mild insulin resistance over time through GH's counter-regulatory insulin effects. In healthy users this is typically not clinically significant short-term, but blood glucose monitoring is advisable for extended use (6+ months) and for users with pre-existing glucose management concerns
• Both effects are dose-dependent — users sensitive to water retention sometimes use 12.5mg/day (half tablet) rather than 25mg to reduce these while maintaining meaningful GH elevation

Effects and Benefits

• 60-72% IGF-1 elevation above baseline from clinical trial data at 25mg/day
• Significant improvement in deep sleep (slow-wave sleep) — consistently documented in MK-677 trials; the GH elevation during sleep is amplified
• Enhanced recovery — GH and IGF-1 elevation support muscle repair and connective tissue maintenance
• No injection required — the only oral GH secretagogue with sustained once-daily action
• No receptor downregulation — efficacy maintained across 2-year clinical studies
• No testosterone suppression — no PCT required

Dosage and Administration

Evening dosing aligns MK-677's GH peak with the natural nocturnal GH pulse, amplifying sleep-stage GH release. The 24-hour half-life means the daily dose maintains continuous GHS-R1a stimulation — MK-677 reaches steady-state over approximately 4 days and effects are sustained without cycling. Unlike beta-2 agonists, no 2-week on/off cycling is needed. Long-term protocols of 6-12 months are common given the 2-year safety data from clinical trials.