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MK-677

Also known as: Ibutamoren, MK677, Nutrobal

4
1 · Natty510 · Enhanced

Lower numbers = closer to natural. Higher numbers = more enhanced.

Why this rating?

MK-677 is an oral, non-peptide ghrelin-receptor agonist that stimulates the pituitary's own pulsatile GH release rather than replacing GH directly. In the pivotal 2-year RCT in healthy older adults (Nass et al. 2008, Ann Intern Med, PMID 18981485), 25mg/day raised IGF-1 roughly 1.5-fold and modestly increased fat-free mass (+1.1kg vs placebo, driven largely by intracellular water) while also raising fasting glucose and HbA1c and reducing insulin sensitivity. Does not suppress testosterone and requires no PCT. Rated 4, consistent with the other GH secretagogues in this scale (CJC-1295, Ipamorelin, GHRP-2/6, tesamorelin), a genuine step up in GH/IGF-1 exposure beyond natural pulsatile release, but well below exogenous HGH or IGF-1 itself, and its real-world muscle-building effect is modest relative to its metabolic cost.

Overview

An oral ghrelin mimetic that stimulates GH pulses. Technically not a peptide but a non-peptide agonist of the ghrelin receptor that increases growth hormone and IGF-1 levels.

Important Warnings

  • •Can significantly impair blood glucose - monitor regularly
  • •Not suitable for diabetics or pre-diabetics
  • •A 2-year RCT (Nass et al. 2008) found the fasting glucose/HbA1c increase and reduced insulin sensitivity persisted for the full study duration - this is not a short-term adaptation effect

Purpose & Use Cases

Increased IGF-1

Elevates IGF-1 levels for enhanced recovery and growth.

Improved Sleep

Significantly enhances sleep quality, particularly REM and deep sleep.

Appetite Stimulation

Dramatically increases appetite, useful for hardgainers.

Benefits

  • Oral administration (no injections)
  • Improved sleep quality
  • Increased appetite
  • Elevated IGF-1 levels
  • Enhanced recovery
  • Improved skin and hair

Good to Know

It is a ghrelin mimetic, not GH, and not a SARM

MK-677 does not add growth hormone. It activates the ghrelin receptor so your own pituitary releases GH in natural pulses. That is why it is oral, why it drives hunger (ghrelin is the hunger hormone), and why its IGF-1 bump is real but gentler than injectable HGH.

The blood-sugar cost is the real catch

The GH/IGF-1 rise reliably worsens insulin sensitivity and raises fasting glucose. This is the effect to actually manage, monitor glucose/HbA1c and use berberine, rather than the water retention or hunger, which are mostly cosmetic.

Not suppressive: no PCT, can run long

Unlike steroids or SARMs, MK-677 does not touch the HPTA, so no PCT is needed and it can run for extended periods (glucose permitting). Its most reliable benefits are deeper sleep and recovery, not muscle per se.

Dosage Guidelines

Experience LevelDosage Range
Beginner12.5 – 12.5 mg/day
Intermediate12.5 – 25 mg/day
Advanced25 – 25 mg/day
Frequency
Daily oral, usually before bed
Typical Cycle Length
8 – 12 weeks
Notes

Can be run longer but 8-12 weeks is typical. Monitor blood glucose.

Half-Life

The often-cited ~4-6h plasma elimination half-life is derived from animal (canine) pharmacokinetic data rather than a confirmed human PK study; the GH/IGF-1 elevation itself lasts roughly 24h in humans with once-daily oral dosing (single-dose data).

Side Effects

Elevated Blood Glucose

very common
Severity
3/5

Reliably impairs glucose tolerance and insulin sensitivity. In the 2-year RCT (Nass et al. 2008) fasting glucose rose ~5mg/dL (0.3mmol/L) and HbA1c by 0.2% at 25mg/day, with a significant decline in insulin sensitivity (QUICKI index); a 4-week dose-ranging study similarly found significant fasting-glucose increases at 25mg/day.

Mitigation

Low-carb diet; monitor fasting glucose; consider Berberine.

Water Retention

very common
Severity
2/5

Mild, typically transient lower-extremity edema/bloating. In the 2-year RCT it occurred in 44% of MK-677 users vs 27% on placebo, described as mild and transient rather than severe.

Mitigation

Usually manageable; reduce dose if excessive.

Extreme Hunger

very common
Severity
2/5

Significantly increased appetite, can make dieting difficult.

Mitigation

Time dosing for before bed to sleep through worst hunger.

Lethargy

common
Severity
2/5

Some users experience daytime sleepiness.

Mitigation

Take before bed; adjust timing if needed.

General Mitigation Strategies

Low-carb diet to manage blood glucose. Take before bed to minimize hunger issues. Monitor fasting glucose regularly. A home glucometer or CGM is the single most useful "support supplement". Track fasting glucose, fasting insulin/HOMA-IR and HbA1c, and add berberine (or discontinue) if numbers trend toward prediabetic.

Support Supplements

Ancillary supplements commonly run alongside MK-677 to manage side effects, support the target tissue, or fill nutrient demands it creates.

Berberine

Key

Counters the elevated fasting glucose and insulin resistance MK-677 causes (a GH effect). Acts as an AMPK activator with a "metformin-like" glucose-lowering profile.

Dose
500mg, 2-3x daily (1,000-1,500mg/day total)
Timing
15-30 min before carb-containing meals
When
The one genuinely evidence-based support for MK-677. Still monitor glucose/HbA1c: berberine blunts but does not eliminate the effect. Additive hypoglycemia risk with metformin/insulin; strong CYP3A4/P-gp inhibitor (interacts with statins and many drugs).

P5P (Vitamin B6)

Popularly recommended to "control prolactin and water retention" from MK-677.

Dose
25-50mg/day if used
Timing
With food
When
Weak rationale: MK-677 does not reliably raise prolactin in clinical data, and B6's anti-edema evidence is PMS-specific. Largely optional/bro-science for this purpose. Avoid chronic high doses (>100-200mg/day): risk of sensory peripheral neuropathy.

Post Cycle Therapy (PCT)

✓PCT Not Required

Does not suppress testosterone. No PCT required.

How It Works

MK-677 mimics ghrelin and binds to ghrelin receptors in the brain, stimulating the pituitary to release growth hormone. Unlike injectable GH, it promotes natural pulsatile GH release patterns.

Fundamentals

Reference on the practices relevant to MK-677: how they are done and where they go wrong. Not a recommendation to use it.

Reconstitution & concentration math→

Turning this powder into a measured dose

Bloodwork: what to measure and when→

The markers that matter here

Warning signs & when to seek care→

When to stop and get help

Common Stacks

  • MK-677 + SARMs - Enhanced recovery and growth
  • MK-677 + Testosterone - Synergistic mass building

WADA Status

⛔Prohibited by WADA
Category: S2. Peptide Hormones, Growth Factors, Related Substances and Mimetics
In-Competition: ProhibitedOut-of-Competition: Prohibited

Ibutamoren (MK-677) is prohibited at all times under WADA category S2 as a growth hormone secretagogue.

References

Last updated: July 18, 2026