MK-677 Dosage, half-life & reference guide
Also known as Ibutamoren · Nutrobal · MK677 · Ibutamoren Mesylate
Not actually a peptide — it's a small molecule you take orally that mimics ghrelin to stimulate GH release. The convenience of a daily pill instead of injections makes it popular.
- Studied range
- 10–25 mgstarting dose 10 mg
- How often
- Daily
- Half-life
- ~24 hours
- Evidence
- ●●
●Moderate - Route
- Oral
Studied in research — not a recommendation.
How it works.
Orally active ghrelin receptor agonist and GH secretagogue. Stimulates GH and IGF-1 with little short-term effect on cortisol (a small rise over a year). Its long-lasting effect on GH and IGF-1 allows once-daily oral dosing. Significantly increases appetite and promotes deep sleep. MK-677 is a small molecule GH secretagogue, not a peptide — included because it is extremely commonly tracked alongside peptide GH protocols.
Commonly reported: Strong hunger, especially in the first weeks; water retention with puffy hands and feet or tingling hands; and deeper sleep with vivid dreams, sometimes with morning grogginess. Once-daily dosing boosts natural GH pulses and keeps IGF-1 elevated.
Half-life & active level
The half-life of MK-677 is ~24 hours (community estimate; no half-life has been published for people: in dogs it was 4–6 hours, and its effect on GH and IGF-1 lasts about a day).
Here's how a typical MK-677 schedule accumulates over a week (one-compartment estimate).
An estimate from the half-life above, not a measurement. See your own curve build live in the half-life calculator.
Where MK-677 works.
Brain, nerves & sleep
In people. In a sleep-lab study MK-677 lengthened deep (stage IV) sleep by about 50% and REM sleep by 20–50%.
Muscle
In people. In trials, lean mass rose over the first year, so if nutrition is dialed, gains show up here.
Energy & longevity
In people. Stimulates GH and IGF-1 with little short-term effect on cortisol (a small rise over a year).
An area lights for what a peptide is used for and what people report, with the evidence beside it. It isn’t a promise that it works there.
Week by week.
What to expect in the first 8 weeks
- Onset
- 1–3 days
- Peak effect
- 8–12 weeks
- Duration
- 8–16 weeks
Day 1–14Community
Hunger up, sleep deeper, water on
The first two weeks are the adjustment phase. Commonly reported: appetite surges almost immediately, sleep gets vivid and dense, and water retention nudges the scale up. It usually settles by week 3.
The science
MK-677 (Ibutamoren) is a non-peptide ghrelin receptor agonist whose effect lasts about 24 hours. In older adults, 25 mg/day roughly doubled 24-hour GH by week 2 and lifted IGF-1 into the young-adult range (Chapman et al. 1996). The water retention comes from GH's sodium-retaining effect.
Sources- Chapman et al. (1996)
Updated Sep 2026
Day 14–56RCT
Lean mass is climbing
Commonly reported: water retention settles, appetite steadies, sleep is noticeably deeper, skin and hair improve and training recovery jumps. In trials, lean mass rose over the first year, so if nutrition is dialed, gains show up here.
The science
Nass et al. 2008 (2yr RCT, n=65, elderly adults) documented sustained IGF-1 elevation and ~1.1kg lean mass gain at 1 year, though the extra lean mass didn't change strength or function, and limb fat rose too. In a sleep-lab study, MK-677 lengthened deep (stage IV) sleep about 50% and REM sleep 20–50% (Copinschi 1997). Monitor fasting glucose around week 6–8.
Sources- Nass et al. (2008)
- Copinschi et al. (1997)
Updated Sep 2026
Day 56–90RCT
Check your labs — glucose is the watch item
If you've been running this continuously, pull fasting glucose and HbA1c now. The clinically relevant tradeoff with MK-677 is a rise in fasting glucose (about +5 mg/dL on average in the 2-year trial, more in some shorter studies) plus reduced insulin sensitivity. How quickly it reverses after stopping hasn't been studied, so you want to catch the drift before it matters. Assess gains and metabolic markers together.
The science
In the 2-year trial in older adults, fasting glucose rose about 5 mg/dL on average, with reduced insulin sensitivity (Nass et al. 2008); in a 4-week study at 25 mg/day it rose from 5.4 to 6.8 mmol/L (Chapman et al. 1996). A hip-fracture trial in frail older adults was stopped early over a heart-failure signal (Adunsky 2011). These are the reasons the glucose and cardiac considerations sit at the center of MK-677's risk picture — monitor, don't ignore.
Sources- Nass et al. (2008)
- Chapman et al. (1996)
- Adunsky et al. (2011)
Updated Sep 2026
Any dayRCT
What MK-677 is built on
MK-677 has more human clinical data than most peptides tracked here — including a 2-year RCT in older adults. Also the only oral option in this space. Trade-off: glucose regulation and water retention are real, and long-term metabolic effects need monitoring.
The science
Originally developed by Merck for muscle wasting and osteoporosis. Multiple phase 2 trials with published safety and efficacy data. Now investigational/research-only in the US but widely tracked, and FDA lists it in compounding category 2. Small-molecule drug rather than a peptide — technically outside the peptide category but universally dosed alongside peptide GH protocols.
Sources- Nass et al. (2008)
- Chapman et al. (1996)
Updated Sep 2026
With CJC-1295 and IpamorelinCommunity
Orals + injectables for broader GH coverage
Common stack: MK-677's once-daily dose keeps IGF-1 up and lifts GH pulses and troughs, while injected CJC-1295 adds GHRH-receptor stimulation on top. Ipamorelin works on the same receptor as MK-677, so that pairing overlaps. Commonly reported: the side effects add up, with more water retention and hunger than either alone.
The science
MK-677 and Ipamorelin both act on GHS-R1a (the ghrelin receptor); CJC-1295 acts on the GHRH receptor. Co-activating the two pathways produced synergistic GH release in human studies (Bowers 1990, with GHRP-6 and GHRH). The practical downside is redundant tolerability issues (water retention, appetite, glucose).
Sources- Bowers et al. (1990)
Updated Sep 2026
Day 1 is the day you start it.
Multiple clinical studies including 2-year elderly study. Well-characterized oral GH secretagogue.
Moderate evidence
A typical run.
Run notes
- Cycle
- Continuous use common (oral convenience). Some cycle 3 months on / 1 month off. Long-term safety data limited.Community practice — opinions vary. Not a clinical recommendation.
- Timing
- Once daily before bed. Food increases appetite side effect — empty stomach preferred by some.
- Route
- Oral
- Stacks
- CJC-1295 no DAC, Ipamorelin
Safety.
Common side effects
- Increased appetite
- Water retention
- Lethargy
- Elevated fasting glucose
- Vivid dreams
- Carpal tunnel symptoms
Goes with.
Compared with.
Questions people ask.
What is MK-677?
Not actually a peptide — it's a small molecule you take orally that mimics ghrelin to stimulate GH release. The convenience of a daily pill instead of injections makes it popular.
How is MK-677 dosed in research?
The research range for MK-677 is 10–25 mg, daily, before bed, with a 10 mg starting dose. Studied in research — not a recommendation.
How long does MK-677 last?
The half-life of MK-677 is ~24 hours (community estimate; no half-life has been published for people: in dogs it was 4–6 hours, and its effect on GH and IGF-1 lasts about a day).
What do people report on MK-677?
Commonly reported on MK-677: strong hunger, especially in the first weeks; water retention with puffy hands and feet or tingling hands; and deeper sleep with vivid dreams, sometimes with morning grogginess. Once-daily dosing boosts natural GH pulses and keeps IGF-1 elevated.
Is MK-677 safe?
The research basis for MK-677 is moderate: animal studies + some human data. Common side effects in the library: increased appetite, water retention, lethargy, elevated fasting glucose, vivid dreams and carpal tunnel symptoms.
What does MK-677 stack with?
Common stacks for MK-677: CJC-1295 no DAC and Ipamorelin.
Research.
Reference.
- Cadence
Daily
Daily, before bed
- Half-life
~24 hours
~24 hours (community estimate; no half-life has been published for people: in dogs it was 4–6 hours, and its effect on GH and IGF-1 lasts about a day)
- Research basis
●●
●ModerateAnimal studies + some human data
PepVault for iPhone
Track MK-677 in PepVault
Log every dose and watch its estimated active level. 7 days free on the yearly plan for new subscribers.
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