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Ibutamoren (MK-677)

Peptideoral · inferred

Orally active non-peptide ghrelin receptor (GHSR1a) agonist that mimics ghrelin to stimulate pulsatile growth hormone and IGF-1 secretion. Despite low oral bioavailability (~4%), potent receptor affinity yields clinically meaningful GH/IGF-1 elevation at 10-25 mg/day. Grey-market use for sleep quality, body composition, and recovery among biohackers; never achieved FDA approval despite trials in elderly sarcopenia and hip fracture recovery. Side effects: fluid retention, insulin resistance, increased appetite, lethargy.

Projected serum levels — 15 mg, once daily

Ibutamoren (MK-677)
Ibutamoren (MK-677) modeled serum levels, 15 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 15 mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 0.54 mg, trough ≈ 0.023 mg body load. Population-based estimate over 15 days for a 15 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Peptide
Route modeled
Oral
Model confidence
inferred
Half-life
5 h
Common dose
15 mg
Suggested maximum
25 mg/day
Reference dose range
7.5–25 mg (single dose)
Suggested cadence
once daily
Validated against
25 mg oral — Cmax 0.015 mg/L at 1 h

Documented interactions

  • contraindicated
    Carbamazepine (Tegretol) + Ibutamoren (MK-677) CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Ibutamoren (MK-677) AUC by ~0.20x

  • contraindicated
    Clarithromycin (Biaxin) + Ibutamoren (MK-677) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Ibutamoren (MK-677) AUC by ~10.00x

  • contraindicated
    Dasatinib (Sprycel) + Ibutamoren (MK-677) CYP inhibition

    Dasatinib (Sprycel) time_dependent_inhibitor of CYP3A4 predicted to change Ibutamoren (MK-677) AUC by ~5.00x

  • contraindicated
    Diltiazem + Ibutamoren (MK-677) CYP inhibition

    Diltiazem mechanism_based of CYP3A4 predicted to change Ibutamoren (MK-677) AUC by ~10.00x

  • contraindicated
    Efavirenz (Sustiva) + Ibutamoren (MK-677) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Ibutamoren (MK-677) AUC by ~0.12x

  • contraindicated
    Grapefruit (whole fruit) + Ibutamoren (MK-677) CYP inhibition

    Grapefruit (whole fruit) mechanism_based of CYP3A4 predicted to change Ibutamoren (MK-677) AUC by ~10.00x

Serum checks 80 modeled interaction pairings for ibutamoren (mk-677) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Design and biological activities of L-163,191 (MK-0677): a potent, orally active growth hormone secretagogue Patchett AA et al. · Proceedings of the National Academy of Sciences, 1995 DOI

    Seminal Merck discovery paper describing MK-0677 as a potent, orally active, non-peptidyl growth hormone secretagogue with sustained GH/IGF-1 elevation in animals and humans.

  2. MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism Murphy MG et al. · Journal of Clinical Endocrinology & Metabolism, 1998 DOI

    Clinical study showing 25 mg/day MK-677 for 7 days reversed nitrogen-wasting and increased IGF-1 levels ~60% during caloric restriction, with sustained GH pulse amplitude response.

  3. Oral administration of growth hormone (GH) releasing peptide-mimetic MK-677 stimulates the GH/IGF-I axis in selected GH-deficient adults Chapman IM et al. · Journal of Clinical Endocrinology & Metabolism, 1997 DOI

    Established that chronic MK-677 dosing in older adults restored GH and IGF-1 levels to those of young adults with favorable body composition changes over 2 months.

3 published studies referenced in the app, each with a plain-language summary.