MK-677
Tested in peopleGet notified when the evidence changes.
It has been tested in people, but it is not an approved medicine. The studies are usually small.
Compiled and reviewed by the PeptideSearch Editorial Team · Status checked 2026-05-14
Also called Ibutamoren / Ibutamoren mesylate / MK-0677 / Nutrobal
A pill, not a peptide. Raises growth hormone and IGF-1. Tested in people but never approved.
Official status: 503A Category 2 – significant safety risk · Checked 2026-05-14
Can a doctor prescribe this?
- Small pharmacy (503A)
- Category 2 — FDA flagged a safety concern
- Large outsourcing facility (503B)
- Category 2 — FDA flagged a safety concern
The FDA has "Ibutamoren Mesylate" — the chemical name for MK-677 — in Category 2 of the substances put forward for small-pharmacy (503A) compounding: the group it says raises a real safety concern. Pharmacies are not allowed to make it.
503A is a pharmacy making a single prescription for one patient. 503B is a facility making batches. They are governed by separate lists. Where a category is shown, it is a position on the FDA's list of substances that have been put forward and are still being worked through — not the final list, which is set by rulemaking. Category 1 means the FDA does not plan to act against a pharmacy that makes it while the review runs.
Lab suppliers we list: 9
Doses used in research
Taken word for word from the studies and trials listed on this page. This is not a recommendation and not a dose for anyone to take.
- Study in peopleOral ghrelin receptor agonist MK-0677 increases serum insulin-like growth factor 1 in hemodialysis patients: a randomized blinded study.
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association · 2018
- Study in peopleMK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study.
Archives of gerontology and geriatrics · 2011
- Study in peopleGrowth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial.
Neurology · 2008
- Study in peopleEffects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial.
Annals of internal medicine · 2008
- Study in peopleThe effects of MK-0677, an oral growth hormone secretagogue, in patients with hip fracture.
Journal of the American Geriatrics Society · 2004
- Study in peopleEffect of alendronate and MK-677 (a growth hormone secretagogue), individually and in combination, on markers of bone turnover and bone mineral density in postmenopausal osteoporotic women.
The Journal of clinical endocrinology and metabolism · 2001
- Study in peopleOral administration of the growth hormone secretagogue MK-677 increases markers of bone turnover in healthy and functionally impaired elderly adults. The MK-677 Study Group.
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research · 1999
- Study in peopleDiscrepancy between serum leptin values and total body fat in response to the oral growth hormone secretagogue MK-677.
Clinical endocrinology · 1999
- Study in peopleTreatment of obese subjects with the oral growth hormone secretagogue MK-677 affects serum concentrations of several lipoproteins, but not lipoprotein(a).
The Journal of clinical endocrinology and metabolism · 1999
- Study in peopleMK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism.
The Journal of clinical endocrinology and metabolism · 1998
- Study in peopleTreatment with the oral growth hormone secretagogue MK-677 increases markers of bone formation and bone resorption in obese young males.
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research · 1998
- Study in peopleTwo-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure.
The Journal of clinical endocrinology and metabolism · 1998
- Study in peopleProlonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man.
Neuroendocrinology · 1997
- Study in peopleOral administration of growth hormone (GH) releasing peptide-mimetic MK-677 stimulates the GH/insulin-like growth factor-I axis in selected GH-deficient adults.
The Journal of clinical endocrinology and metabolism · 1997
- Study in peopleStimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretogogue (MK-677) in healthy elderly subjects.
The Journal of clinical endocrinology and metabolism · 1996
- Study in peopleEffects of a 7-day treatment with a novel, orally active, growth hormone (GH) secretagogue, MK-677, on 24-hour GH profiles, insulin-like growth factor I, and adrenocortical function in normal young men.
The Journal of clinical endocrinology and metabolism · 1996
- Data from people, not a trialHepatotoxicity induced by MK-677.
BMJ case reports · 2025
- Data from people, not a trialReversible Gynecomastia and Hypogonadism Due to Usage of Commercial Performance-Enhancing Supplement Use.
JCEM case reports · 2024
- Data from people, not a trialLGD-4033 and MK-677 use impacts body composition, circulating biomarkers, and skeletal muscle androgenic hormone and receptor content: A case report.
Experimental physiology · 2022
- Animal study, rats or miceAcute stress suppresses hunger-driven food seeking through PVN activation: Reversal by anxiolytic drug and ghrelin receptor agonist, with anxiolytic-like effects of refeeding.
Neuroscience research · 2026
- Animal study, rats or miceStriosomal ghrelin receptor activity controls reward-cost integration
2026
- Animal study, rats or miceIntranasal Delivery of a Ghrelin Mimetic Engages the Brain Ghrelin Signaling System in Mice.
Endocrinology · 2025
- Horse studyEquine metabolism of the growth hormone secretagogue MK-0677 in vitro and in urine and plasma following oral administration.
Drug testing and analysis · 2022
- Horse studyCharacterization of equine liver microsome-generated metabolites of growth hormone secretagogue small molecule ibutamoren.
Rapid communications in mass spectrometry : RCM · 2021
- Animal study, rats or miceBrain and kidney GHS-R1a underexpression is associated with changes in renal function and hemodynamics during neurogenic hypertension.
Molecular and cellular endocrinology · 2020
- Animal study, rats or miceEffect of the Orally Active Growth Hormone Secretagogue MK-677 on Somatic Growth in Rats.
Yonsei medical journal · 2018
- Animal study, rats or miceMK-0677, a Ghrelin Agonist, Alleviates Amyloid Beta-Related Pathology in 5XFAD Mice, an Animal Model of Alzheimer's Disease.
International journal of molecular sciences · 2018
- Lab dish studyBinding Domain Characterization of Growth Hormone Secretagogue Receptor.
Journal of translational internal medicine · 2022
- Lab test method, not a health studyRapid and harmonized analytical workflow for the determination of peptidic and non-peptidic doping agents in dried and liquid blood matrices.
The Analyst · 2026
- Lab test method, not a health studyDetection of the growth hormone secretagogue MK-0677 in equine hair following oral administration.
Drug testing and analysis · 2023
- Lab test method, not a health studyCharacterization of growth hormone secretagogue small molecule ibutamoren (MK-0677) and its possible metabolites in thoroughbred horses for doping control.
Rapid communications in mass spectrometry : RCM · 2022
- Hypothesis, not a tested studyNew directions in growth hormone treatment in children.
Pediatric endocrinology, diabetes, and metabolism · 2025
- Knowing the minimal detectable dose can facilitate the interpretation of a hair test result: II. Case example with ibutamoren (MK-677), a growth hormone secretagogue.
Clinica chimica acta; international journal of clinical chemistry · 2026
- A GH Secretagogue Receptor Agonist (LUM-201) Elicits Greater GH Responses than Standard GH Secretagogues in Subjects of a Pediatric GH Deficiency Trial.
Hormone research in paediatrics · 2022
- Antiviral activity of sertindole, raloxifene and ibutamoren against transcription and replication-competent Ebola virus-like particles.
BMB reports · 2020
- The Safety and Efficacy of Growth Hormone Secretagogues.
Sexual medicine reviews · 2018
- The effect of treatment with the oral growth hormone (GH) secretagogue MK-677 on GH isoforms.
Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society · 2003
- Effects of oral administration of ibutamoren mesylate, a nonpeptide growth hormone secretagogue, on the growth hormone-insulin-like growth factor I axis in growth hormone-deficient children.
Clinical pharmacology and therapeutics · 2001
- Recombinant human IGF-I does not modify the ACTH and cortisol responses to hCRH and hexarelin, a peptidyl GH secretagogue, in humans.
Journal of endocrinological investigation · 2001
- Review of earlier workSpontaneous Splenic Rupture in a Patient With Recent Use of Performance-Enhancing Compounds: A Case Report and Literature Review.
Cureus · 2026
- Review of earlier workPeptide Supplements and Their Therapeutic Applications in Sports Medicine.
The American journal of sports medicine · 2026
- Review of earlier workInvestigating the P53-dependent anti-cancer effect of ibutamoren in human cancer cell lines.
Basic & clinical pharmacology & toxicology · 2025
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What has happened so far
- 14 May 2026503A
FDA lists "Ibutamoren Mesylate" — MK-677 — under 503A Category 2: Bulk Drug Substances that Raise Significant Safety Risks. Read from the FDA 503A category document headed "Updated May 14, 2026".
- 21 March 2025503B
FDA lists "Ibutamoren Mesylate" — MK-677 — under 503B Category 2: Bulk Drug Substances that Raise Significant Safety Risks. Read from the FDA 503B category document dated March 21, 2025.