MK-677

Areas of active research — not promised effects

Each tag links to other compounds with research into that goal. Research use only: these are areas of study, not human-use claims.

Related by research scope · open each to compare

MK-677 (ibutamoren) is not an FDA-approved drug and has no marketing authorisation in the United States. It carried the FDA-19 flag, placing it under ongoing FDA oversight of bulk peptide compounding. FDA placed ibutamoren mesylate in Category 2 of the interim 503A bulk drug substances policy on 2023-09-29 (503B Category 2: 2022-12-29) — the same policy category as BPC-157 — citing a potential congestive-heart-failure safety risk; this bars 503A pharmacies from compounding it for human use. On 2024-10-29, the FDA Pharmacy Compounding Advisory Committee (PCAC) voted 13-1 against adding ibutamoren mesylate to the 503A Bulks List (docket FDA-2024-N-4188), consistent with FDA's own non-inclusion proposal; dissenting (no) voters cited insufficient efficacy/safety evidence and fluid-retention, congestive-heart-failure and hyperglycemia signals. That vote is a non-binding advisory recommendation, not a ban. In April 2026, FDA removed a batch of twelve OTHER peptides (BPC-157, KPV, TB-500, MOTS-c, DSIP/Emideltide, Semax, Epitalon, GHK-Cu, Melanotan II, LL-37, Dihexa, MGF/PEG-MGF) from Category 2 — ibutamoren mesylate, a non-peptide small molecule, was NOT among them and remains in active Category 2 as of FDA's Category 2 bulk-substances page (content current 04/22/2026, confirmed via Wayback archive 2026-05-18/06-08). No ibutamoren-specific PCAC re-review is currently scheduled; the announced July 23-24, 2026 PCAC session covers only BPC-157, TB-500, KPV, MOTS-c, Emideltide, Semax and Epitalon. Sale is legally restricted to licensed research institutions for non-clinical research use only (RUO).

Confirmed high-severity market-integrity event (enforcement / recall / counterfeit)

Transparent blend · bci-1.0 · never paid-placement

Primary name

MK-677

Origin

MK-677 (ibutamoren; MK-0677) is a synthetic non-peptide spiropiperidine compound first synthesised in 1995 by Arthur Patchett and colleagues at Merck Research Laboratories. It was designed to be orally bioavailable — overcoming the parenteral requirement of peptide GHRPs — while retaining full agonist activity at the growth hormone secretagogue receptor type 1a (GHS-R1a, the ghrelin receptor). MK-677 does not correspond to any endogenous peptide sequence; its spiropiperidine scaffold is a fully synthetic pharmacophore optimised for receptor selectivity and oral absorption.

Registry IDs

PubChem CID

6450830

CAS

159752-10-0

InChIKey

DUGMCDWNXXFHDE-VZYDHVRKSA-N

ChEMBL

CHEMBL2105872

Molecular formula

C28H40N4O8S2

Molar mass

624.8 g/mol

Monoisotopic

624.22875659 Da

InChIKey

DUGMCDWNXXFHDE-VZYDHVRKSA-N

Appearance

White to off-white lyophilised or crystalline solid (typically supplied as the mesylate salt)

Solubility

Soluble in water and dimethyl sulfoxide (DMSO); oral bioavailability 60–70% in e…

Sequence not available in current seed.

Stability: Stable as a solid under cold and dry conditions. In solution, susceptible to hydrolysis and degradation at elevated temperatures or extreme pH; store prepared s

Vial sizes

10 mg · 30 mg

Purity grades

≥98% HPLC

Salt forms

Free base (primary)

• GHS hazard class on file
• PPE & spill response
• Disposal guidance
• Not-for-human-consumption posture

How much research exists, and of what maturity — never a verdict on whether it works.

Mechanism of action

• MK-677 acts as a full, selective agonist at GHS-R1a, the Gq/11-coupled G-protein-coupled receptor for ghrelin, expressed predominantly on anterior pituitary somatotrophs and hypothalamic arcuate-nucleus neurons
• Upon oral absorption and systemic distribution, it engages GHS-R1a to activate phospholipase C, generating inositol trisphosphate and mobilising intracellular calcium, which triggers exocytosis of stored growth hormone from pituitary somatotrophs
• MK-677 also modulates hypothalamic somatostatin tone, thereby amplifying both the frequency and amplitude of endogenous GH pulses without exogenous GH administration
• Sustained receptor activation elevates downstream circulating IGF-1 over a 24-hour window following a single oral dose, reflecting the compound's extended pharmacodynamic footprint relative to its molecular elimination half-life

Pharmacokinetics (ADME)

Half-life

~4–6 hours (molecular elimination); pharmacodynamic GH/IGF-1 effects sustained approximately 24 hours after a single oral dose

Clearance

Primarily hepatic metabolism and renal excretion; formal population PK data in large cohorts are limited

PK–PD note: Peak plasma concentrations are reached within 1–3 hours of oral administration. Despite a molecular elimination half-life of approximately 4–6 hours, a single 25 mg oral dose maintains IGF-1 levels si…

Reading the evidence

• Evidence quality and gaps vary by application — see the cited grades above.
• Indexed-article counts span all evidence tiers, not only completed human trials.
• No first-party human-dosing, efficacy, or benefit claims are made here.

Key reviews & evidence-gap sources

• Sigalos & Pastuszak 2018 — The Safety and Efficacy of Growth Hormone Secretagogues (Sex Med Rev) — Narrative review of the GH-secretagogue class centering ibutamoren/MK-677; reports lean-mass/appetite/bone-turnover/sleep signals but flags long-term safety (glucose, cancer incidence) as unresolved. Not a PRISMA systematic review.
• Nass et al. 2008 — 2-year RCT of oral MK-677 in healthy older adults (Ann Intern Med) — Verified: COMPLETED, results published (NCT00474279), n=65. GH/IGF-1 and fat-free-mass increases; no effect on muscle strength/function; insulin sensitivity decreased. Reported as cited Layer-A literature, not efficacy.
• Sevigny et al. 2008 — MK-677 no clinical effect on Alzheimer disease progression (Neurology) — Verified: COMPLETED, results published (NCT00074529, Merck Protocol 0677-030), n=563. NEGATIVE efficacy result despite IGF-1 target engagement — a completed human RCT counts toward the RCT tally regardless of outcome. (The 'SYNAPSE' name sometimes attached to this trial is unsupported and dropped — see regulatory timeline note.)
• Campbell et al. 2018 — Oral MK-0677 increases serum IGF-1 in hemodialysis patients, randomized blinded study (Nephrol Dial Transplant) — Verified: COMPLETED, results published (NCT00395291), n=26 (22 completers); registry lists total enrollment 49.
• Adunsky et al. 2011 — MK-0677 for patients recovering from hip fracture, multicenter Phase IIb (Arch Gerontol Geriatr) — Verified: NCT00128115, n=123 randomized (62 MK-0677 / 61 placebo). TERMINATED early on a congestive-heart-failure signal (full text: 4/62 ≈6.5% vs 1/61 ≈1.7%; the abstract says only 'a limited number of patients') but full functional/biochemical results were published — status TERMINATED_WITH_RESULTS, resultsPublished:true per this repo's evidence-strength convention. Safety-halted, largely negative efficacy.
• OraGrowtH210 (LUM-201) — Phase 2 study of ibutamoren in pediatric growth hormone deficiency — [Verification corrected] LUM-201 IS ibutamoren/MK-677 — the same molecule (Lumos Pharma pipeline: 'LUM-201, also known as ibutamoren'; PubChem/CAS 159752-10-0 equate MK-677/MK-0677/ibutamoren mesylate/LUM-201), NOT a 'closely related compound' as the seed FAQ states. This trial is COMPLETED (2024-09-04) with results POSTED 2026-06-17 — a materially under-counted completed human RCT of MK-677. Precision: it is a randomized OPEN-LABEL, ACTIVE-CONTROL (vs rhGH Norditropin) efficacy trial, NOT a double-blind placebo-controlled RCT.

5 registered trials — 1 currently recruiting.

Phase 2
NCT01343641
Growth Hormone Secretagogue MK-0677's Effect on Lean Body Mass in Chronic Kidney Disease Stage 4/5 Subjects

WITHDRAWN

Phase 3
NCT06948214
Phase 3 Study of LUM-201 in Children With Growth Hormone Deficiency

RECRUITING

Phase 2
NCT00116129
Efficacy and Safety of an Oral Growth Hormone Drug in the Treatment of Fibromyalgia

COMPLETED

NA
NCT00395291
Growth Hormone Secretagogue MK-0677 Effect on IGF-1 Levels in ESRD Patients

COMPLETED

Phase 2
NCT00128115
Treatment of Sarcopenia in Post-Hip Fracture Patients (0677-032)

TERMINATED

Summary (literature)

Across clinical trials, the most consistently reported adverse effect of MK-677 is appetite stimulation, observed in the majority of treated participants and most pronounced during initial treatment weeks; this is a direct pharmacodynamic consequence of GHS-R1a agonism (the ghrel…

WADA status

Prohibited at all times (in- and out-of-competition) under WADA 2026 Prohibited List, Section S2 — Peptide Hormones, Growth Factors, Related Substances and Mime…

Dominant research route: Oral (capsule or oral solution) is the only route with meaningful published research located this pass. Every completed human trial found — Chapman 1996 (healthy elderly, JCEM); Chapman 1997 (GH-deficient men, JCEM); MK-677 Study Group / Murphy 1999 (bone turnover, elderly); Svensson 1998 (obese men); Murphy 1998 (diet-induced catabolism); Codner 2001 (pediatric GH deficiency); Nass 2008 (2-year RCT, healthy older adults, Ann Intern Med); and Adunsky 2011 (Phase IIb, hip-fracture patients, stopped early for a cardiac-safety signal) — dosed MK-677 by mouth. Consistent with its design as a non-peptide, GI-stable ghrelin-receptor agonist (Patchett et al. 1995, PNAS). No published parenteral (SC/IM/IV/IP) or intranasal/topical human or controlled-animal comparator study was located.

The dominant — and, in the sources found this pass, essentially the ONLY — clinically studied route. Completed, published human RCTs across healthy elderly (Chapman 1996), severely GH-deficient men (Chapman 1997), elderly bone-turnover (MK-677 Study Group 1999), obese men (Svensson 1998), diet-induced catabolism (Murphy 1998), prepubertal children with idiopathic GH deficiency (Codner 2001), a 2-year RCT in healthy older adults (Nass 2008, Ann Intern Med) and a multicenter Phase IIb RCT in 123 hip-fracture patients (Adunsky 2011) terminated early on a higher CHF rate in the MK-677 arm. Preclinical oral dosing also reported in rats (Yonsei Med J 2018, 4 mg/kg × 6 weeks) and Thoroughbred racehorses (equine doping-control metabolism study, Cutler 2022).

Bioavailability: MK-677 is a synthetic non-peptide (spiropiperidine) GHS-R1a agonist engineered for oral GI stability, unlike peptide-class secretagogues that require injection. Oral GH-elevating efficacy was first demonstrated in dogs at 0.125 mg/kg (Patchett 1995, PNAS) and replicated across human oral RCTs at 2–25 mg once daily. [Verification: the frequently-repeated ~60–70% oral bioavailability and ~4–6 h elimination half-life (with IGF-1 elevation persisting ~24 h post single dose) are secondary/tertiary figures — the half-life traces only to a 2000 monograph 'in beagles' and the 60–70% figure to vendor/SEO blogs; neither is a primary peer-reviewed PK measurement. Treat as unverified, not settled fact.]

Every completed human trial identified administered MK-677 orally (capsule or oral solution); no published human study of a parenteral or intranasal/topical route was found. No human dosing protocol is implied — figures describe study design (species, dose range studied, trial duration), never a regimen to follow.

Animal & human figures are kept visibly separate so studied animal doses are never misread as human guidance.

Sorted A–Z by vendor — never by price

Weekly median $/mg from the live vendor crawl.

Researched storefront prices, bucketed

p25 $0.064 · median $0.088 · p75 $0.120 · 11 researched vendors

Legit, COA-backed band: $0.060–$0.230/mg.

Value rule: don't just buy the cheapest — a price under $3/mg is a red flag. Pair price with COA and independent-test grade.

Estimated cost of research (10 mg)

Vial (best researched price)

$1

Bacteriostatic water (generic estimate)

$6

Syringes / supplies (generic estimate)

$12

What each test proves — general guidance, plus this compound's researched purity data

Purity on the current market (researched)

Vendor-claimed HPLC purity for MK-677 research-market products commonly clusters ~98–99.9% (e.g. Sports Technology Labs advertises 99.87% via MZ Biolabs testing; buyer guides set the benchmark at '99% or higher'). No independent multi-vendor purity/quantity aggregate specific to MK-677 (a Finnrick/Janoshik-style investigation like the one behind the BPC-157 overlay) was located — MK-677 is a non-peptide small molecule and sits outside Finnrick's peptide-focused panel. The independent findings that DO exist point to adulteration/substitution risk rather than a purity distribution (see the 2026 TGA metandienone-substitution finding and the 2017 JAMA SARM-substitution analysis in events).

Independent labs cited for this compound

One relevant recall found: Agebox Inc. voluntarily recalled 'iKids-Growth' Day and Night Formula children's growth supplements (initiated Oct 28, 2025; recall Nos. D-0344-2026 / D-0345-2026, Class II; FDA warning letter followed Dec 19, 2025) after FDA lab testing found undeclared ibutamoren mesylate (MK-677) in both products — a dietary-supplement adulteration case, not a recall of a product sold AS an MK-677 research chemical. No recall of a labeled MK-677 research-market product itself was found this pass.

Buyer red-flag checklist

• No batch-specific Certificate of Analysis (COA) provided on request.
• COA is generic/undated, unverifiable, or run in-house rather than by a named independent lab.
• Unusually low price relative to the market — a documented pattern preceding underdosed/counterfeit research-chemical sales.
• Physical product shows clumping, discoloration, or a non-crystalline texture inconsistent with the labeled compound.
• Product sold as 'MK-677' with no felt response at the labeled amount — a reported signal of a mislabeled or substituted product (see the TGA metandienone-substitution finding and the 2017 JAMA SARM-substitution study).
• Purity-only COA with no mass-spectrometry identity confirmation (can't rule out wrong-compound substitution).
• Human-dosing / benefit marketing on a 'research use only' site — the pattern underlying the FDA's 2022, 2023 and 2025 warning letters.

GMP vs research-grade: the chemistry (SPPS + HPLC + MS) is identical — the difference is the quality system.

Underdosing / mislabeling: No independent lab aggregate (Janoshik/MZ Biolabs/Finnrick-style) quantifying MK-677 mg-fill accuracy across vendors was found this pass, so no prevalence figure is reported rather than estimated. The closest independent data point is category-level, not MK-677-specific: Van Wagoner et al. 2017 (JAMA) found only 41% (18/44) of online SARM-labeled products had an active-ingredient amount matching the label, with ibutamoren among the undeclared substances substituted into 17/44 (39%) of products.

• An RUO label is not an import exemption — CBP judges actual intended use.
• Lyophilized powder is ambient-stable in transit; temperature control needed for > 7-day transit.
• US-warehouse vendors dodge import scrutiny — they cost more but ship more reliably.

Every item dated & sourced

Prohibited at all times (in- and out-of-competition) under the WADA 2026 Prohibited List, class S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics), subsection S2.2.4 'Growth Hormone Releasing Factors' — the GHS/mimetics subsection, which names ibutamoren (MK-677) by example alongside anamorelin, capromorelin, ipamorelin, macimorelin and lenomorelin (ghrelin). No approved human therapeutic use, so no Therapeutic Use Exemption pathway. Also listed on the U.S. DoD Prohibited Dietary Supplement Ingredients List. [Verification: the exact S2.2.4 sub-code is sourced to the WADA List itself; OPSS corroborates the general prohibition but does not carry the sub-code.]

No granted patents identified in current seed. Composition-of-matter coverage is limited given the peptide's synthetic origin.

• IACUC / IRB research context
• RUO buyer responsibilities & documentation
• Veterinary / alternative-use where lawful
• Jurisdiction-aware "who may lawfully obtain"

What people discuss

Reported concerns — discussion, not established effects

Reading caveats

• Vendor-affiliated 'buying guide' and product blogs writing the appetite/sleep/purity narrative also sell the product — positivity-incentivized.
• Aggregator articles recycle a small number of the same Reddit anecdotes, inflating apparent independent-report volume; a raw Reddit thread URL could not be retrieved this pass.
• Bodybuilding/SARM-forum context frequently stacks MK-677 with testosterone/SARMs, confounding attribution of reported sleep, gains and hormonal effects to MK-677 alone.
• The one detailed hormonal-effects case report (gynecomastia/hypogonadism) involved products later found to contain undisclosed testosterone, estradiol and GH alongside MK-677, RAD-140 and cardarine — effects cannot be isolated to MK-677.
• Regulatory/gov safety coverage (DEA, TGA) is more recent and cautionary than the longer-running biohacking-forum sentiment, which skews positive on subjective sleep/recovery/appetite effects.
• Discussion concentrates in performance-enhancement forums (AnabolicMinds, iSARMS, steroid forums) rather than general Reddit — the sample may skew toward a PED audience rather than the broader research-peptide community.

Manually researched from reddit, youtube— theme weights are research estimates, not live counts; aggregated & de-identified. No individual posts, quotes, or usernames are ever shown.

Relative research / market volume — populated once the activity stream is wired

Inline tooltips for lyophilized, RUO, EU/mg, SPPS, 503A and more.

Toggle plain-language ↔ scientific in the header.

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• Understanding evidence grades

Oral non-peptide GHS-R1a agonist (spiropiperidine) that sustains pulsatile GH and IGF-1 elevation via ghrelin-receptor activation. Research use only. Approximately 40 articles are indexed (literature last scanned 2026-05-29). US regulatory status: Not FDA-approved; ibutamoren mesylate remains listed in active FDA 503A Category 2 (bulk drug substances that may present significant safety risks); PCAC voted against adding it to the 503A Bulks List; no compounding pathway. Research use only.

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