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MK-677 (Ibutamoren)

B

lead outcome

GH / IGF-1 elevation

grades vary by outcome ↓

Small molecule (non-peptide)⚠ WADA-banned

also called — MK-677 · MK-0677 · Ibutamoren (mesylate) · Merck code L-163,191 · pediatric development name LUM-201. INCI: none. Not a peptide and not a SARM (see below)

GH secretagogue (oral)body compositionslow-wave sleepappetite (research / gray-market)

Reference entry — not sold here. The oral, non-peptide sibling of the injectable GHRPs: same ghrelin-receptor mechanism, but a pill. Included because the demand is enormous and it sits right next to the GH-peptide cluster — honestly tagged as not a peptide. No dosing published here.

In brief

MK-677 (ibutamoren) is an oral, non-peptide ghrelin-receptor agonist — the pill version of the injectable GHRPs. Across ~30 years of trials it reliably raises GH and IGF-1 and deepens slow-wave sleep, and it modestly increases lean mass — but without improving strength or physical function, and at a real metabolic cost (insulin resistance / elevated blood glucose). It's not FDA-approved (the FDA is recalling consumer products that contain it), it carries a congestive-heart-failure safety signal from an elderly trial, and it's banned in sport. It is not a peptide and not a SARM.

Legal standing, by region

European Union

Not approved

not approved.

United States

Not approved

Not FDA-approved for any indication (30 years on, still unapproved; Merck shelved it, and Lumos's LUM-201 is in pediatric development, not approved). The FDA is actively enforcing against unapproved consumer products — a consumer alert on "iKids-Growth" (Sept 2025) and a recall of "Agebox" products containing undeclared ibutamoren (March 2026). It is not a scheduled substance, but selling it in supplements is unlawful.

⚠ WADA-prohibited in sportSport: WADA-prohibited at all times — Section S2 (GH secretagogues / ghrelin mimetics); directly detectable.

Evidence, by outcome

How we grade →

An honest grade per outcome — drawn from the evidence, not any catalogue. Hype and undemonstrated marketing claims grade low.

OutcomeEvidence base · effectGrade

GH / IGF-1 elevation

Well-established biomarker effect — which is not the same as a clinical benefit

~30 years of trials (Chapman 1996; Svensson 1998; many) · Sustained rise in GH & IGF-1

B

Slow-wave (deep) sleep

A genuine, often most-noticed effect

Documented across trials · Meaningful increase in stage-IV sleep

B

Fat-free (lean) mass

No strength or functional improvement — the key honest limit

Nass 2008 (Ann Intern Med, 2 yr, n=65): FFM +1.1 kg · Modest lean-mass gain

C

Anti-aging / physique / strength (the popular use)

The FFM gain ≠ performance; ghrelin-driven hunger causes fat gain in physique use

Lean-mass gain doesn't translate to function; appetite drives fat gain · Not demonstrated for these goals

F

Failed / halted indications

The congestive-heart-failure signal in elderly is a serious flag

Alzheimer's (Sevigny 2008 — no effect); hip-fracture trial (Adunsky 2011) terminated early on a CHF signal · Negative / safety-halted

—

Safety

Insulin resistance / elevated fasting glucose (primary risk); lower-extremity edema; appetite → fat gain; modest prolactin rise; theoretical oncogenic concern (sustained IGF-1); CHF signal; WADA-banned

Multiple trials · Real concerns

—

Disclosure

Vallydia sells its own cosmetic serums, and some ingredients graded here belong to the same categories as those products. Grades are drawn from the published evidence by the method we publish, and applied to our own ingredients on the same terms — our copper-peptide serum is graded no more kindly than the peptides it competes with. We disclose the interest so you can weigh it.

Trade names shown here (for example Matrixyl, Argireline, Syn-Ake) are the property of their respective owners and are used only to identify the ingredient under discussion. Their appearance implies no affiliation with, or endorsement by, the proprietor.

Evidence changes

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Identity

a non-peptide small molecule — a spiroindanylpiperidine (~529 Da), chemically closer to a conventional drug than to a peptide. Synthesised in 1995 by Arthur Patchett's team at Merck (Patchett, PNAS 1995; Smith, Science 1997) as an orally active growth-hormone secretagogue. It is a long-acting (elimination half-life ~24 hours, supporting once-daily use) agonist of the ghrelin receptor (GHS-R1a) — the same receptor as the injectable GHRPs (GHRP-6 #24, GHRP-2 #23, Ipamorelin #17, Hexarelin #21), but taken by mouth.

Mechanism (as proposed)

binds GHS-R1a (the ghrelin receptor) on hypothalamic and pituitary somatotrophs → pulsatile GH release (mimicking the body's natural overnight pattern) → hepatic IGF-1, which drives the downstream muscle/fat/bone/sleep effects. It also mimics ghrelin's appetite signal (relentless hunger). Its oral, small-molecule nature and long half-life are what distinguish it from the injectable GHRPs — as is its tendency to raise blood glucose with sustained use.

Chemical identifiers

Cross-reference identifiers for the authoritative external databases — not a recipe, and nothing about how to use it.

PubChem CID6450830

InChIKeyDUGMCDWNXXFHDE-VZYDHVRKSA-N

SMILESCC(C)(C(=O)N[C@H](COCC1=CC=CC=C1)C(=O)N2CCC3(CC2)CN(C4=CC=CC=C34)S(=O)(=O)C)N.CS(=O)(=O)O

UNIIR90JB6QJ2B

ChEMBLCHEMBL2105872

via PubChem exact-name match (MK-677) · high confidence

Sources — 5 cited

01Patchett AA, et al. (A nonpeptidyl growth hormone secretagogue.) PNAS. 1995; Smith RG, et al. Science. 1997.

02Chapman IM, et al. (Stimulation of the GH/IGF-1 axis by oral MK-677.) J Clin Endocrinol Metab. 1996.

03Nass R, et al. Effects of an oral ghrelin mimetic on body composition in healthy older adults. Ann Intern Med. 2008. (FFM +1.1 kg, no strength gain.)

04Sevigny JJ, et al. (MK-677 — no clinical effect on Alzheimer's progression.) Neurology. 2008; Adunsky A, et al. (Hip-fracture trial terminated on CHF signal.) 2011.

05Lumos Pharma — LUM-201 (OraGrowtH210/212) pediatric GHD Phase 2.

Updated 2026-07-10

Grades reflect the published evidence, not our interest. No dosing, reconstitution, or administration is published for research compounds — that restraint is deliberate.

Related compounds

GHRP-2 (Pralmorelin)B

Hexarelin (Examorelin)B

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This site provides neutral scientific reference and sells only products lawful in your region. Nothing here is medical advice, a recommendation, or an offer to supply unapproved medicines. No dosing or administration is published for research compounds. Cosmetic peptides per Regulation (EC) 1223/2009. Unapproved injectable peptides are neither sold nor advertised in the EU (Directive 2001/83/EC, Title VIII). © 2026 Vallydia.