Peptides / Growth hormone axis

Small molecule · 528.7 Da

MK-677 (ibutamoren)

Not approvedBanned in sport

MK-677 (ibutamoren) is an oral compound, not a peptide, that acts on the ghrelin receptor and raises growth hormone and IGF-1 in studies. It is not approved, it has only an EU orphan designation, and it is banned in sport. PepBank shows 208 results on MK-677 from 23 studies in people, and 203 from animal and lab studies. The strongest evidence is a randomized trial in people. Data as of 2026-10-30.

Also known as L-163,191, LUM-201, MK-0677, MK-677, MK677, Ibutamoren mesilate and 5 more

Small molecule, shown without its saltPubChem 178024

Evidence level: Large trials in people208 of 411 results come from studies in people, including randomized trials.

Results in people

208

51% of 411 results

Results in animals

119

29% of 411 results

Results in lab cells

20% of 411 results

From computer models

0% of 411 results

Overview

MK-677 (ibutamoren) at a glance

What it is	Small molecule
Approval	Not approved for any use
In sport	Banned in sport (WADA S2.2.4)
Studies	90 studies with results. 68 of them gave MK-677, with 411 results. 208 in people119 in animals84 in lab cells
Best study in people	Randomized controlled trial with 123 people (2011)
Clinical trials	14 registered: 5 active or planned, 4 with posted results
Community use	Raising growth hormone and IGF-1 by mouth, without injections; Lean mass and bulking, often in a stack with SARMs or steroids; Deeper sleep and recovery; Appetite increase for people who struggle to eat enough

The science

What is MK-677?

Oral small molecule that activates the ghrelin receptor and raises growth hormone and IGF-1. Merck made it in the 1990s. FDA and EMA have not approved it as a medicine. As LUM-201 it is in a phase 3 trial in children with growth hormone deficiency that started on 2026-05-20.

411

Study results in PepBank

The history of MK-677

1995
The oldest paper on MK-677 in PepBank is from 1995.
1998July
A registered trial of MK-677 started (NCT00474279).

MK-677 (ibutamoren) structure and chemistry

The key facts about the molecule. Long codes are in the closed section below.

Structure

MK-677 (ibutamoren) is a small molecule, not a peptide chain.

Formula

C₂₇H₃₆N₄O₅S

Molecular weight

528.7 g/mol

CAS number

159634-47-6

Target

Growth hormone secretagogue receptor type 1 (ghrelin receptor) (gene GHSR): agonistEvidence: primary literature

Development

Lumos Pharma (Austin, Texas) develops it as LUM-201. Double Point Ventures has owned Lumos Pharma since 2024-12-12. Merck (Merck Sharp & Dohme) discovered it as MK-0677 and licensed it to Ammonett Pharma on 2013-10-22. Lumos bought LUM-201 from Ammonett in July 2018 (Lumos 10-Q). Highest phase: phase 3.

Identifiers

PubChem 178024, ChEMBL CHEMBL13817, UNII GJ0EGN38UL, KEGG D04491, IUPHAR 5867, PDB 7NA8

SMILES and InChIKey

InChIKey
UMUPQWIGCOZEOY-JOCHJYFZSA-N

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

See charge, composition and 3D structure on the Scientific page

The evidence

What MK-677 studies show

Results grouped by what the studies measured. Each card shows where its results come from.

Large trials in people208 of 411 results come from studies in people, including randomized trials.

Growth hormone and growth

130 results · 78 in people · 49 animal · 3 lab

In elderly hip fracture patients, MK-0677 increased IGF-1 compared with placebo. Archives of gerontology and geriatrics, 2011

Top results

In elderly hip fracture patients, MK-0677 increased IGF-1 compared with placebo. (Archives of gerontology and geriatrics, 2011)
In rats, oral MK‑677 did not increase body growth during 6 weeks. (Yonsei medical journal, 2018)
In hemodialysis patients, MK-0677 increased IGF-1 compared with its pretreatment level. (Nephrology, dialysis, transplantation, 2018)

Hormones

40 results · 22 in people · 15 animal · 3 lab

In obese males, MK‑677 did not increase serum cortisol compared with placebo. The Journal of clinical endocrinology and metabolism, 1998

Top results

In obese males, MK‑677 did not increase serum cortisol compared with placebo. (The Journal of clinical endocrinology and metabolism, 1998)
In obese men, MK‑677 increased free T3 more than placebo at 8 weeks. (Clinical endocrinology, 1999)
In calorically restricted volunteers, prolactin response was not significantly greater with MK‑677 than placebo. (The Journal of clinical endocrinology and metabolism, 1998)

Bones and joints

22 results · 22 in people

In functionally impaired elderly adults, MK‑677 increased osteocalcin more than placebo. Journal of bone and mineral research, 1999

Top results

In functionally impaired elderly adults, MK‑677 increased osteocalcin more than placebo. (Journal of bone and mineral research, 1999)
In obese males, MK‑677 increased a type I procollagen formation marker compared with placebo. (Journal of bone and mineral research, 1998)
In healthy older adults, bone density changes during MK‑677 treatment were consistent with increased bone remodeling. (Annals of internal medicine, 2008)

Cholesterol and blood fats

21 results · 19 in people · 2 lab

In healthy older adults, total cholesterol did not differ between MK‑677 and placebo. Annals of internal medicine, 2008

Top results

In healthy older adults, total cholesterol did not differ between MK‑677 and placebo. (Annals of internal medicine, 2008)
In obese men, MK‑677 did not significantly change lipoprotein(a) compared with placebo. (The Journal of clinical endocrinology and metabolism, 1999)
In healthy older adults, HDL cholesterol did not differ between MK‑677 and placebo. (Annals of internal medicine, 2008)

Weight and appetite

21 results · 14 in people · 7 animal

In healthy older adults, fat-free mass increased with MK‑677 and decreased with placebo. Annals of internal medicine, 2008

Top results

In healthy older adults, fat-free mass increased with MK‑677 and decreased with placebo. (Annals of internal medicine, 2008)
In obese men, MK‑677 increased serum leptin more than placebo at 2 weeks. (Clinical endocrinology, 1999)
In healthy older adults, body weight increased more with MK‑677 than placebo. (Annals of internal medicine, 2008)

Blood sugar

13 results · 11 in people · 2 animal

In obese males, fasting glucose was unchanged during MK‑677 treatment. The Journal of clinical endocrinology and metabolism, 1998

Top results

In obese males, fasting glucose was unchanged during MK‑677 treatment. (The Journal of clinical endocrinology and metabolism, 1998)
In dogs, insulin was higher after MK-0677 but remained within the normal range. (Endocrinology, 1996)
In healthy older adults, fasting glucose increased during MK‑677 treatment. (Annals of internal medicine, 2008)

All 90 MK-677 studies by area Open the Scientific page

Key MK-677 studies

Studies in people come first, then studies in animals and in the lab.

People
MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled phase IIb study
Adunsky et al. 2011 · Archives of gerontology and geriatrics · 123 people · cited by 48
7 results
People
Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial
Nass et al. 2008 · Annals of internal medicine · 65 people · cited by 176
21 results
People
Oral ghrelin receptor agonist MK-0677 increases serum insulin-like growth factor 1 in hemodialysis patients: a randomized blinded study
Campbell et al. 2018 · Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association · 22 people · cited by 17
3 results
People
Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial
Sevigny et al. 2008 · Neurology · 416 people · cited by 73
6 results
People
The effects of MK-0677, an oral growth hormone secretagogue, in patients with hip fracture
Bach et al. 2004 · Journal of the American Geriatrics Society · 161 people · cited by 58
6 results

All 90 MK-677 (ibutamoren) studies

MK-677 clinical trials

ClinicalTrials.gov lists 14 trials of MK-677. 5 are active or planned, and 4 have posted results. PepBank does not show trial results.

Solid bars are dates that happened. Hatched bars are planned dates. Data from ClinicalTrials.gov.

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

Phase 3recruiting150 planned

Phase 3 Long Term Safety Extension Study of LUM-201 in Children With Growth Hormone Deficiency

Phase 3not yet recruiting150 planned

Phase 2 Study of LUM-201 in Children With Growth Hormone Deficiency (OraGrowtH210 Trial)

Phase 2completed104 people

All 7 MK-677 (ibutamoren) trials

Status and safety

Is MK-677 approved?

FDA

United States

Not approved

No approved medicine contains it.

EMA

European Union

Not approved

No approved medicine contains it.

WADA

Sport

Banned

On the 2026 Prohibited List, section S2.2.4.

No. Not approved for any use. Its most advanced trial is in phase 3. The FDA, the EMA and the other sources we use show no approval (as of 22 Oct 2026). Banned in sport (WADA S2.2.4).

Laws and labels change, so check the regulator for the current status.

MK-677 side effects and safety

PepBank has 14 safety results from studies of MK-677. 12 of them come from studies in people.

Safety results from studies (14)

In elderly hip fracture patients, the MK-0677 group had fewer falls than placebo. The abstract does not call this significant (p = 0.096). (Archives of gerontology and geriatrics, 2011)
In hemodialysis patients, the study reported no serious adverse effects attributable to MK-0677. (Nephrology, dialysis, transplantation, 2018)
In calorically restricted volunteers, MK‑677 was generally well tolerated without clinically significant adverse experiences. (The Journal of clinical endocrinology and metabolism, 1998)
In healthy older adults, MK‑677 treatment was reported without serious adverse effects. (Annals of internal medicine, 2008)
In growth hormone-deficient men, MK‑677 was generally well tolerated. (The Journal of clinical endocrinology and metabolism, 1997)
A previously healthy man developed elevated liver enzymes after taking MK‑677 for 2 months. His liver tests normalized after he stopped MK‑677. (BMJ case reports, 2025)
In elderly hip fracture patients, fewer MK-0677 recipients fell than placebo recipients, but the difference was not statistically significant. (Archives of gerontology and geriatrics, 2011)
In healthy older adults, fasting glucose increased during MK‑677 treatment. (Annals of internal medicine, 2008)
In healthy older adults, increased appetite was a frequent MK‑677 side effect that subsided within a few months. (Annals of internal medicine, 2008)
In healthy older adults, temporary mild leg swelling was a frequent MK‑677 side effect. (Annals of internal medicine, 2008)
In healthy older adults, muscle pain was a frequent MK‑677 side effect. (Annals of internal medicine, 2008)
In elderly hip fracture patients, the MK-0677 trial ended early because of a heart failure safety signal. (Archives of gerontology and geriatrics, 2011)
In mice with an Alzheimer's disease model, MK0677 at 3 mg/kg increased deaths. (Journal of Alzheimer's disease, 2019)
In cells, ibutamoren's half-maximal toxic concentration was 42.4 μM. (BMB reports, 2020)

See every safety result on the Scientific page

Doses studied (40 shown)

The doses that these studies used. They are not recommendations.

Dose as reported	Class	Species	Route	Duration	Design	Source
25mg/day	Human	human	Not reported	24 weeks	Randomized trial in people · n = 123	Adunsky 2011
25 mg once daily	Human	human	oral	1 year	Randomized trial in people · n = 65	Nass 2008
25 mg daily	Human	human	Not reported	12 months	Randomized trial in people · n = 416	Sevigny 2008
5, 10, or 25 mg daily for 2 weeks followed by 25 mg daily for 7 weeks	Human	human	oral	9 weeks	Randomized trial in people · n = 91	Murphy 1999
25 mg daily for 2 weeks followed by 50 mg daily for 2 weeks	Human	human	oral	4 weeks	Randomized trial in people · n = 50	Murphy 1999
25 mg daily	Human	human	oral	8 weeks	Randomized trial in people · n = 24	Svensson 1998
25 mg/day	Human	human	oral	8 weeks	Randomized trial in people · n = 24	Svensson 1998
25 mg daily	Human	human	oral	8 weeks	Randomized trial in people · n = 24	Svensson 1999
25 mg/day	Human	human	oral	8 weeks	Randomized trial in people · n = 24	Svensson 1999
5 and 25 mg	Human	human	oral	7 days	Randomized trial in people · n = 9	Copinschi 1996
25 mg	Human	human	oral	7 days	Randomized trial in people · n = 9	Copinschi 1996
25 mg once daily	Human	human	oral	7 days	Randomized trial in people · n = 8	Murphy 1998
25 mg	Human	human	oral	7 days	Randomized trial in people · n = 8	Copinschi 1997
2, 10 or 25 mg/day	Human	human	oral	2 weeks	Randomized trial in people	Chapman 1996
25 mg/day	Human	human	oral	2 weeks	Randomized trial in people	Chapman 1996
25 mg daily	Human	human	oral	12 months	Randomized trial in people	Murphy 2001
10 mg	Human	human	oral	2 weeks	Randomized trial in people	Murphy 1999
25 mg	Human	human	oral	2 weeks	Randomized trial in people	Murphy 1999
10 mg or 25 mg for 2 weeks; 25 mg daily for 2 weeks followed by 50 mg daily for 2 weeks	Human	human	oral	2 weeks and 4 weeks	Randomized trial in people	Murphy 1999
0.8 mg/kg single dose	Human	human	oral	single dose	Trial in people without random groups · n = 68	Bright 2021
25mg daily	Human	human	oral	8 weeks	Trial in people without random groups · n = 12	Svensson 2003
10 or 50 mg once daily	Human	human	oral	4 days	Trial in people without random groups · n = 9	Chapman 1997
10 mg/day	Human	human	oral	4 days	Trial in people without random groups · n = 9	Chapman 1997
50 mg/day	Human	human	oral	4 days	Trial in people without random groups · n = 5	Chapman 1997
0.8 mg/kg per day	Human	human	oral	8 days	Trial in people without random groups	Codner 2001
10 mg single dose	Human	human	Not reported	single exposure	Reports of single patients · n = 1	Kintz 2026
60 capsules of 10 mg over 90 days	Human	human	Not reported	90 days	Reports of single patients · n = 1	Kintz 2026
0.25 mg/kg	Animal	dog	oral	Not reported	Study in live animals · n = 8	Jacks 1996
0.50 mg/kg	Animal	dog	oral	Not reported	Study in live animals · n = 8	Jacks 1996
1.0 mg/kg	Animal	dog	oral	Not reported	Study in live animals · n = 8	Jacks 1996
1 mg/kg	Animal	Dog	oral	Not reported	Study in live animals · n = 7	Schleim 1999
5 mg/kg/day	Animal	Dog	oral	15 days	Study in live animals · n = 4	Prahalada 1999
1 mg/kg	Animal	dog	oral	Not reported	Study in live animals · n = 3	Jacks 1996
as low as 0.125 mg/kg	Animal	dog	oral	Not reported	Study in live animals	Patchett 1995
1 mg/kg	Animal	dog	oral	Not reported	Study in live animals	Patchett 1995
1.0 mg/kg	Animal	dog	oral	Not reported	Study in live animals	Hickey 1997
0.5 mg/kg	Animal	dog	oral	Not reported	Study in live animals	Hickey 1997
0.25 mg/kg	Animal	dog	oral	Not reported	Study in live animals	Hickey 1997
3 mg/kg	Animal	mouse	Not reported	Not reported	Study in live animals	Tian 2019
4 mg/kg	Animal	rat	oral	Not reported	Study in live animals	Lee 2018

From the community

How people use it

What people report online. It comes from forums and guides, not from studies.

Community-reported. Not tested in trials.

Community sources describe MK-677 as an oral capsule or liquid that people take once a day, most often 10 to 25 mg, for 8 to 16 weeks. Some run it for months or about a year. Sources disagree on timing: some take it before bed for sleep, others take it in the morning to avoid daytime tiredness. The effects they report most are strong hunger, water retention, tiredness, numb or tingling hands, deeper sleep and higher blood glucose. It is not an approved medicine, and FDA has warned about it.

Reported routines and cautions

What people use it for

Raising growth hormone and IGF-1 by mouth, without injectionsS1S2S3
Lean mass and bulking, often in a stack with SARMs or steroidsS1S2S3S11 S13
Deeper sleep and recoveryS1S2S3S11
Appetite increase for people who struggle to eat enoughS2S8S10

Reported regimens

Regimens that community sources report for MK-677 (ibutamoren). Community-reported, not tested in trials.
Context	Route	Amount	How often	How long	Agreement	Sources
General use for growth hormone and IGF-1 and muscle gain: the 25 mg daily dose	oralcapsule, tablet or liquid	25 mg per dose	once daily	8 to 16 weeks in the wiki; forum posters report from a few days to almost a year	sources agree on 25 mg once daily; durations differ (S1 8 to 16 weeks, S5 almost a year). S1 is a compiled page that lists Reddit among its own sources. S5, S6 and S7 are forum threads that carry seller or sponsor links.	S1S2S5S6S7S12
Lower dose: 10 to 15 mg daily, often as a starting dose or to limit side effects	oral	10 to 15 mg per dose	once daily	8 to 16 weeks; some run 3 to 6 months	sources agree on about 10 to 12.5 mg once daily as a lower dose, with a wider 5 to 15 mg range; durations differ. S2 is a guide page. S1, S5, S6 and S8 are a compiled page and forum threads that carry seller or sponsor links.	S1S2S5S6S8
Night dosing: taken before bed for sleep, or to sleep through the hunger	oral	10 to 25 mg per dose	once daily, before bed	8 to 16 weeks	sources agree that night dosing is common and that people choose it for sleep and to reduce daytime tiredness; they disagree on whether it is better than morning dosing (see R4). All forum threads here carry seller or sponsor links.	S1S2S3S4S8S9S10
Morning or early-day dosing: to use the hunger during the day and avoid tiredness	oral	25 mg per dose	once daily, in the morning or early in the day	Not stated	sources differ: S4 says most people notice less daytime tiredness with morning dosing and S8 posters advise the morning for appetite, while S3, S9 and S10 posters take or suggest bedtime. Several posters say the timing matters little. All forum threads here carry seller or sponsor links.	S4S8S9S10
Long runs of months up to about a year	oral	10 to 25 mg per dose	once daily	3 to 6 months (S1); almost a year (S5)	sources report long runs but give few amounts. S1 is a compiled page, S5 and S10 are single forum posts that carry seller or sponsor links. The Healthy Male page says the health effects of long-term use have not been investigated.	S1S5S10

Reported side effects

strong hunger, often most intense in the first weeksS1S2S3S8S10S11 S12
water retention: puffy face and hands, swollen feet, rapid scale weightS1S2S3S5S6S11 S12
water retention that forum posters say fades after about 4 to 6 weeksS4
daytime tiredness or morning grogginess; sources disagree on whether morning or bedtime dosing causes itS1S2S3S4S9S10
numb or tingling hands or arms, sometimes on wakingS1S2S7S12
higher blood glucose and lower insulin sensitivityS1S2 S11 S12
vivid dreams; for a minority, disrupted sleepS2S3
anxiety and muscle painS12
after stopping: weight loss, return of sleep problems and aching joints (one account)S11

Reported benefits (claims, not shown in trials)

deeper sleep, often noticed within the first weekS1S2S3S11
fuller muscles and gains in lean mass or body weightS1S2S3S11
faster recovery after trainingS3S11
higher IGF-1 on blood tests (one poster: 145 to 210 on 25 mg a day)S5

Cautions

FDA says ibutamoren mesylate poses significant safety risks because of the potential for congestive heart failure in certain patients. It cites a hip fracture trial that was stopped early over a possible heart failure signal.S15
FDA says ibutamoren is not approved and that its safety and efficacy have not been established. FDA also says products with ibutamoren cannot be sold as dietary supplements. Its lab found undeclared ibutamoren in a growth product sold for children.S14
Healthy Male (Australia) says the health effects of long-term use have not been investigated, that at least one trial was stopped early over heart failure concerns, and that many studies show diabetes-like effects.S12
One guide page lists type 2 diabetes, prediabetes, active cancer, heart failure and untreated sleep apnoea among the reasons not to use it.S2
Products sold online are not checked for dose or purity. A guide page says purity, dosing accuracy and even identity vary a lot between suppliers.S2 S11

Status notes

FDA: no approved ibutamoren product. FDA lists ibutamoren mesylate in category 2 (significant safety risks) of the 503A list (added 2023-09-29) and the 503B list (added 2022-12-29).S15
FDA warning letters of 2025-12-12 and 2025-12-19 say ibutamoren is excluded from the definition of a dietary supplement.S14 S19
EU: not authorised. An orphan designation for growth hormone deficiency (EU/3/17/1882, 2017-06-20) exists; EMA says an orphan designation is not a marketing authorisation.S18
A phase 3 trial of the same compound under the name LUM-201 (1.6 mg/kg/day by mouth, children with growth hormone deficiency, Lumos Pharma) started on 2026-05-20 and is recruiting. This is a trial dose, not a label dose, and it is not advice.S16
WADA: ibutamoren (MK-677) is named in S2.2.4 of the Prohibited List. It is prohibited at all times.S17

Community sources

S1Ibutamoren (MK-677) Community Protocols & Anecdotal Reportspeptideprotocolwiki.comcarries seller links, not linked
S2MK-677: Dosage, Half-Life & Reconstitution (peptide database page) (opens in a new tab)jackedforums.com
S3MK-677 (thread, 2015-02-25)longecity.orgcarries seller links, not linked
S4MK-677 Dosing Timing (thread, 2017-09-18)isarms.comcarries seller links, not linked
S5Mk-677 questions. (thread, 2020-06-10)isarms.comcarries seller links, not linked
S6MK-677 and water retention (thread, 2016-03-17)isarms.comcarries seller links, not linked
S7Mk677 numb hands already? (thread, 2020-04-25)evolutionary.orgcarries seller links, not linked
S8mk 677 dose (thread, 2026-05-26)elitefitness.comcarries seller links, not linked
S9MK 677 dose time? (thread, 2016-08-01)anabolicminds.comcarries seller links, not linked
S10Mk 677 (thread, 2018-12-11)anabolicminds.comcarries seller links, not linked
S11Men are risking their health to use the latest underground gym pills (first-person account, 2025-08-16) (opens in a new tab)metro.co.uk
S12What you need to know about MK-677 (Ibutamoren) (opens in a new tab)healthymale.org.au
S13Ibutamoren (opens in a new tab)en.wikipedia.org
S14Agebox Inc. warning letter 718252, 2025-12-19 (opens in a new tab)fda.gov
S15Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (opens in a new tab)fda.gov
S16OraGrowtH Phase 3 study of LUM-201 in children with growth hormone deficiency (NCT06948214) (opens in a new tab)clinicaltrials.gov
S17WADA 2026 Prohibited List (S2.2.4) (opens in a new tab)wada-ama.org
S19Musclepower Enterprise Ltd. (Monster King, GE Labs) warning letter 719339, 2025-12-12 (opens in a new tab)fda.gov
S18EU/3/17/1882 orphan designation for treatment of growth hormone deficiency (opens in a new tab)ema.europa.eu

Gaps

No approved label exists in the US, EU or Australia, so there is no label regimen. The only official dose found is the trial dose of 1.6 mg/kg/day in the Lumos phase 3 study, and it is not a label. No Reddit page was used, because Reddit cannot be fetched. Pages from anabolicsteroidforums.com and ironmagazineforums.com were read earlier, but both hosts refused the connection when the quotes were re-checked, so nothing from them is used. looksmax.org, eroids.com and professionalmuscle.com answered HTTP 403, and getsmartaboutdrugs.gov, listennotes.com and washingtonpost.com did not load, so none is used. No harm-reduction page with community amounts was found. The Healthy Male page and the FDA pages give effects and cautions but no amounts. Except for S2, every wiki and forum page here carries seller or sponsor links, so the amounts rest on one compiled page (S1) and single forum posts. S1 lists Reddit among its own sources. S3 has a sponsor and advert block. S9 lists a company representative among the posters. S8 and S7 signatures link to sellers. Amounts above 25 mg (for example 40 to 50 mg) appear in forum threads but could not be re-checked, so they are not recorded. No source gave an amount or timing for sublingual use, although one poster asks about it. Only S2 and S1 mention breaks between runs, and neither gives a length. No source gave a combined amount for stacks with SARMs, steroids or other secretagogues. Timing sources conflict (R3 and R4). Several posters say that timing matters little. Sources about the effects often describe one person. The numbers (for example IGF-1 145 to 210) come from single posts and are not trial results.

Questions and more

Ask a question about MK-677

The answer links to every study it uses.

What does the evidence say about MK-677?Is MK-677 tested in people?Compare with Hexarelin Compare with GHRP-6

Sources

Database: PepBank data for MK-677 (data version 308560)
Regulator: FDA status record
Regulator: EMA status record
Regulator: WADA status record
Trial registry: ClinicalTrials.gov
Community: community sources (forums and guides), as summarized in the PepBank community file

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

PepBank is a research reference. Talk to a doctor before you use any peptide.

Ask your AI about MK-677

Curo is a peptide shop. PepBank and Curo have the same owner. See the Curo catalog (opens in a new tab).

MK-677 (ibutamoren)

Not approvedBanned in sport

Also known as L-163,191, LUM-201, MK-0677, MK-677, MK677, Ibutamoren mesilate and 5 more

What it is

Small molecule

Approval

Not approved for any use

In sport

Banned in sport (WADA S2.2.4)

Studies

90 studies with results. 68 of them gave MK-677, with 411 results.
208 in people119 in animals84 in lab cells

Best study in people

Randomized controlled trial with 123 people (2011)

Clinical trials

14 registered: 5 active or planned, 4 with posted results

Community use

Raising growth hormone and IGF-1 by mouth, without injections; Lean mass and bulking, often in a stack with SARMs or steroids; Deeper sleep and recovery; Appetite increase for people who struggle to eat enough

Dose as reported

Class

Species

Route

Duration

Design

Source

25mg/day

Human

human

Not reported

24 weeks

Randomized trial in people · n = 123

Adunsky 2011

25 mg once daily

Human

human

oral

1 year

Randomized trial in people · n = 65

Nass 2008

25 mg daily

Human

human

Not reported

12 months

Randomized trial in people · n = 416

Sevigny 2008

5, 10, or 25 mg daily for 2 weeks followed by 25 mg daily for 7 weeks

Human

human

oral

9 weeks

Randomized trial in people · n = 91

Murphy 1999

25 mg daily for 2 weeks followed by 50 mg daily for 2 weeks

Human

human

oral

4 weeks

Randomized trial in people · n = 50

Murphy 1999

25 mg daily

Human

human

oral

8 weeks

Randomized trial in people · n = 24

Svensson 1998

25 mg/day

Human

human

oral

8 weeks

Randomized trial in people · n = 24

Svensson 1998

25 mg daily

Human

human

oral

8 weeks

Randomized trial in people · n = 24

Svensson 1999

25 mg/day

Human

human

oral

8 weeks

Randomized trial in people · n = 24

Svensson 1999

5 and 25 mg

Human

human

oral

7 days

Randomized trial in people · n = 9

Copinschi 1996

25 mg

Human

human

oral

7 days

Randomized trial in people · n = 9

Copinschi 1996

25 mg once daily

Human

human

oral

7 days

Randomized trial in people · n = 8

Murphy 1998

25 mg

Human

human

oral

7 days

Randomized trial in people · n = 8

Copinschi 1997

2, 10 or 25 mg/day

Human

human

oral

2 weeks

Randomized trial in people

Chapman 1996

25 mg/day

Human

human

oral

2 weeks

Randomized trial in people

Chapman 1996

25 mg daily

Human

human

oral

12 months

Randomized trial in people

Murphy 2001

10 mg

Human

human

oral

2 weeks

Randomized trial in people

Murphy 1999

25 mg

Human

human

oral

2 weeks

Randomized trial in people

Murphy 1999

10 mg or 25 mg for 2 weeks; 25 mg daily for 2 weeks followed by 50 mg daily for 2 weeks

Human

human

oral

2 weeks and 4 weeks

Randomized trial in people

Murphy 1999

0.8 mg/kg single dose

Human

human

oral

single dose

Trial in people without random groups · n = 68

Bright 2021

25mg daily

Human

human

oral

8 weeks

Trial in people without random groups · n = 12

Svensson 2003

10 or 50 mg once daily

Human

human

oral

4 days

Trial in people without random groups · n = 9

Chapman 1997

10 mg/day

Human

human

oral

4 days

Trial in people without random groups · n = 9

Chapman 1997

50 mg/day

Human

human

oral

4 days

Trial in people without random groups · n = 5

Chapman 1997

0.8 mg/kg per day

Human

human

oral

8 days

Trial in people without random groups

Codner 2001

10 mg single dose

Human

human

Not reported

single exposure

Reports of single patients · n = 1

Kintz 2026

60 capsules of 10 mg over 90 days

Human

human

Not reported

90 days

Reports of single patients · n = 1

Kintz 2026

0.25 mg/kg

Animal

dog

oral

Not reported

Study in live animals · n = 8

Jacks 1996

0.50 mg/kg

Animal

dog

oral

Not reported

Study in live animals · n = 8

Jacks 1996

1.0 mg/kg

Animal

dog

oral

Not reported

Study in live animals · n = 8

Jacks 1996

1 mg/kg

Animal

Dog

oral

Not reported

Study in live animals · n = 7

Schleim 1999

5 mg/kg/day

Animal

Dog

oral

15 days

Study in live animals · n = 4

Prahalada 1999

1 mg/kg

Animal

dog

oral

Not reported

Study in live animals · n = 3

Jacks 1996

as low as 0.125 mg/kg

Animal

dog

oral

Not reported

Study in live animals

Patchett 1995

1 mg/kg

Animal

dog

oral

Not reported

Study in live animals

Patchett 1995

1.0 mg/kg

Animal

dog

oral

Not reported

Study in live animals

Hickey 1997

0.5 mg/kg

Animal

dog

oral

Not reported

Study in live animals

Hickey 1997

0.25 mg/kg

Animal

dog

oral

Not reported

Study in live animals

Hickey 1997

3 mg/kg

Animal

mouse

Not reported

Study in live animals

Tian 2019

4 mg/kg

Animal

rat

oral

Not reported

Study in live animals

Lee 2018

Context

Route

Amount

How often

How long

Agreement

Sources

General use for growth hormone and IGF-1 and muscle gain: the 25 mg daily dose

oralcapsule, tablet or liquid

25 mg per dose

once daily

8 to 16 weeks in the wiki; forum posters report from a few days to almost a year

sources agree on 25 mg once daily; durations differ (S1 8 to 16 weeks, S5 almost a year). S1 is a compiled page that lists Reddit among its own sources. S5, S6 and S7 are forum threads that carry seller or sponsor links.

S1S2S5S6S7S12

Lower dose: 10 to 15 mg daily, often as a starting dose or to limit side effects

oral

10 to 15 mg per dose

once daily

8 to 16 weeks; some run 3 to 6 months

sources agree on about 10 to 12.5 mg once daily as a lower dose, with a wider 5 to 15 mg range; durations differ. S2 is a guide page. S1, S5, S6 and S8 are a compiled page and forum threads that carry seller or sponsor links.

S1S2S5S6S8

Night dosing: taken before bed for sleep, or to sleep through the hunger

oral

10 to 25 mg per dose

once daily, before bed

8 to 16 weeks

sources agree that night dosing is common and that people choose it for sleep and to reduce daytime tiredness; they disagree on whether it is better than morning dosing (see R4). All forum threads here carry seller or sponsor links.

S1S2S3S4S8S9S10

Morning or early-day dosing: to use the hunger during the day and avoid tiredness

oral

25 mg per dose

once daily, in the morning or early in the day

Not stated

sources differ: S4 says most people notice less daytime tiredness with morning dosing and S8 posters advise the morning for appetite, while S3, S9 and S10 posters take or suggest bedtime. Several posters say the timing matters little. All forum threads here carry seller or sponsor links.

S4S8S9S10

Long runs of months up to about a year

oral

10 to 25 mg per dose

once daily

3 to 6 months (S1); almost a year (S5)

sources report long runs but give few amounts. S1 is a compiled page, S5 and S10 are single forum posts that carry seller or sponsor links. The Healthy Male page says the health effects of long-term use have not been investigated.

S1S5S10

MK-677 (ibutamoren)

MK-677 (ibutamoren) at a glance

What is MK-677?

The history of MK-677

MK-677 (ibutamoren) structure and chemistry

What MK-677 studies show

Growth hormone and growth

Hormones

Bones and joints

Cholesterol and blood fats

Weight and appetite

Blood sugar

Key MK-677 studies

MK-677 clinical trials

Is MK-677 approved?

MK-677 side effects and safety

How people use it

What people use it for

Reported regimens

Reported side effects

Reported benefits (claims, not shown in trials)

Cautions

Status notes

Community sources

Ask a question about MK-677

Related peptides

Sources

MK-677 (ibutamoren)

MK-677 (ibutamoren) at a glance

What is MK-677?

The history of MK-677

MK-677 (ibutamoren) structure and chemistry

What MK-677 studies show

Growth hormone and growth

Hormones

Bones and joints

Cholesterol and blood fats

Weight and appetite

Blood sugar

Key MK-677 studies

MK-677 clinical trials

Is MK-677 approved?

MK-677 side effects and safety

How people use it

What people use it for

Reported regimens

Reported side effects

Reported benefits (claims, not shown in trials)

Cautions

Status notes

Community sources

Ask a question about MK-677

Related peptides

Sources