Research peptides

Does MK-677 Cause Hair Loss? What the Trials Show

Q: Does MK-677 cause hair loss?

Not established. I reviewed the four published human trials of MK-677 (ibutamoren) this site can verify, and none measured hair loss, thinning or shedding. So there is no trial evidence that MK-677 causes hair loss, and none ruling it out. The page also covers the reasoning people use to link the two and real user reports, both labelled as inference and anecdote.

MK-677 and hair loss: what four published human trials measured, the IGF-1/DHT reasoning people cite, and what users report.

Written bySebastian Hunter, Founder and EditorI'm a 42-year-old senior advisor and distance runner who came to peptides as a sceptic. I'm not a doctor: I read the research, run my own experiment and keep honest notes. Read full bio

Published September 27, 2026

The short version

No published human trial has measured hair loss, thinning or shedding on MK-677 (ibutamoren). The four trials this site can verify did not report hair as an outcome. People who link MK-677 to hair loss are reasoning from what the trials did measure. It raises IGF-1 and reduces insulin sensitivity, and a small cortisol rise is a recognised trigger of temporary shedding in general. None of that is a tested finding about MK-677 and hair. User reports online are mixed: some describe shedding, others no change or thicker hair.

No published human trial has measured hair loss, thinning or shedding on MK-677.
The IGF-1/DHT reasoning some people cite is an inference, not a tested finding.
One trial found a small cortisol rise, a general trigger of temporary shedding, but nobody has tied it to MK-677 and hair.
User reports online are mixed: shedding, no change and thicker hair are all reported.
DHT-driven hair miniaturization only affects people with inherited androgenetic sensitivity.

Short answer: not established. No published human trial of MK-677 (ibutamoren) has measured hair loss, thinning or shedding. This page covers what the trials did measure, the reasoning people use to link MK-677 to hair loss anyway, and what users report. Each is labelled as trial finding, inference or anecdote. For what MK-677 is and its legal status, see the main MK-677 page. For the full trial-by-trial side-effect record, see MK-677 side effects.

US legal status - Research use only

Sold for laboratory research use only. Not approved by the FDA for human use, and cannot be lawfully marketed as a supplement or a medicine. Products sold this way are not made to pharmaceutical quality standards, and their contents are not verified by anyone.

Does MK-677 cause hair loss?

No meaningful evidence

No published studies of adequate quality to draw on. Four published human trials of MK-677 exist in this site's verified registry, in older adults and obese men, 14 days to 2 years. None measured hair loss, hair thinning or hair shedding as an outcome, in either direction.

I searched the published literature for a human trial or case report linking MK-677 to hair loss, thinning or shedding, and found none. There is no published human evidence that MK-677 causes hair loss, and none ruling it out. Anyone claiming certainty either way is going beyond what has been studied.

What the four published trials measured

Trial	Population	Duration	What it measured (not hair)
Chapman et al. 1996 Chapman 1996 - Chapman IM, Bach MA, Van Cauter E et al. Stimulation 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. J Clin Endocrinol Metab. 1996;81(12):4249-57., in the references below	32 healthy adults, 64-81	14 + 28 days	GH, IGF-1, fasting glucose
Svensson et al. 1998 Svensson 1998 - Svensson J, Lönn L, Jansson JO et al. Two-month treatment of obese subjects with the oral growth hormone (GH) secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure. J Clin Endocrinol Metab. 1998;83(2):362-9., in the references below	24 obese men, 18-50	8 weeks	GH, oral glucose tolerance, fat-free mass
Svensson et al. 1999 Svensson 1999 - Svensson J, Carlsson B, Carlsson LM et al. Discrepancy between serum leptin values and total body fat in response to the oral growth hormone secretagogue MK-677. Clin Endocrinol (Oxf). 1999;50(4):451-6., in the references below	Same 24-subject cohort	8 weeks	Testosterone, leptin, body fat
Nass et al. 2008 Nass 2008 - Nass R, Pezzoli SS, Oliveri MC et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med. 2008;149(9):601-11., in the references below	65 healthy adults, 60-81	2 years	GH, IGF-1, fat-free mass, glucose, cortisol, edema

None of the four asked about, examined or photographed hair. A trial only reports what it set out to measure.

The IGF-1 and DHT reasoning

This is reasoning, not a finding

MK-677 reliably raises IGF-1 and fasting glucose Chapman 1996 - Chapman IM, Bach MA, Van Cauter E et al. Stimulation 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. J Clin Endocrinol Metab. 1996;81(12):4249-57., in the references below, and in the trial that measured it directly, reduced insulin sensitivity Nass 2008 - Nass R, Pezzoli SS, Oliveri MC et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med. 2008;149(9):601-11., in the references below. Some commentators reason from there. In general endocrinology discussion, raised IGF-1 and reduced insulin sensitivity are proposed to touch the same androgen pathways that produce DHT. DHT drives androgenetic (pattern) hair loss in genetically susceptible people. No published MK-677 trial measured DHT, testosterone-to-DHT conversion, or any hair outcome. This is an inference built from adjacent findings, not a conclusion any study has tested.

The 2-year trial also found a small cortisol rise on MK-677, 47 nmol/L above placebo Nass 2008 - Nass R, Pezzoli SS, Oliveri MC et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med. 2008;149(9):601-11., in the references below. Elevated cortisol is a recognised general trigger of telogen effluvium, a temporary, diffuse shedding pattern. That is a general mechanism, not a finding specific to MK-677. No study has tested whether the cortisol change in that trial was large or sustained enough to cause measurable shedding in anyone. The trial’s other findings are on MK-677 side effects.

What people report

Real user reports exist, and they disagree. A HairLossTalk forum thread on HGH/MK-677/ibutamoren and hair loss includes:

posters who noticed no change to their hair after extended use
one poster who proposes an insulin/DHT mechanism like the reasoning above
others who argue MK-677 has no hormonal effect on hair at all

More Plates More Dates’ MK-677 FAQ states that ibutamoren does not change testosterone, estrogen or DHT levels. It argues there is no androgenic pathway for it to cause lasting hair loss.

Both are user reports and independent commentary, not clinical evidence, and they point in different directions. Nobody, including this page, can say with confidence what MK-677 will do to your hair.

Who this might matter to

DHT-driven miniaturization, the mechanism behind most pattern hair loss, only affects follicles in people with an inherited sensitivity to it. If the IGF-1/DHT reasoning has any real effect, genetics would decide who it touches, as it decides who gets androgenetic alopecia at all. Nobody has tested that interaction directly.

If you notice shedding

This page cannot diagnose the cause of hair shedding. MK-677 is not the only possible explanation: rapid fat loss, diet changes, stress, illness, medication changes and genetics can all produce similar shedding. If shedding is sudden, diffuse, or continues past a few months, get it evaluated by a clinician or dermatologist. For the broader safety record, including the FDA heart-failure signal this compound carries, see the MK-677 side effects page.

Regulatory changes for this compound and others, as they happen: US peptide regulation tracker.

Common questions

What is the IGF-1/DHT theory about MK-677 and hair loss?

MK-677 reliably raises IGF-1 and fasting glucose, and the 2-year trial that measured it directly found reduced insulin sensitivity. Some commentators reason that both could influence the androgen pathways behind DHT-driven androgenetic alopecia. No published MK-677 trial measured DHT, testosterone-to-DHT conversion or any hair outcome. So this is an inference from adjacent findings, not a tested conclusion.

Do people report hair shedding on MK-677?

Reports online are mixed. A HairLossTalk forum thread includes posters who noticed no hair change, one who proposes an insulin/DHT mechanism, and others who report no hormonal effect on hair. A separate commentary site, More Plates More Dates, states in its MK-677 FAQ that ibutamoren does not change testosterone, estrogen or DHT levels. It argues there is no androgenic pathway for lasting hair loss. These are user reports and commentary, not clinical evidence.

Is hair loss from MK-677 permanent?

Not established either way, because no trial measured it. General dermatology treats DHT-driven miniaturization as progressive only in people with inherited androgenetic sensitivity, and cortisol-linked shedding (telogen effluvium) as typically temporary. Neither pattern has been tested in someone taking MK-677.

Should I stop MK-677 if I notice hair shedding?

That is a decision for you and a clinician who knows your history. If shedding is sudden, diffuse or alarming, or comes with other symptoms, get it evaluated rather than guessing. MK-677, an unrelated health change, stress, diet or genetics can all produce similar shedding.

References (6 sources)

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.