MK-677 Dosage: What Doses Human Trials Used

In human trials, adults took MK-677 by mouth once a day at doses from 2 mg to 50 mg. 25 mg/day was by far the most-studied dose and the one used in every adult trial that lasted about six months or longer. Children with growth hormone deficiency received 0.2 to 3.2 mg per kg of body weight. These were research doses given under medical supervision. No dose of MK-677 is approved, and no trial has set a safe dose for healthy people.

This page lists the doses every verified human trial used, what changed with the dose, how long the studies lasted, how liquid and capsule products are labeled, and what the evidence says about bulking, cutting and women. It reports history, not a protocol. For the compound itself, see our MK-677 (ibutamoren) review.

MK-677 doses used in human trials

The FDA’s 2024 review summed it up the same way: ibutamoren was tested at fixed doses from 2 to 50 mg per day or weight-based doses from 0.2 to 0.8 mg/kg/day, for up to two years (FDA 2024). The higher weight-based doses come from the later LUM-201 trial.

10 mg vs 25 mg vs 50 mg: what changed with the dose

Several trials compared doses side by side. The pattern: more drug meant more IGF-1, and the blood sugar effects showed up at the higher doses.

• 2, 10 and 25 mg (older adults, 2–4 weeks): GH rose with the dose. Only 25 mg/day brought IGF-1 into the young-adult range (141 to 265 µg/L), and the same dose raised fasting glucose from 5.4 to 6.8 mmol/L (Chapman 1996).
• 5 vs 25 mg (young men, 7 days): IGF-1 rose with the dose, and IGFBP-3 rose only on 25 mg (Copinschi 1996).
• 10 vs 50 mg (GH-deficient men, 4 days): IGF-1 rose 52% on 10 mg and 79% on 50 mg; insulin and after-meal glucose rose too (Chapman 1997).
• Sleep (young adults): the deep and REM sleep increases were reported for 25 mg, the higher of the two doses (Copinschi 1997).

Two claims you will see elsewhere are not supported. One is that 10 mg and 50 mg work about the same: in the trial that tested both, 50 mg raised IGF-1 more. The other is that doses above 25 mg give “diminishing returns”: no trial measured outcomes such as muscle or strength above 25 mg/day for longer than a few weeks.

Dose and side effects

Most side effects were recorded at 25 mg/day, because that is what the long trials used. In those trials, investigators lowered the dose when problems appeared:

• In a 9-week study, 6% of participants went from 25 to 10 mg because fasting glucose rose above 140 mg/dL, and three of them still had to stop (FDA 2024). See MK-677 and blood sugar.
• In the 12-month trial, four people were moved to 10 mg because of high glucose or joint pain (FDA 2024).
• Night sweats and a day of hand numbness were reported on 50 mg in GH-deficient men; headache, diarrhea and dry skin on 10 mg (FDA 2024).

The full list is on our MK-677 side effects page.

MK-677 cycle length: how long the studies lasted

Searches for “MK-677 cycle” are really asking how long people take it. In trials, the length ranged from 4 days to 2 years:

What happens over time and after stopping:

• In people, the effect held for a year: GH was still 1.8 times and IGF-1 1.5 times baseline at 12 months (Nass 2008).
• In rats, the GH response faded with continuous daily dosing over six weeks (FDA 2024).
• IGF-1 went back to baseline within about a month after people stopped (Nass 2008).
• Fasting glucose and HbA1c were still higher at 12 months; in the small group that stayed on MK-677 for a second year, fasting glucose was no longer significantly above baseline (Nass 2008).

No trial has tested on-and-off “cycling” of MK-677, so any fixed cycle length or break length you read online is opinion.

MK-677 half-life and once-daily dosing

Every trial gave MK-677 once a day. No human plasma half-life has been published: the FDA found no detailed human pharmacokinetic data, and quotes a 1997 paper saying a single dose is “long-acting (24 hours)” (FDA 2024). That 24 hours describes how long GH stays raised, not how fast the drug leaves the blood. Half-life figures such as “4–6 hours” on vendor sites are not backed by a published human study.

When studies gave it: morning or bedtime

The sleep studies gave MK-677 at bedtime (Copinschi 1996, Copinschi 1997). The 12-month body composition trial gave it between 7 and 9 am (Nass 2008). No trial compared the two. More in MK-677 morning or night.

Weight-based doses in children

The only trials of MK-677 in young people were in children with diagnosed GH deficiency, treated by specialists. They received 0.2 to 3.2 mg/kg/day, and the children in the later trials were first given a single test dose to see who responded (Bright 2021, NCT04614337). These are not doses for healthy teenagers; see MK-677 and height.

MK-677 dosage in mL: liquids, capsules and labels

MK-677 is sold as capsules, tablets and liquids. The trials used tablets taken by mouth (Nass 2008), and the products nominated to the FDA for compounding were 10 mg and 25 mg capsules or tablets (FDA 2024). No study has compared liquid with capsules in people.

A liquid’s label gives its strength in milligrams per milliliter (mg/mL). The amount of drug in any volume is the strength times the volume: a product labeled 25 mg/mL holds 25 mg in each full milliliter, and a product labeled 10 mg/mL holds 10 mg. Two products can look identical and differ several-fold, so the label strength matters more than the dropper.

The bigger problem is whether the label is right. Of 44 products sold online as SARMs, the amount found differed substantially from the label in 59%, and 9% contained no active compound at all (Van Wagoner 2017). European medicines labs found that some seized products were even overdosed (Barrios 2025). That uncertainty applies to any mL figure. If you compare products, look for a batch-specific certificate of analysis from an independent lab; our SwissChems review explains why it is our current partner shop.

Dosage for bulking, cutting, beginners and women: what the evidence covers

What the trials measured at these doses

Every long trial tracked IGF-1, fasting glucose, HbA1c and insulin, plus liver enzymes, prolactin, lipids, blood pressure and swelling (FDA 2024). Those are the places where dose-related problems showed up. The bloodwork section of our MK-677 review and the bloodwork planner explain each one.

What changed on this page

An older version of this page gave a personal dosing recommendation, a bulking cycle and a link to a shop we no longer feature, said MK-677’s half-life was “around five hours” and said 10 mg and 50 mg worked about the same. We have replaced those parts with what the studies actually used and found. See our editorial policy.