MK-677 Morning or Night: When to Take Ibutamoren, According to the Studies

MK-677 morning or night? Human trials did both: the sleep studies gave it at bedtime, and the 12-month trial that measured muscle and body-composition changes gave it between 7 and 9 in the morning. No trial has compared morning with night dosing head to head, for results or for side effects. What the trials had in common is once-a-day dosing at a fixed time, because one dose raises growth hormone for about 24 hours.

Below: when each study gave MK-677, the pros and cons of each time according to the evidence, and the original author’s own routine. For doses, see MK-677 dosage; for the compound itself, our MK-677 (ibutamoren) review.

When did the studies give MK-677?

Most other trials reported once-daily dosing without a time in their abstracts. A single dose is described as “long-acting (24 hours)” (FDA 2024); no human plasma half-life has been published.

Morning pros and cons

Pros of morning dosing (evidence):

• It is how the longest body-composition trial gave MK-677: fat-free mass rose 1.1 kg vs a 0.5 kg loss on placebo over 12 months with 25 mg taken between 7 and 9 am (Nass 2008).
• GH and IGF-1 stayed raised all year with morning doses: GH 1.8-fold and IGF-1 1.5-fold (Nass 2008).

Cons of morning dosing (evidence):

• Increased appetite still affected most people: 67% vs 36% on placebo with morning dosing (Nass 2008). If you want more appetite to help you eat more, that is a pro; if not, a con.
• The sleep improvements were measured with bedtime doses, not morning doses (Copinschi 1997).

The original version of this page also listed lethargy as a con of morning dosing. That comes from user reports; tiredness has been reported in trials (FDA 2024), but no study has linked it to the time of day.

Night pros and cons

Pros of night (bedtime) dosing (evidence):

• It is how the sleep study gave MK-677: on 25 mg at bedtime, young adults had about 50% more stage IV (deep) sleep and over 20% more REM sleep than on placebo, and older adults nearly 50% more REM sleep (Copinschi 1997).
• Bedtime dosing raised IGF-1 with the dose and increased the number of GH pulses, and left 24-hour cortisol levels unchanged (Copinschi 1996). The sleep researchers point out that sleep and GH release share regulating mechanisms (Copinschi 1997).

Cons of night dosing (evidence):

• Bedtime dosing slightly shifted the timing of cortisol’s night-time low and morning rise, although total cortisol didn’t change (Copinschi 1996).
• The sleep study was small (14 people) and short (7 to 14 days); in the 12-month trial a sleep-quality questionnaire was part of a well-being score that did not differ from placebo (Nass 2008).

Does night dosing avoid the hunger? It is widely claimed, but no trial has measured appetite by time of day.

MK-677 morning or night – answer

Based on the trials:

• If the question is sleep: the only sleep data come from bedtime dosing (Copinschi 1997).
• If the question is body composition: the only long-term data come from morning dosing (Nass 2008).
• If the question is side effects: no study compared them by timing. Blood sugar, swelling and appetite effects were seen with morning dosing over 12 months (Nass 2008).

In every trial, MK-677 was taken once a day at a set time. No trial split the dose into two smaller doses. This is a summary of how the research was done, not a recommendation to take MK-677.

What the original author did

Editor’s note: this section is the original author’s personal routine from the earlier version of this page. It is one person’s experience, not evidence.

I also take MK 677, usually about 15 minutes before going to bed. Having tried both taking MK 677 dosages in the morning and before going to bed, I can definitely say that taking it before going to bed is better, at least for me.

I noticed a lot of differences between taking MK 677 in the morning or at night. The main thing is the increased sleep quality is a lot better if you take dosages before going to bed. Another thing that I noticed is that I experience no increased hunger if I take my dosages at night. If take MK 677 in the morning, I often get an obvious increase in hunger.

Conclusion

The MK-677 morning or night debate can’t be settled with data, because nobody has run the comparison. The sleep benefit was measured with bedtime doses, and the year-long body composition results came from morning doses. The side effects that matter most, higher blood sugar, swelling and more appetite, showed up regardless. More on those in MK-677 side effects, and more on sleep in the sleep section of our MK-677 review and our guide to peptides for sleep.