MK-677 Headache: Can Ibutamoren Cause Headaches?

Can MK-677 cause headaches? Yes, sometimes: headache shows up in several MK-677 trials, usually as one or two cases per trial, and the FDA lists it among side effects reported in multiple studies. It was more common than on placebo in the largest trial, and a few participants stopped treatment over it. Possible causes include higher blood pressure and fluid retention, which MK-677 can cause, and ingredients that aren’t on the label. A sudden, severe or “worst ever” headache, or one with vision or speech changes, needs urgent medical care.

This page covers how often headaches happened in MK-677 studies, the likely reasons, and what the research and medical guidance say to do about them. For the compound itself, see our MK-677 (ibutamoren) review.

Does MK-677 cause headaches?

Here is every trial headache report we could find, from the FDA’s 2024 review of the published studies:

Sources: FDA 2024, which summarizes the side-effect data from each study. The FDA lists headache among the “common AEs that were reported in multiple studies”, alongside high blood sugar, raised liver enzymes, muscle complaints, fluid retention and increased appetite.

So the older version of this page was wrong to say MK-677 “does not cause headaches”. It is not one of the most frequent side effects, but it is a recorded one.

Water retention and blood pressure

MK-677 causes mild swelling in many users: 19 of 43 healthy older adults on 25 mg/day vs 6 of 22 on placebo (FDA 2024). In older adults recovering from hip fracture it also raised systolic blood pressure by 11.9 to 16.4 mmHg (Adunsky 2011). Approved growth hormone medicines carry warnings about fluid retention and about raised pressure inside the skull (intracranial hypertension), and the FDA says similar risks may apply to ibutamoren (FDA 2024). No study has tested whether these effects explain headaches on MK-677, but they are the plausible mechanisms. The older claim that water retention can only cause a headache “after close to a year” had no evidence behind it.

Why people experience headaches when taking MK-677

• A side effect of the drug itself: recorded in trials, as above.
• Blood pressure and fluid: see above.
• Other compounds in the stack: SARMs and other drugs taken alongside MK-677 have side effects of their own.
• Whatever else is in the product: see below.
• Everyday triggers: stress, fatigue, alcohol, too much caffeine or caffeine withdrawal, and eye strain are common tension-headache triggers with or without MK-677 (MedlinePlus).

Bunk MK-677

Products sold online often don’t contain what the label says. Of 44 products sold as SARMs, 25% contained substances not on the label, 9% contained no active compound, and only 41% matched the labeled amount (Van Wagoner 2017). In one case report, products labeled MK-677, RAD-140 and cardarine also contained testosterone, estradiol and growth hormone (Chong 2024). The FDA also received a report of a man taking a product labeled ibutamoren 25 mg who had headache, diarrhea, stomach discomfort and weight loss; the report was too thin to judge the cause (FDA 2024). Mislabeled products can explain unexpected side effects, though nobody has measured how often they cause headaches.

The original author’s experience

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

I have done multiple MK 677 cycles and I experienced no headaches during the cycles. I always made sure that I bought real, high-quality products and that I drank enough water.

How to avoid the MK-677 headache

No study has tested ways to prevent headaches on MK-677. What the evidence supports:

Know what you are taking

Mislabeled products are common (Van Wagoner 2017). A batch-specific certificate of analysis from an independent lab is the minimum check. Sarmguide’s current partner shop is SwissChems; see our SwissChems review.

Watch blood pressure and swelling

Trial investigators checked blood pressure and swelling at visits, and stopped treatment in some people for high blood pressure or fluid retention (FDA 2024). More on this in MK-677 and the heart.

Sleep, stress and caffeine

The everyday triggers still apply: stress, fatigue, alcohol and caffeine changes (MedlinePlus). Keeping them steady makes it easier to tell whether a new headache is linked to something you started taking.

When a headache is an emergency

Get urgent care if a headache is sudden and explosive, the “worst ever”, the first severe headache of your life, or comes with slurred speech, vision changes, weakness, confusion, fever with a stiff neck, or after a head injury. See a doctor soon if headaches last more than a few days, wake you from sleep or change in pattern (MedlinePlus). Tell the doctor about MK-677 and anything else you take.

Conclusion

MK-677 can cause headaches. They were uncommon in trials, but they were recorded in several studies, appeared more often than on placebo in the largest one, and led a few people to stop. Rising blood pressure, fluid retention and mislabeled products are the likely contributors. For the full picture, see MK-677 side effects.