MK-677 bodybuilding claims: what the research actually shows

What did @leov1ncent actually say?

He took MK-677 in his first year of training, gained 7 kilograms in a month, and called most of it water weight. He flagged hunger, vivid dreams, better sleep, and serious knee pain as side effects. His conclusion: "it was fucking pointless, especially for someone in their first year of training." He also warned that MK "can spike your insulin" and that eating too many carbs on it is a bad idea. Crucially, he admitted he was monitoring blood glucose with a finger-prick device. He ended by telling beginners to just eat enough protein and train hard instead.

This is not a promotional video. He's not selling anything. He's describing a negative personal experience with reasonable candor, which already puts it above most MK-677 content on TikTok.

Does the science back this up?

Mostly yes, and on the specific points that matter most, he's closer to correct than the average bro-science post. MK-677 (ibutamoren) is a ghrelin receptor agonist that stimulates growth hormone and IGF-1 secretion. The water retention, insulin resistance signal, and hunger effects he describes are all documented in peer-reviewed literature.

A randomized controlled trial by Murphy et al. (1998, Journal of Clinical Endocrinology and Metabolism) found that MK-677 significantly increased GH and IGF-1 but also caused fluid retention and increased fasting glucose in some participants. A later study by Nass et al. (2008, Annals of Internal Medicine) confirmed GH pulse amplification but also noted glucose metabolism changes in older adults. The hunger effect is mechanistically expected: ghrelin is a hunger hormone, and MK-677 mimics it. His observation about vivid dreams and improved sleep also has support. Copinschi et al. (1997, Sleep) found MK-677 increased REM sleep and slow-wave sleep in healthy young adults.

What did they get wrong (or right)?

He got the broad strokes right. Where things get imprecise is the joint pain claim. He describes severe knee pain "like someone spinning a scooter" into his knees. Joint pain has been reported anecdotally with MK-677, often attributed to fluid accumulation around joints or rapid changes in GH/IGF-1 levels. However, clinical trial data on this specific effect is thin. It's plausible, especially if he had pre-existing knee issues, but he presents it as a direct MK-677 side effect with more certainty than the evidence supports.

He's also slightly imprecise on the insulin mechanism. MK-677 doesn't spike insulin directly. It elevates GH, which induces insulin resistance over time, meaning your cells respond less efficiently to insulin. That's different from acutely raising insulin. The practical warning is still valid, but the mechanism he describes is a bit off. Credit where it's due: the fact that he was self-monitoring blood glucose is genuinely responsible behavior that most people using unregulated compounds skip entirely.

What should you actually know?

MK-677 is not FDA-approved for bodybuilding, muscle gain, or any use outside of clinical research contexts. It has been studied for muscle wasting in older populations and GH deficiency, not for healthy people in their first year of lifting. The compound is legal to purchase as a research chemical in some jurisdictions but is not approved for human use as a supplement or therapeutic.

The water weight gain he experienced is consistent with how MK-677 works. It raises GH, which increases sodium and water retention. Interpreting that as muscle gain, which many beginners do, is a well-documented mistake. A study by Svensson et al. (1998, Journal of Clinical Endocrinology and Metabolism) noted that GH-related body composition changes take months to manifest and early weight gain is predominantly fluid.

• MK-677 does not directly build muscle in healthy, well-nourished young adults in the short term.
• Elevated GH can worsen insulin sensitivity, especially in carbohydrate-heavy diets.
• Sleep quality improvements are real and documented, but they don't justify the metabolic risks for a healthy beginner.
• His advice to beginners, eat enough protein and train hard, is genuinely correct and evidence-based.

The bottom line

This video is refreshingly honest for the category. He's not claiming MK-677 is dangerous for everyone, and he's not telling you to take it. He's describing his own negative experience with a compound that has real pharmacological effects and real risks. The insulin mechanism is slightly garbled, and the joint pain claim is under-evidenced, but the core message holds up: a beginner using MK-677 to shortcut early training gains is taking on metabolic risk for a benefit that nutrition and training can deliver without the downside.