MK-677 for muscle gains: what gym TikTok gets wrong

What did @liftsbyfahd actually say?

The creator documented a 30-day run of MK-677 at 15mg daily, gaining 15 pounds from 180 to 195 pounds. He openly attributed the weight gain to a mix of water retention, some fat, and "lean tissue," while eating in a caloric surplus. He also disclosed getting baseline bloodwork before moving to what he called an "animal compound" next.

To his credit, he did not claim the 15 pounds was muscle. He said plainly: "a lot of that is water weight, a lot of that is some fat." He acknowledged the trade-off, noting he lost visible ab definition. He also stated he is not promoting PED use, just documenting his own journey. That framing is worth noting, even if the line between documentation and promotion gets blurry at 97K views.

The teaser for an unnamed "animal compound" coming next is concerning territory, and we will address that separately.

Does the science back this up?

The weight gain and body composition pattern he described are consistent with what MK-677 (ibutamoren) actually does in the literature. This is not a compound with a lot of controversy about its short-term effects. The controversy is about whether those effects are worth anything long-term.

MK-677 is an orally active ghrelin mimetic and growth hormone secretagogue. It reliably raises GH and IGF-1 levels. Murphy et al. (1998, Journal of Clinical Endocrinology and Metabolism) showed significant IGF-1 increases and lean mass gains in healthy adults over two months, but also noted increased appetite and fluid retention as consistent side effects. Svensson et al. (1998, Journal of Clinical Endocrinology and Metabolism) found similar results with notable water retention. The 15-pound gain in 30 days on a caloric surplus with MK-677 is plausible. Most of that weight in four weeks being water and fat is also plausible, not a confession, just physiology.

What is less clear is how much the MK-677 actually drove the gain versus the simple caloric surplus. The compound increases appetite significantly, so the mechanism may partly be: MK-677 makes you hungry, you eat more, you gain weight. That is not the same as the drug directly building muscle.

What did they get wrong (or right)?

He got the water retention story right. That is genuinely what happens with MK-677, and he did not try to hide it or reframe it as muscle. Give him credit there.

What is missing is any acknowledgment of the relevant side effect profile beyond water retention. MK-677 has been associated with increased fasting glucose and insulin resistance, particularly with extended use. Smith et al. (2005, Journal of Clinical Endocrinology and Metabolism) found measurable increases in fasting blood glucose in older adults on ibutamoren. He mentioned getting bloodwork, which is good, but he did not tell his audience what to look for or why glucose and insulin sensitivity panels matter here.

His body fat estimates of 12 to 15 percent are unverifiable from the video and are the kind of visual guessing that fitness creators routinely get wrong by 3 to 5 percentage points. This is a minor issue but worth naming.

The "general consensus is that you use MK as a bulking agent" framing overstates community wisdom as settled science. MK-677 has not been approved by the FDA for any indication in healthy adults.

What should you actually know?

MK-677 is not approved by the FDA for use in healthy adults, and it is not a SARM despite frequent misclassification online. It is a ghrelin receptor agonist that stimulates GH release. The distinction matters because the regulatory and safety status differs from anabolic steroids and from approved medications.

The side effects that do not show up in a physique video include: increased appetite leading to fat gain on a surplus (he acknowledged this), potential insulin resistance with prolonged use, possible increases in prolactin, and water retention that can mask body composition changes entirely. For anyone with pre-existing metabolic concerns, this profile is not trivial.

• Bloodwork before starting is genuinely good practice, and he mentioned doing it. That is more than most creators doing similar content.
• The teaser about a coming "animal compound" is a red flag. Stacking unregulated compounds without medical supervision carries compounded risks that a single-compound bloodwork baseline does not adequately address.
• If you are considering any GH secretagogue, a conversation with a licensed provider who can monitor IGF-1, fasting glucose, and HbA1c is the minimum reasonable step, not a TikTok series.

The bottom line

This video is more honest than most MK-677 content on TikTok. He acknowledged water retention, fat gain, and appetite effects without dressing them up as muscle. He got bloodwork. He did not claim 15 pounds of muscle in 30 days. For the genre, that is relatively responsible. But the audience skews young, the context is a hype reel for a harder compound coming tomorrow, and the missing safety context about glucose metabolism and unregulated status is a real gap. Honest is better than dishonest. It is still not the same as safe or complete.