MK-677

If you’re looking into MK-677, odds are you want the growth-hormone upside — deeper sleep, easier size, faster recovery — without teaching yourself to jab a needle every day, and you heard there’s a pill that gets you there. So here’s the straight version.

MK-677 (ibutamoren) is an oral growth-hormone secretagogue — a once-daily pill people run for deeper sleep, a bigger appetite, and fuller-looking muscles. Unlike almost everything else on the research market, it has real human randomized trials behind it, and they agree on the headline: it raises your growth hormone and IGF-1. The open question was never whether it moves those dials — it’s whether the moved dials become the muscle and function people are paying for. The price of admission is the same short list for nearly everyone: water retention, hunger that won’t quit, and often puffy or numb-tingly hands. It’s not FDA-approved. And despite the crowd it runs with, MK-677 isn’t a peptide — it’s a small molecule you swallow.

What people actually use MK-677 for — and what they report

Strip away the lab talk and MK-677 has one of the most consistent street reputations of anything in this reference. People run it oral, once a day, for four overlapping reasons: sleep, appetite (usually to eat through a bulk), recovery, and the general “growth-hormone benefits without the needles” pitch. What comes back is just as consistent — a real sleep effect and an easy few pounds on the scale, shadowed by bloat, hunger, and a handful of side effects visible enough that people quit over them. It’s one of the rare compounds where the honest letdowns are as well-documented as the wins, because you can see most of them in the mirror.

The wins people describe. Sleep is the standout — the single most-praised effect on r/Peptides and the lifting forums. The common report is falling asleep faster, dropping into deeper sleep, and waking up actually rested, sometimes inside the first few nights. Vivid, feature-length dreams come along for the ride; most people file those under “cool,” a few under “exhausting.” Appetite is next: MK-677 makes food sound good again, which is a gift mid-bulk and a curse mid-cut. Then the softer stuff — fuller-looking muscles inside a couple of weeks, quicker recovery between sessions, and enough skin, hair, and nail comments to count as a pattern.

The letdowns, and there are real ones. The near-universal complaint is water. People describe a puffy face, a bloated midsection you can slosh a wave across, ankles that pit when you press them, and a scale that jumps four or five pounds in a week with nothing to do with muscle. The word that keeps recurring on the forums is looking like a “pufferfish,” and it’s a real reason people bail — the usual report is that the bloat settles after three or four weeks, but plenty decide a month of looking soft isn’t worth it. Right behind the water: the hunger can tip from “helpful” into “all I think about,” which is exactly why so many people can’t run it on a cut. A subset get carpal-tunnel-style numb or tingling hands, often worst overnight — that’s the fluid pressing on the nerves, and the community’s own fix is to drop the dose or cycle it, not push through. And early on, a lot of people report a stretch of lethargy or morning grogginess; the endless “morning or night?” argument is really just people trying to park that fog somewhere it doesn’t wreck their day.

The doses people actually run (anecdotal — not a validated protocol, and not what the trials tested): the common range is 10–25 mg a day by mouth, with 10–20 mg the spot most people settle at and 25 mg where the aches, joint stiffness, and lethargy get louder. Beginners usually open around 10–12.5 mg. Most dose once daily and run it for months rather than weeks, since the sleep and IGF-1 effects build and there’s no short half-life forcing a split. Timing is the forever debate: at night to ride the sleep and sleep through the hunger, or in the morning if the nighttime dose leaves them groggy — and some cycle five days on, two off, specifically to keep the numb-hands thing at bay. None of these numbers come from a trial; they’re crowd conventions handed lifter to lifter, and they carry exactly that much authority.

One honest asterisk over all of it: MK-677’s side effects are easy to see, and its main benefit isn’t. A “gained 12 pounds” log almost never separates the water and the extra food from actual muscle — the scale is the easiest thing to photograph and the least meaningful number in the picture. So read the glowing bulk logs as “the scale moved and I slept great,” which is true and worth something, and hold “it built me real muscle” to a much higher bar than a heavier, softer version of the same guy.

What is MK-677, exactly?

MK-677 is a lab-made small molecule — formula C27H36N4O5S, molecular weight about 528.7 g/mol, CAS 159634-47-6 — that most people know by its research name, ibutamoren. Here’s the label that matters most and gets missed constantly: MK-677 is not a peptide. Nearly everything else on this site’s recovery-and-growth shelf is a short chain of amino acids your gut would digest, which is why those get injected. MK-677 is a stable spiro-indoline compound that shrugs off digestion, so it works as a plain oral pill or dropper liquid once a day. Merck built it in the 1990s (as MK-0677) to raise growth hormone by mouth instead of by needle. Today, in the US, it’s sold only as a research chemical — and the very same molecule is being run through formal drug trials under the name LUM-201.

How does MK-677 work?

MK-677 works by imitating ghrelin, the hormone your stomach puts out when it’s empty. Ghrelin has two jobs that sound unrelated but ride the same wire: it makes you hungry, and it tells your pituitary to release a pulse of growth hormone. That’s the whole reason MK-677’s best feature (sleep, GH) and its biggest nuisance (hunger) arrive together — they’re the same button.

The plain-life version: ghrelin is a doorbell that tells the pituitary “send a pulse of growth hormone.” It taps the bell when you’re empty and lets go; MK-677 is a key that holds that same doorbell down on a once-a-day schedule. More GH pulses lead the liver to make more IGF-1, the messenger that does most of growth hormone’s real work in muscle, bone, and connective tissue. Because it amplifies your own pulses instead of replacing the hormone outright, MK-677 mostly keeps the natural rhythm of GH release — the feature that made it an appealing oral stand-in for injected growth hormone. The trade-off is baked into that same design: MK-677 has a long half-life, so it nudges IGF-1 up around the clock instead of in a clean pulse, and that round-the-clock elevation is a big part of where the water retention comes from.

Does MK-677 actually work? What the science says

Here’s the part the sales pages blur: MK-677’s evidence is unusually strong for a research-market compound — it sits at Human RCT, not the animal-only tier most of its neighbors live at — but “strong evidence” answers a narrower question than most buyers assume.

What the trials nail down, over and over, is the mechanism. Across randomized human studies, MK-677 reliably raises growth hormone and IGF-1, pushing IGF-1 up toward the range of a younger adult (indexed trials). That’s the most reproduced finding in the whole literature, and it holds. The best body-composition data comes from a two-year randomized trial in healthy older adults, where MK-677 increased fat-free (lean) mass versus placebo (NCT00474279). That’s the good news, and it’s real.

Now the seams. In that same two-year trial, the extra lean mass didn’t clearly translate into more strength or better physical function — and some of what a body scan counts as “lean mass” is retained water, not contractile muscle. And every time MK-677 was pointed at an outcome people actually care about, the story cooled: it ran through a completed Phase 2 Alzheimer’s trial (NCT00074529) and a hip-fracture recovery program (NCT00128115) and wasn’t carried forward as a treatment in either.

So my read, with the evidence sitting right here: MK-677 does exactly what it was engineered to do — it moves the biological dials — and the proof that those moved dials become the things people buy it for, usable muscle and real-world function, is still thin. That’s not a dead end; it’s a narrow, testable gap. And the most serious attempt to close it is running now: the identical molecule, as LUM-201, is in Phase 3 trials for children with growth hormone deficiency (NCT06948214) — a real pharmaceutical program that will say far more about what this molecule does than any bulk log ever could.

Is MK-677 safe? Side effects

MK-677’s safety picture is unusually well-documented, and it’s mixed. Because it has been through real human trials, its side effects are recorded rather than guessed at.

The consistent ones: increased appetite (it’s a hunger-receptor agonist, so this is the drug working as designed), fluid retention with mild swelling or edema, and higher fasting blood sugar with reduced insulin sensitivity — that last one matters a great deal for anyone who has, or is trending toward, type 2 diabetes. Many users also report short-lived fatigue, lethargy, or achy joints in the first weeks, and some get numbness or tingling in the hands, a carpal-tunnel-type effect driven by the same fluid retention pressing on nerves.

The most serious signal came from a trial in frail elderly hip-fracture patients, which was stopped early after more heart-failure events in the MK-677 group (NCT00128115). That result weighs heaviest for older users and anyone with cardiovascular risk, and it’s the single most important safety fact on this page. Separately, MK-677 raises IGF-1 for as long as you take it, and whether years of elevated IGF-1 changes long-term cancer risk is an open, unsettled question — reason for real caution in anyone with a personal or family cancer history.

One more layer has nothing to do with the molecule and everything to do with the market: MK-677 sold online is an unregulated research chemical. Because it arrives as a pill or a dropper bottle you simply swallow — not something most buyers would ever send to a lab — the actual milligrams in each dose are whatever the seller printed on the label, with no regulator checking the claim. Long-term use in otherwise-healthy adults hasn’t been studied at all.

FDA & legal status (2026)

MK-677 is not an FDA-approved drug, is not part of any approved medicine, and is not a lawful dietary supplement as of July 15, 2026 — the FDA has taken the position that ibutamoren doesn’t qualify as a dietary ingredient, which is why you’ll never see it on a compliant supplement label even though it turns up in gray-market “sports” products (FDA drug information; FDA scientific review of ibutamoren mesylate). In the United States it’s sold strictly as a research chemical.

The moving part worth watching: the identical molecule is in Phase 3 development as LUM-201 for children with growth hormone deficiency, so if that program succeeds, part of MK-677’s regulatory story could shift. Treat every legal claim here as dated, and re-check it.

Question	Status on July 15, 2026	What it means
FDA approval	Not approved	No FDA-reviewed MK-677 indication, label, or drug product exists
Dietary supplement	Not a lawful dietary ingredient (FDA position)	Can’t be sold for human consumption; “sports” products using it are non-compliant
Research-chemical sales	Sold online, “research use only”	Being available doesn’t make it approved, safe, or legal to consume
Elite sport	Banned at all times — WADA S2	Named as a growth-hormone secretagogue; there’s no in-competition-only loophole

For tested athletes, this one isn’t a gray area. Ibutamoren is named on the WADA Prohibited List under S2 (growth hormone secretagogues) and is banned both in and out of competition (USADA / WADA Prohibited List). A positive test won’t care that you bought it labeled “research chemical.”

MK-677 dosing: what studies used vs. what people run

MK-677 has one dose with real evidence behind it and a wider range people run on their own. The best-documented human studies, including the two-year older-adults trial, used 25 mg once daily by mouth (NCT00474279) — that’s the number with data attached. Community use skews lower and more variable, commonly 10–25 mg a day and often taken at night, but those figures are anecdotal, listed here to inform rather than to prescribe a protocol.

Because MK-677 is oral, the two tools that matter for injectable peptides don’t apply: there’s no powder to reconstitute and nothing to draw into a syringe, so the reconstitution calculator and the mixing-compatibility reference aren’t relevant here.

Source	MK-677 dose	What it tells us
Two-year older-adults RCT (NCT00474279)	25 mg once daily, oral	The best-evidenced human dose; raised IGF-1 and lean mass
Community use (anecdotal)	10–25 mg/day, often at night	What people run on their own — not a validated protocol

MK-677 vs. the injectable GH secretagogues

MK-677 is usually weighed against the injectable growth-hormone secretagogues — most often the CJC-1295 + ipamorelin stack, and single peptides like ipamorelin on its own. The plain difference is delivery and evidence: MK-677 is a once-daily oral molecule with real human RCTs behind its GH/IGF-1 effect, while the GHRH/GHRP peptides are subcutaneous shots taken once or more a day that lean far more on animal and short-term human data.

They aren’t really competing for the same job, which is why “which one’s best” is the wrong question. MK-677’s edge is convenience and evidence depth — a pill, and actual randomized trials. Its drawbacks are the flip side of its own design: the water retention, the blood-sugar effects, and a long half-life that keeps IGF-1 elevated around the clock instead of pulsing and clearing the way the injectables (and your own body) do. If the whole reason someone’s looking is “I don’t want to inject,” MK-677 is the obvious oral pick; if pulse-clean GH release and staying dry matter more, the short-acting injectables read better. None of them is an FDA-approved physique drug. For the wider family, see the growth-hormone hub.

Frequently asked questions

Does MK-677 cause water retention and bloating?

Yes — it’s the most common thing people report, and often the reason they stop. MK-677 raises growth hormone and IGF-1 around the clock, which makes the body hold extra fluid: a puffier face, a bloated midsection, sometimes swollen ankles, and a scale that climbs a few pounds of water in the first week or two. For many people the bloat eases after three to four weeks; for others it never settles enough to be worth it. Lower doses generally mean less of it.

Why does MK-677 make you so hungry?

Because it switches on the ghrelin receptor — the same “you’re hungry” signal your empty stomach uses. That hunger is the mechanism working, not a malfunction, which is what makes it reliable enough to help mid-bulk and brutal enough to end most attempts to run it during a cut. The hunger usually ramps up 30 to 60 minutes after a dose, which is part of why many people take it at night.

Does MK-677 actually build muscle?

It reliably raises IGF-1 and increased fat-free mass in a two-year older-adults trial (NCT00474279) — but that added mass didn’t clearly become more strength or function, and some of it is retained water. So MK-677 changes body composition on a scan; whether that’s meaningful, usable muscle for a healthy lifter isn’t proven. Treat scale gains as mostly water and food until strength backs them up.

Is MK-677 a peptide, a SARM, or a steroid?

None of the three. MK-677 is an oral non-peptide small molecule that activates the ghrelin receptor to raise your own growth hormone, so it’s best described as a growth-hormone secretagogue. It’s often sold next to SARMs and lumped in with them, but it isn’t a SARM and isn’t a steroid — it works through a completely different mechanism.

Should you take MK-677 in the morning or at night?

There’s no validated answer — this is a community timing preference, not a clinical instruction. People who dose at night do it to ride the sleep benefit and to sleep through the appetite spike; people who switch to the morning usually do it because a nighttime dose left them groggy or gave them dreams too vivid to rest through. Both patterns are widely reported, and neither comes from a trial.

Is MK-677 legal, and is it banned in sport?

In the US, MK-677 is sold only as a research chemical — not an FDA-approved drug and not a lawful dietary supplement, so it can’t legally be sold for human consumption (as of July 15, 2026). And for tested athletes it’s a hard no: ibutamoren is on the WADA Prohibited List under S2 (growth-hormone secretagogues), banned at all times, in and out of competition.

Who MK-677 is (and isn’t) for

MK-677 tends to pull in lifters who want the recovery, sleep, and appetite that ride along with higher growth hormone but don’t want to inject anything to get them — usually during a bulk, where a bigger appetite and fuller muscles are features rather than bugs. It’s also one of the very few compounds in this space where “does it do anything measurable?” earns a confident yes: it raises GH and IGF-1, it added lean mass in a two-year trial, and it’s taken seriously enough to sit in Phase 3 as a real drug. Going in clear-eyed — wanting the sleep and the bulk support, able to live with some water and a lot of hunger, and not mistaking scale weight for proven muscle — it’s a reasonable thing to be curious about.

It’s a poor fit, or worth real caution, for a longer list of people. Anyone with diabetes or prediabetes has to reckon with the blood-sugar and insulin-sensitivity hit. Anyone with a history of heart failure or meaningful cardiovascular risk should weigh that terminated frail-elderly trial heavily. Anyone with a personal or family cancer history has to sit with the unsettled long-term-IGF-1 question. Tested athletes are out (S2, banned at all times), and it’s not for pregnant or breastfeeding people. And if the whole goal is a lean cut, the appetite alone will probably fight you the entire way.

What’s solid: MK-677 raises GH and IGF-1, and it does it by mouth — that much is well-evidenced. What’s still uncertain: whether the added lean mass becomes usable muscle and function, and what years of round-the-clock IGF-1 do to long-term health. So, back to the pill you came looking for. It’s real, it works at the thing it was built to do, and the honest unknowns are specific and finally being tested — the LUM-201 Phase 3 program is, right now, turning “it moves the dials” into a much clearer picture of what this molecule actually delivers. For the neighborhood it lives in, see the growth-hormone hub and how MK-677 compares to research peptides like AOD-9604, BPC-157, and TB-500.