Muscle & performanceAnti-aging & longevity
MK-677
Ibutamoren · MK-0677 · Ibutamoren mesylate
MK-677 does not belong in this category on chemistry. It is a small molecule — not a peptide — and it is taken orally rather than injected. It is grouped with peptides because it is discussed, sold and used alongside them, and pretending otherwise would be less useful than saying so.
It acts on the same ghrelin receptor as ipamorelin, but because it is orally bioavailable with a long half-life, it produces sustained elevation of growth hormone and IGF-1, not a pulse. It was developed as a pharmaceutical candidate and taken into clinical trials, so more human data exists for it than for most compounds here, including a trial that was stopped.
That trial is the most important thing on this page. A study in older adults with hip fracture was discontinued after an excess of congestive heart failure in the treatment group. Whether that reflects a causal effect is debated, and it is exactly the kind of finding that only emerges when a compound is actually studied. That is why the absence of trials elsewhere on this site is not reassuring.
How it works
MK-677 mimics ghrelin at its receptor, prompting growth hormone release from the pituitary and increasing appetite. Both effects follow from the same mechanism.
Its long half-life means once-daily oral dosing produces continuously raised GH and IGF-1, not the pulses that secretagogue peptides produce. This is the substantive difference from ipamorelin, and it cuts against the 'preserves natural pulsatility' argument used for the injectable class.
Sustained IGF-1 elevation is also what makes the cardiac and glucose findings mechanistically plausible rather than merely coincidental.
Regulatory status — United States
Not approved for human use in any jurisdiction. Development was not completed. It is widely sold as a 'research chemical' or mislabelled as a dietary supplement, which it is not. It is an unapproved drug.
Last reviewed 12 Aug 2026. Regulatory positions in this category change frequently; we date this line so you can see how current it is.
What it is studied for
Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.
Growth hormone and IGF-1 elevation
Clinical trialWell demonstrated in trials.
EvidenceRandomised trials in older adults showing sustained increases in GH and IGF-1 over months.
Lean mass
Clinical trialIncreases in lean body mass have been measured.
EvidenceA randomised trial in healthy older adults found increased lean mass over 12 months, without a corresponding improvement in strength or function.
Appetite stimulation
Clinical trialFollows directly from ghrelin receptor agonism.
EvidenceConsistently reported in trials and in community use.
Identity and clearance
Molecule
- Class
- Non-peptide small molecule, ghrelin receptor agonist
- Molecular weight
- 528.66 Da
Not a peptide. Included here because it is used and discussed alongside them, not because it belongs to the same chemical class.
Pharmacokinetics
Clinical trialA roughly 24-hour half-life is what allows once-daily oral dosing, and what produces sustained rather than pulsatile GH elevation.
Dose protocols reported in sources
Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.
| Goal | Dose | Frequency | Route | Units | Source | Start this protocol |
|---|---|---|---|---|---|---|
| Trial dose in older adults | 25 mg | Once daily, oral | OralTaken by mouth. Nothing about this compound is reconstituted or injected. | — | Clinical trial | Start this |
| Commonly described dose | 10 mg – 25 mg | Once daily, usually at night | Oral | — | Community practice | Start this |
Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.
CheckRows marked community practice describe what people commonly do, drawn from public discussion. They are not derived from any trial and are not evidence that a dose is safe or effective.
Safety
Reported effects
- Marked increase in appetiteClinical trial
Very common
The most consistently reported effect, and often pronounced. It follows directly from ghrelin receptor agonism.
- Water retention and swellingClinical trial
Common in trials
- Raised blood glucose and reduced insulin sensitivityClinical trial
Documented in trials
A consistent finding, and mechanistically expected, since growth hormone opposes insulin.
- Lethargy and daytime drowsinessCommunity practice
Commonly reported
- Congestive heart failure in one trial populationClinical trial
Serious, and the reason a trial was stopped
A study in older adults with hip fracture was discontinued after an excess of congestive heart failure in the treatment group. Causality is debated. It is the single most important safety signal associated with this compound.
When to stop
- Shortness of breath, particularly lying down or at night, or waking breathless. Seek medical care. These are features of heart failure, and this compound carries a signal for it.
- Swelling of the ankles or legs that does not settle overnight.
- A rapid or irregular heartbeat, or chest discomfort.
- Unusual thirst, frequent urination or blurred vision, which can indicate raised blood glucose.
- Any new lump or growth. Sustained IGF-1 elevation makes this worth investigating rather than watching.
Interactions and situations that need care
- Any heart failure or significant cardiac historyAvoid
A trial in older adults with hip fracture was stopped early after an excess of congestive heart failure in the treatment group. Whatever the eventual explanation, this is a documented signal in a studied population and not a theoretical concern.
- Diabetes or impaired glucose toleranceAvoid
Reduced insulin sensitivity and raised blood glucose were consistent findings in trials, not occasional ones. This works directly against glycaemic control.
- Active or previous cancerAvoid
Sustained IGF-1 elevation over months promotes cell proliferation. Continuous elevation is a different exposure from the brief pulses the injectable secretagogues produce.
- Pregnancy and breastfeedingAvoid
No reproductive or developmental safety data.
- Competing in a tested sportAvoid
Prohibited at all times under WADA's S2 category, which names growth hormone secretagogues regardless of chemical class.
SportProhibited by the World Anti-Doping Agency under S2: Peptide Hormones, Growth Factors and Related Substances, at all times. Growth hormone secretagogues are explicitly named regardless of chemical class.
What to expect
- Increased appetite is close to universal and often substantial. If you are eating at a deficit, this is working against you.
- In a 12-month randomised trial in healthy older adults, lean mass increased. Strength and physical function did not improve alongside it.
- Raised blood glucose and reduced insulin sensitivity were consistent findings rather than occasional ones.
- The heart failure signal from the discontinued hip fracture trial is the thing to weigh most heavily, and it is the kind of finding that only appears when something is actually studied.
Storage and handling
- Freeze-dried powder
- Not applicable. This is not supplied as a lyophilised peptide. Powder or capsules should be kept cool, dry and out of light.
- After mixing
- Not applicable. Liquid preparations sold in solution should follow the seller's storage instructions, which is a weaker guarantee than it sounds.
With other peptides
That blend contains ipamorelin, which is also a ghrelin-receptor agonist. Running both doubles one mechanism while adding this compound's own effect on insulin sensitivity.
- HGH (Somatropin)caution
This raises growth hormone by driving the pituitary. Adding the hormone itself stacks the same signal, including the insulin resistance both cause.
- Testosterone (TRT)caution
Both cause fluid retention, and this also worsens insulin sensitivity. The combination compounds oedema and metabolic effects.
- Ipamorelincaution
Both act on the ghrelin receptor. Combining them stacks one mechanism rather than adding another, and compounds the hunger and water retention.
- IGF-1 LR3caution
MK-677 raises IGF-1 by driving growth hormone, and worsens insulin sensitivity on its own. Adding exogenous long-acting IGF-1 compounds both the proliferative signal and the glucose effects, from two directions at once.
In use
Stacks with MK-677 in them
Documented combinations, with full schedules.
Questions
- Is MK-677 a peptide?
- No. It is a small molecule taken orally. It appears alongside peptides because it is sold and discussed in the same places and acts on the same receptor as ipamorelin, but chemically it is a different kind of compound and nothing about it is reconstituted or injected.
- Why was a trial stopped?
- A study in older adults recovering from hip fracture was discontinued after an excess of congestive heart failure in the treatment group. Whether the compound caused it is debated, but it is a documented signal in a studied population and the most important safety consideration here.
- Does it build muscle?
- A 12-month randomised trial in healthy older adults found increased lean body mass. It did not find corresponding improvements in strength or physical function, and a good part of early lean mass gain on this compound is water.
References
Oral ghrelin mimetic MK-677 and growth hormone secretion in healthy older adults
Annals of Internal Medicine / clinical trial literature, 2008 · Randomised, double-blind, placebo-controlled trial
Healthy older adults · n = 65 · 25 mg once daily, oral · 12 months
Sustained increases in GH and IGF-1, and increased lean body mass, without improvement in strength or function. Raised fasting blood glucose and reduced insulin sensitivity were observed.
10.7326/0003-4819-149-9-200811040-00003
Commonly reported community protocols
Bioalmanac editorial summary of public community sources, 2026 · Not a study
Summarises the oral dose ranges most consistently described in public discussion. Carries no evidential weight about safety or effect.
MK-677 compared with
MK-677 vs HGH
An oral secretagogue against injected growth hormone. Cheaper, needle-free and indirect on one side. The hormone itself, dosed in IU, on the other.
MK-677 vs ipamorelin
Same receptor, opposite shapes. One is an oral small molecule producing sustained elevation; the other is an injected peptide producing a short pulse. Only one of them has a trial that was stopped early.
Related compounds
Tesamorelin / CJC-1295 / Ipamorelin
Three growth hormone secretagogues in one vial, commonly 6:3:3. Two of the three do the same job, which is the thing worth knowing before buying it.
HGH (Somatropin)
An approved medicine for people with a growth hormone deficiency. Used without that diagnosis it is a controlled substance in the United States, and the anti-ageing claims it is sold on were retracted by their own author.
Testosterone (TRT)
Not a peptide, and the most consequential thing on this site. Approved replacement therapy for diagnosed hypogonadism — a Schedule III controlled substance — and something that will make you infertile while you take it.
Ipamorelin
A selective growth hormone secretagogue that prompts a short pulse of GH release. Widely used, and supported almost entirely by early pharmacology rather than outcome trials.
Next
What to do with MK-677
- Keep a record of itTurn a dose and a schedule into a protocol, then log what you actually take. MK-677 is filled in for you.
- See what it costsPer-milligram prices read from vendor sites and confirmed by a person, so vial sizes compare.
- Check a combinationWhat our profiles record about MK-677 alongside each other compound — including the pairs where nothing is recorded.
Keep this page honest
If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.
This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on Bioalmanac is medical advice. No clinician reviews these pages.
Page last updated 12 Aug 2026