MK-677 calculator
An oral growth-hormone secretagogue (not a peptide) studied in human trials. Investigational; raises appetite and blood sugar.
Also known as: Ibutamoren, MK677, Oral GH secretagogue
FDA status — not an approved drug Not FDA-approved for any use. MK-677 (ibutamoren) is an investigational oral drug that has been through human trials but is not approved. It is prohibited in sport.
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What MK-677 is
MK-677 (ibutamoren) is an oral small-molecule growth-hormone secretagogue — not a peptide — that mimics ghrelin to raise growth hormone and IGF-1. It has been through real human trials showing it works, but it was not approved, partly over concerns about blood sugar, fluid retention, and a heart-failure signal. It is prohibited in sport.
Research depth: 3/5 Real human trials confirming GH/IGF-1 elevation; not approved over safety concerns. Human trials: Phase 2 trials. This measures how much has been studied — counting animal and laboratory work — not whether it works for you.
How MK-677 works
It activates the ghrelin receptor (GHSR-1a), stimulating the pituitary to release growth hormone and raising IGF-1. Because it is orally active and long-acting, it produces sustained elevation rather than a pulse. The ghrelin activity also strongly stimulates appetite, and the sustained GH/IGF-1 elevation affects blood sugar and fluid balance.
MK-677 side effects
Commonly reported
- Marked increase in appetite
- Water retention and swelling
- Elevated blood sugar and reduced insulin sensitivity
- Fatigue and lethargy
- Muscle aches
Serious — seek medical care
- Raises blood sugar and reduces insulin sensitivity — a concern for diabetes risk
- A heart-failure signal appeared in one trial in older adults
- Sustained GH/IGF-1 elevation raises theoretical cancer concern
- Prohibited in sport by WADA
This list is not exhaustive. Report anything unexpected to the clinician who prescribed it. If you have severe abdominal pain, trouble breathing, or signs of an allergic reaction, seek care the same day. See also our guide to peptide side effects by class.
A worked example
A 25 mg vial reconstituted with 1 mL of bacteriostatic water gives 25 mg/mL. A 25000 mcg dose is then 1 mL — about 100 units on a 100-unit insulin syringe, giving roughly 1 doses per vial before accounting for residual volume left in the vial and syringe.
Prefer paper? Download the printable MK-677 dosing chart (PDF) — every vial size and water volume in syringe units, with the same review byline as this page. All charts →
Commonly cited dose range
Figures circulating for MK-677 run from 10000 mcg to 50000 mcg. MK-677 is taken orally in milligrams, not reconstituted or injected. Figures shown are total milligrams in micrograms — 25,000 mcg is 25 mg. It is a capsule/liquid oral drug, not a reconstituted peptide.
Read this as reference information, not instruction. These numbers describe what is commonly discussed, not what is right for any individual. Dose, frequency, and whether to use MK-677 at all are decisions for a licensed clinician who knows your history.
Common questions
Is MK-677 a peptide?
No. MK-677 (ibutamoren) is an oral small-molecule growth-hormone secretagogue, not a peptide. It is taken by mouth and does not need reconstitution. It appears on peptide lists because it targets the same ghrelin receptor as peptide secretagogues.
Has MK-677 been tested in humans?
Yes — it has been through human trials for growth-hormone deficiency and muscle wasting, showing it raises GH and IGF-1. It was not approved, partly over concerns about blood sugar and heart failure signals.