Growth Hormone

MK-677

Ibutamoren Mesylate

The oral GH secretagogue - no injection required

MK-677 (ibutamoren) is an orally active, non-peptide GH secretagogue. It raises GH and IGF-1 levels for up to 24 hours from a single oral dose.

MK-677 illustration
💉

Admin routes

Oral

🔥

Popularity

High

✅

Side effects

Generally mild

🏪

AU vendors

0 rated

✓Key benefits

1Oral administration - no injections needed
224-hour duration of action from single dose
3Increases IGF-1 by ~40% within 2 weeks
4Improves sleep quality and deep sleep duration
5Supports bone density and muscle mass
6Maintained GH response without desensitisation in 2-year studies

📈What to expect

1
Week 1–2

Increased appetite; improved sleep quality and depth

2
Week 2–4

Water retention; IGF-1 levels rising (~40% increase)

3
Week 4–8

Body composition changes; improved recovery

4
Week 8–12+

Sustained GH/IGF-1 elevation; monitor blood glucose

Based on community reports and published research. Individual results vary significantly.

💊Dosing protocols

GH optimisation

Dose

10–25 mg

Frequency

Once daily (before bed)

Duration

8–12 weeks or longer

Muscle/bone support

Dose

25 mg

Frequency

Once daily

Duration

12+ weeks

Dosing information is sourced from published research and community protocols. This is not a recommendation. Consult a healthcare professional.

Research status|Phase 2 clinical data available - not FDA-approved

Overview

MK-677 (ibutamoren) is a non-peptide, orally active growth hormone secretagogue that mimics ghrelin's action at the GHS-R1a receptor. Unlike injectable GH peptides, MK-677 can be taken as a capsule or liquid and maintains elevated GH and IGF-1 levels for up to 24 hours from a single dose. It was developed by Merck and has been studied in clinical trials for muscle wasting, osteoporosis, and GH deficiency.

⚙️How it works

Binds to ghrelin (GHS-R1a) receptors in the hypothalamus and pituitary, stimulating GH release. Being non-peptide, it survives stomach acid and has excellent oral bioavailability. A single 25 mg dose increases GH pulsatility and raises IGF-1 levels by approximately 40% within 2 weeks. Like GHRP-6, it increases appetite due to ghrelin receptor activation.

⚡Side effects

Increased appetite
moderateCommon
Water retention and bloating
mildCommon
Lethargy and fatigue initially
mildCommon
Elevated fasting blood glucose
moderateUncommon
Numbness and tingling in extremities
mildUncommon

📅Research history

1995

Developed by Merck as an orally active GH secretagogue

1998

Clinical trial data in elderly adults published

2008

2-year study in healthy older adults published in Annals of Internal Medicine

2010s

Massive adoption in bodybuilding and anti-aging communities

2020s

One of the most popular oral peptide alternatives worldwide

MK-677 vs injectable GH peptides

The main advantage is convenience - no reconstitution, no syringes, no refrigeration. The trade-off is a less selective profile: MK-677 raises appetite and can affect blood glucose, similar to GHRP-6. For those who want GH benefits without injections, it's the most practical option. For those prioritising a clean side-effect profile, injectable ipamorelin/CJC-1295 remains superior.

Blood sugar monitoring

MK-677 can raise fasting blood glucose and impair insulin sensitivity, particularly at 25 mg doses. Anyone with prediabetes, diabetes, or metabolic syndrome should monitor glucose levels carefully. Some practitioners add berberine or metformin alongside MK-677 to mitigate this effect.

References

  1. [1]Murphy MG, et al. 'Effect of alendronate and MK-677, a growth hormone secretagogue, individually and in combination on markers of bone turnover.' Journal of Clinical Endocrinology & Metabolism, 2001.
  2. [2]Nass R, et al. 'Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults.' Annals of Internal Medicine, 2008.

Frequently asked questions

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Need to calculate your dose?

Use our free reconstitution calculator to work out syringe units for MK-677.

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Disclaimer: This guide is for educational and informational purposes only. It is not medical advice. The dosing protocols listed are sourced from published research and community reports and do not constitute a recommendation. Always consult a qualified healthcare professional before using any peptide. Australian regulations classify many peptides as Schedule 4 (prescription-only) substances. Check current TGA guidelines before purchasing.