MK-677 (Ibutamoren) vs Sermorelin
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
MK-677 (Ibutamoren)
MK-677, also known as Ibutamoren, is an orally active growth hormone secretagogue. Unlike peptides, it can be taken orally and has a long half-life, providing 24-hour GH elevation.
Full details →Sermorelin
Sermorelin is a synthetic analog of GHRH consisting of the first 29 amino acids of the natural hormone. It was previously FDA-approved for GH deficiency diagnosis and treatment in children.
Full details →Side-by-Side Comparison
| Aspect | MK-677 (Ibutamoren) | Sermorelin |
|---|---|---|
| Dose Range | 10 mg–25 mg | 100 mcg–300 mcg |
| Frequency | 1x daily | 1x daily |
| Cycle Length | 8–24 weeks | 8–12 weeks |
| Route | oral | subcutaneous |
| Mechanism | Acts as a potent, selective agonist of the ghrelin receptor (GHS-R1a). Increases GH and IGF-1 levels without affecting cortisol. Mimics ghrelin's GH-releasing effects. | Binds to GHRH receptors in the pituitary gland to stimulate natural GH production and release. Maintains the body's natural feedback mechanisms for GH regulation. |
| Typical Dosage | Typical dosing: 10-25mg taken orally once daily. Often taken at night due to sleep benefits and appetite increase. | Typical dosing: 200-500mcg administered once daily, usually before bed. Some protocols use twice daily dosing. |
| Administration | Oral administration (capsule or liquid). Can be taken with or without food. Long half-life allows once-daily dosing. | Subcutaneous injection, preferably at bedtime to work with natural GH release patterns. Can be combined with GHRPs for synergistic effects. |
| Side Effects | Increased appetite and water retention are most common. May cause lethargy, vivid dreams, and mild numbness. Can affect blood glucose and insulin sensitivity. | Generally well-tolerated. May cause injection site reactions, headache, flushing, or dizziness. Less side effects than direct GH administration. |
| Best For |
What They Have in Common
MK-677 (Ibutamoren), Sermorelin are both commonly used for:
Which Has Stronger Evidence?
- Muscle Growth: MK-677 (Ibutamoren) has stronger research support.
- Sleep Quality: MK-677 (Ibutamoren) has stronger research support.
| Goal | MK-677 (Ibutamoren) | Sermorelin |
|---|---|---|
| Muscle Growth | high | medium |
| Fat Loss | medium | medium |
| Recovery & Healing | medium | medium |
| Sleep Quality | high | medium |
Key Studies
MK-677 (Ibutamoren)
- Knowing the minimal detectable dose can facilitate the interpretation of a hair test result: II. Case example with ibutamoren (MK-677), a growth hormone secretagogue.
Clinica chimica acta; international journal of clinical chemistry, 2026
- Hepatotoxicity induced by MK-677.
BMJ case reports, 2025
- Investigating the P53-dependent anti-cancer effect of ibutamoren in human cancer cell lines.
Basic & clinical pharmacology & toxicology, 2025
Sermorelin
- A potentially effective drug for patients with recurrent glioma: sermorelin.
Annals of translational medicine, 2021
- Sermorelin: a better approach to management of adult-onset growth hormone insufficiency?
Clinical interventions in aging, 2006
- Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency.
BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy, 1999
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