MK-677 (Ibutamoren) vs Sermorelin vs Tesamorelin
A three-way comparison to help you find 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 →Tesamorelin
Tesamorelin is a synthetic analog of growth hormone-releasing hormone (GHRH). It is FDA-approved under the brand name Egrifta for reducing excess abdominal fat in HIV-infected patients with lipodystrophy.
Full details →Side-by-Side Comparison
| Aspect | MK-677 (Ibutamoren) | Sermorelin | Tesamorelin |
|---|---|---|---|
| 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. | Stimulates the pituitary gland to produce and release growth hormone by binding to GHRH receptors. Increases IGF-1 levels which promotes lipolysis and reduces visceral adipose tissue. |
| 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. | FDA-approved dose: 2mg administered subcutaneously once daily. Research protocols may use various dosing schedules. |
| 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. | Subcutaneous injection into the abdomen. Rotate injection sites. Best administered at the same time daily, preferably in the evening. |
| 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. | Common side effects include injection site reactions (erythema, pruritus), joint pain, peripheral edema, and muscle pain. May cause elevated blood glucose. |
| Best For |
What They Have in Common
MK-677 (Ibutamoren), Sermorelin, Tesamorelin are all commonly used for:
Key Differences
Unique to MK-677 (Ibutamoren):
Unique to Sermorelin:
Detailed Analysis
Commonalities
Both MK-677 (Ibutamoren) and Sermorelin are commonly used for Muscle Growth, Fat Loss, Recovery & Healing, Sleep Quality.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Muscle Growth, Sleep Quality.
Commonalities
Both MK-677 (Ibutamoren) and Tesamorelin are commonly used for Muscle Growth, Fat Loss.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Muscle Growth. Tesamorelin has stronger evidence for Fat Loss.
Commonalities
Both Sermorelin and Tesamorelin are commonly used for Muscle Growth, Fat Loss.
Which Should You Choose?
Tesamorelin has stronger evidence for Fat Loss.