MK-677 (Ibutamoren) vs Sermorelin vs TB-500
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 →TB-500
Thymosin Beta-4 (TB-500) is a naturally occurring peptide present in almost all human and animal cells. It plays a crucial role in tissue repair and regeneration.
Full details →Side-by-Side Comparison
| Aspect | MK-677 (Ibutamoren) | Sermorelin | TB-500 |
|---|---|---|---|
| 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. | TB-500 promotes cell migration and differentiation, regulates actin (a cell-building protein), and reduces inflammation. It supports the formation of new blood vessels and wound healing. |
| 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. | Research protocols typically use 2-2.5mg twice weekly during the loading phase, followed by maintenance dosing of 2mg every 2 weeks. |
| 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. | Administered via subcutaneous or intramuscular injection. Some protocols suggest injection near injury sites. |
| 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. | May cause temporary fatigue, headache, or localized irritation at injection sites. |
| Best For |
What They Have in Common
MK-677 (Ibutamoren), Sermorelin, TB-500 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 TB-500 are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for Muscle Growth. TB-500 has stronger evidence for Recovery & Healing.
Commonalities
Both Sermorelin and TB-500 are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
TB-500 has stronger evidence for Recovery & Healing.