MK-677 (Ibutamoren) vs Mod GRF 1-29 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 →Mod GRF 1-29
Mod GRF 1-29 (Modified GRF 1-29, also called CJC-1295 without DAC or Tetrasubstituted GRF 1-29) is a modified growth hormone-releasing hormone analog with improved stability over natural GHRH.
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) | Mod GRF 1-29 | 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 growth hormone release. Four amino acid substitutions improve resistance to enzymatic degradation while maintaining biological activity. | 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: 100-300mcg administered 2-3 times daily, usually combined with a GHRP like Ipamorelin for synergistic effects. | 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. Best administered on empty stomach. Short half-life (~30 minutes) necessitates multiple daily doses, unlike DAC version. | 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. | Flushing, headache, dizziness, and injection site reactions. Generally well-tolerated. May cause water retention. | May cause temporary fatigue, headache, or localized irritation at injection sites. |
| Best For |
What They Have in Common
MK-677 (Ibutamoren), Mod GRF 1-29, TB-500 are all commonly used for:
Key Differences
Unique to MK-677 (Ibutamoren):
Unique to Mod GRF 1-29:
Detailed Analysis
Commonalities
Both MK-677 (Ibutamoren) and Mod GRF 1-29 are commonly used for Muscle Growth, Fat Loss, Recovery & Healing, Sleep Quality.
Which Should You Choose?
MK-677 (Ibutamoren) has stronger evidence for 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 Mod GRF 1-29 and TB-500 are commonly used for Muscle Growth, Recovery & Healing.
Which Should You Choose?
Mod GRF 1-29 has stronger evidence for Muscle Growth. TB-500 has stronger evidence for Recovery & Healing.