MK-677 (Ibutamoren) vs Thymalin
Side-by-side comparison of key properties, dosing, and research.
Growth Hormone Peptides
MK-677 (Ibutamoren)Immune SupportAnti-Aging & Longevity
Thymalin- Summary
- MK-677 (Ibutamoren) is an orally active, non-peptide ghrelin receptor agonist that increases growth hormone and IGF-1 levels. Unlike injectable GHRPs, it can be taken orally and has a 24-hour half-life, making it convenient for sustained GH optimization.
- Thymalin is a polypeptide complex isolated from calf thymus glands (developed by the Russian Gerontology Institute), shown to restore immune function, extend lifespan, and reverse thymic involution. Clinical studies demonstrate improved immune parameters and up to 40% reduction in mortality in elderly patients.
- Half-Life
- 24 hours
- Not well characterized as a complex extract; individual peptides have varying kinetics
- Admin Route
- Oral
- SubQ, IM
- Research
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- Typical Dose
- 10–25 mg
- 10 mg IM or SC daily
- Frequency
- Once daily
- Once daily
- Key Benefits
- Increases lean muscle mass
- Enhances bone density
- Improves sleep quality and REM sleep
- Accelerates recovery from training
- Increases appetite
- May improve skin elasticity and appearance
- Supports fat loss while maintaining muscle
- Oral administration — no injections required
- 24-hour half-life allows once-daily dosing
- Restores thymic function and T-cell immunity
- Extends healthy lifespan (documented in long-term studies)
- Reduces infectious disease incidence in elderly
- Normalizes immune parameters in immunodeficiency
- Anti-tumor immune surveillance
- Improves vaccine response in elderly
- Reduces cardiovascular mortality (40% in landmark Russian study)
- Normalizes neuroendocrine function
- Side Effects
- Increased appetite (significant in some users)
- Water retention and puffiness
- Elevated blood glucose / insulin resistance (monitor in diabetics)
- Lethargy initially
- +2 more
- Very well tolerated in decades of Russian clinical use
- Mild injection site reactions
- Rare: mild allergic reaction (natural extract)
- Transient flu-like symptoms on initiation (immune activation)
- Stacks With
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