Thymosin Alpha-1 vs MK-677 (Ibutamoren)
Side-by-side comparison of key properties, dosing, and research.
Immune SupportAnti-Aging & Longevity
Thymosin Alpha-1Growth Hormone Peptides
MK-677 (Ibutamoren)- Summary
- Thymosin Alpha-1 is a naturally occurring 28-amino acid peptide derived from the thymus gland. It is a powerful immune modulator approved in many countries for treating chronic hepatitis B, hepatitis C, and as an adjunct in cancer immunotherapy.
- 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.
- Half-Life
- 2–3 hours
- 24 hours
- Admin Route
- SubQ
- Oral
- Research
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- Typical Dose
- 0.8–1.6 mg
- 10–25 mg
- Frequency
- Twice weekly
- Once daily
- Key Benefits
- Enhances T-cell and NK cell activity
- Supports recovery from viral and bacterial infections
- May reduce inflammation systemically
- Supports healthy aging and immune resilience
- Improves vaccine response
- Supports liver health
- May help with chronic fatigue syndrome and post-viral conditions
- Approved in multiple countries for hepatitis B and C treatment
- 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
- Side Effects
- Injection site irritation
- Mild flu-like symptoms initially (immune activation)
- Fatigue (rare)
- Increased appetite (significant in some users)
- Water retention and puffiness
- Elevated blood glucose / insulin resistance (monitor in diabetics)
- Lethargy initially
- +2 more
- Stacks With
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