What is Ostarine?
Ostarine, also called MK-2866 or Enobosarm, is probably the most clinically studied SARM. It was developed by GTx Inc as a therapeutic candidate for muscle-preservation indications, such as cancer-related muscle wasting.
In the research community Ostarine is regarded as the mildest member of the class: lower suppression, lighter side-effect load than RAD-140 or LGD-4033. Mild does not mean harmless.
How it works
Ostarine binds the androgen receptor and activates it preferentially in muscle and bone tissue. In studies this was associated with gains in lean mass and improved physical function.
It does not aromatize and is not reduced to DHT. Suppression of the body's own axis is present but lower compared with stronger SARMs.
How to take it
Oral, once daily.
- One dose per day is enough given the roughly 24-hour half-life.
- With some water, with or without food.
- Cycles often run over 8 weeks with a break afterwards.
Dosing
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What the research shows
A phase 2 study (Dalton, 2011) in healthy older men and postmenopausal women associated Ostarine with gains in lean mass and better physical function. A further phase 2 study (Dobs, 2013) tested Enobosarm against muscle wasting in cancer patients and saw improvements in lean mass and function.
That gives Ostarine the most solid human data record among SARMs, yet no approval exists.
Side effects
- Suppression of the testosterone axis, milder than with stronger SARMs but present.
- Falling HDL values in longer setups.
- Rarely liver value changes at higher doses.
Practice
- A good entry SARM, still start low (12.5mg).
- Limit cycles, then take a break.
- Banned in official competition and detectable for weeks (WADA S1.2).
- Check blood values before and after the cycle.
Storage
Store dry, cool and protected from light, out of reach of children. Keep the original container closed and mind the expiry date.