MK-2866, also known as ostarine or Enobosarm, is an investigational selective androgen receptor modulator. for the treatment of conditions such as muscle wasting and osteoporosis. Ostarine  can improve strength and promote muscle growth. 

Sarms like Ostarine are taken to inhibit muscle loss when cutting calories in the diet. Users can take one dose daily for 6 to 8 weeks to aid recomposition. Ostarine has a half-life of 24 hours (according to most medically reviewed research and studies), so taking it multiple times per day is not necessary. One dose of 10-20mg every day is all that is required.