Ostarine (MK-2866), also known as ostabolic or Enobosarm was originally developed by GTX Pharmaceuticals to prevent muscle loss in people suffering from muscle wasting conditions such as HIV and cancer.
GTX pharmaceuticals presented the results of a phase2 clinical trial evaluating Ostarine (MK-2866) in patients with cancer induced muscle loss (also known as cancer cachexia) at the Endocrine Society Annual Meeting, held in Washington 2009. In this study 159 cancer patients with cell lung cancer, colorectal cancer, non-Hodgkins lymphoma, chronic lymphocytic leukemia or breast cancer were randomized. Participants received a placebo, 1mg or 3mg Ostarine daily for 16 weeks. Patients were allowed to receive standard chemotherapy during the trial. Ostarine treatment led to statistically significant increases in lean body mass (LBM) and improvement in muscle performance in both the 1mg and 3mg cohorts. The primary endpoint of LBM was measured by a dual energy x-ray absorptiometry (DEXA) scan. Ostarine demonstrated significant increases in LBM compared to baseline with average increases of 1.3kg and 1.5kg of LBM at the end of the 16-week trial, in the 1mg and 3mg groups respectively. The study also met the secondary endpoint of muscle function as measured by a 12-step stair climbing test measuring speed and calculating power, with each Ostarine treatment group demonstrating a statistically significant decrease in time to completion and increase in power exerted 3.
In clinical studies, Ostarine has consistently demonstrated increases in LBM and better physical function across several populations, along with a lower hazard ratio for survival in cancer patients. Full results from these studies will soon be published and will guide the development of future anabolic trials. While Ostarine was initially trialed at 0.1 mg, 0.3 mg, and 1 mg per day, dosages as high as 9 mg and 18 mg per day have been studied and were generally well tolerated by both men and women in a less commonly known phase II clinical trial.
Lean gains upwards of 5 – 10 pounds are typical among recreational users, with average dosages ranging from 12.5 – 25 mg per day in 8-12-week cycles.
More and more recreational steroid users are including Ostarine in their Post Cycle Therapy. As a SARM, ostarine selectively binds to the androgen receptors in muscle tissues. Ostarine continues activating androgen receptors while the PCT drugs nolvadex and clomid bring natural testosterone production back to normal. This continued activation prevents loss of muscle mass or strength during the PCT.
However, research shows that higher doses of ostarine can cause HPTA suppression so you wouldn’t want to use too high of an ostarine dosage in your PCT. However, the suppression isn’t too much of an issue because when you use ostarine in conjunction with a SERM like nolvadex (tamoxifen) or clomid (clomiphene), the stimulation of the pituitary and hypothalamus from the nolvadex/clomid offsets the mild suppression from the ostarine. In other words, nolvadex and clomid get your endogenous testosterone levels back to normal while ostarine offers the therapeutic benefits of increased androgen receptor activity.
“Ostarine was originally my favourite SARM because it did everything that I was hoping SARMS would do – increase strength and performance, improve recovery, build muscle, maintain muscle while dieting and give my muscles a dry hard look. However, I no longer use ostarine very much because it’s very mild. It’s a great compound for beginner and intermediates but advanced users won’t see much benefit.
Women – 5mg per day or 5mg every other day, up to 10mg per day seems to have the most benefits with the least amount of side effects. I do know professional female athletes that use up to 30mg/day. But they often start to get swelling of the clitoris and an extreme sex drive at that dosage.
Men – in my early days of using ostarine, I used 20mg/day to maintain muscle mass after a steroid cycle. At 10mg/day I started losing size. I noticed a big difference between 10 and 20mg. I really liked a daily 20mg dosage because I felt like I wasn’t experiencing any symptoms of low testosterone and in fact, my testosterone levels were actually recovering. I’ve taken up to 100mg/day. I didn’t notice any additional benefits taking dosages higher than 50mg/day. I think it plateaus at around 50mg/day.
I don’t have too much to say about ostarine because I really don’t use it much. It’s more beneficial for beginner users and females.
Side note – A older female friend of mine with osteoporosis found huge therapeutic benefits from supplementing with ostarine at 10mg/day.”
- Dr tony huge
“I’m not a big fan of oral ostarine but the injectable version could be very good. There is a lot of clinical information on injectable ostarine. Lots of research using only 1-2mg/day with impressive results. I’m going to start experimenting with the injectable form. I am not sure on dosage recommendations because I haven’t used it yet.”
- Coach Trevor