Also known as Enobosarm, Ostarabolic, or by its original research chemical name, MK2866, Ostarine is not an anabolic steroid.
It belongs to a newer form of experimental performance-enhancing drugs known as SARMs (Selective Androgen Receptor Modulators).
SARMs are a relatively new medical field, aimed not only at enhancing performance and physique.
Like all other SARMs, it is currently an investigational new drug and has not yet been manufactured and administered as an actual medicine.
It is currently participating in clinical trials.
Ostarine was originally developed by Merck & Co. and later acquired by GTX, Inc.
The intended uses for Ostarine are treating muscle wasting diseases and osteoporosis, with most research and clinical trials focused in this area.
The potential for it to prevent/treat other conditions such as cachexia, sarcopenia, and for Hormone or Testosterone Replacement Therapy (TRT) is also being researched.
Like other compounds in the SARM family, Ostarine selectively binds to and activates androgen receptors in the human body, promoting effects such as muscle gain, preventing fat accumulation, and increased strength.
It does this while avoiding the androgen receptors in other parts of the body where side effects can occur, such as the prostate, scalp, and skin.
This has led to significant interest in Ostarine within the athletic and bodybuilding communities, so much so that in January 2008, the World Anti-Doping Agency developed a blood test capable of detecting it.
Ostarine is known to be the most purely anabolic of all currently commercially available anabolic compounds.
Ostarine (MK-2866) Chemical Characteristics
Chemically, like all other SARMs, Ostarine does not resemble the traditional anabolic steroid structure at all.
The chemical structure of Ostarine has not been fully disclosed by GTX, Inc.
While the company hasn’t officially published the chemical structure of Ostarine, the chemical composition can be found in patent databases (e.g., WIPO) and has been discussed in literature from various major research sources.
It is important to note that Ostarine is often incorrectly linked to the chemical structure of Andarine (also known as S-4).
Specifically, Ostarine is known as an arylpropionamide.
It differs from Andarine in that the nitro and acetamido moieties on the phenyl ring are replaced by a cyano substitution.
Ostarine Side Effects
Research indicates that taking Ostarine in amounts greater than recommended can suppress the body’s endogenous natural testosterone production in males.
The same side effect can occur with long-term use of Ostarine for more than 5 weeks.
Therefore, Ostarine does actually suppress the Hypothalamic-Pituitary-Testicular Axis (HPTA), necessitating some form of Post-Cycle Therapy (PCT) protocol.
Since Ostarine is not inherently an anabolic steroid, it lacks the typical side effects of anabolic steroids beyond those already mentioned in this section.
Ostarine does not exhibit known estrogenic, androgenic, hepatotoxic, or cardiovascular side effects.
It should be noted that, like all other anabolic steroids, Ostarine is at a very new and early stage of development as a pharmaceutical and PED (Performance Enhancing Drug), so currently unknown side effects may be discovered through future research or individual use.
Ostarine Dosage and Administration
Most users tend to take between 12.5mg and 50mg of Ostarine per day for performance and physique enhancement, with 50mg certainly being the upper limit.
In one study conducted over 3 months on 120 elderly individuals who did not weight train, Ostarine resulted in dose-dependent increases in lean body mass, with the group receiving the highest dose (3mg per day) showing an average lean mass gain of 3.1 pounds.
Anecdotal reports from bodybuilders and athletes using this compound suggest that 25mg per day seems to be the most perfect and common dosage.
Dosages exceeding 30mg per day are generally only recommended for individuals weighing approximately 210 pounds or more, as HPTA suppression effects begin to manifest at this point.
For injury, bone, and joint healing purposes, one can experience satisfactory results even with a minimum dosage of 12.5-15mg per day.
Ostarine is nearly perfect for female users, so women can do well within a range of 6-12.5mg per day.
Ostarine is administered orally, and with a half-life of approximately 24 hours, it can be taken once or twice daily.
The individual can decide whether to take half the daily dose in the morning and the other half in the evening.
Ostarine Cycle
Ostarine cycles are run in the range of 5 to 8 weeks.
Those who do not wish to experience the potential for HPTA suppression and cessation of endogenous testosterone production are advised to keep their Ostarine cycle to 5 weeks or less.
Maintaining a cycle longer than 5 weeks (or a dosage significantly exceeding 25-30mg per day) will require some form of PCT protocol after the cycle ends.
Some users have ventured into uncharted territory, running Ostarine for cycles as long as 16 weeks and stacking/overlapping it with other SARMs like Andarine or Cardarine.
Ostarine has also found other types of uses, including ‘bridging’ between anabolic steroid cycles.
Bridging refers to utilizing another compound between anabolic steroid cycles to maintain muscle mass.
These bridging compounds generally share the commonality of not suppressing, or at least minimally suppressing, the HPTA while still promoting anti-catabolism and muscle growth.
Ostarine During Post-Cycle Therapy (PCT) and Ostarine Bridging
While using SARMs during PCT and as a bridging compound has become a common usage philosophy (and there are logical reasons for doing so), Ostarine is an exception.
Using Ostarine is not recommended because it has the side effect of suppressing the HPTA, thereby inhibiting endogenous natural testosterone production.
This was mentioned earlier, and there is research showing decreased plasma testosterone levels after Ostarine administration.
However, if you wish to pursue this course, do not exceed 25mg per day.
Dosages exceeding this threshold lead to more severe testosterone suppression.
This is why a PCT protocol is absolutely necessary following Ostarine use itself, and many recommend using PCT even after a short Ostarine cycle as an additional safety measure in this regard.
Similarly, using Ostarine as a bridge between anabolic steroid cycles, while it has become a practice among some bodybuilders, is also not recommended.
While many in the athletic and bodybuilding communities initially thought this was a good idea when Ostarine first appeared in the PED scene, research and individual experience indicate it is generally not a good idea.
While one could use Ostarine at a low dose, the fact that there are other SARMs more suitable for this purpose that do not negatively impact the HPTA has essentially rendered Ostarine obsolete for this purpose very quickly.
Ostarine Availability and Legality
Since Ostarine is not yet an FDA-approved, fully developed pharmaceutical or drug, finding Ostarine products for medicinal use is impossible.
It is currently only known as a research chemical sold very widely on the internet and worldwide.
It currently only exists in the form of liquid research chemicals for use in research laboratories, not for human use.
The lack of regulation for research products carries the disadvantage that there are companies which underdose or fake Ostarine, although this is not known to be a common concern or occurrence.
It can be legally purchased, possessed, and used in most countries and regions around the world, including the United States, Canada, and the United Kingdom.
It is currently classified by the FDA as an IND (Investigational New Drug).
All drugs or compounds in IND status must include a ‘Caution’ label: “Caution: New Drug – Limited by Federal (or United States) law to investigational use.”
