Ostarine Side Effects

By: Juice

Last updated:

SteroidCycle.org is intended for informational purposes only and does not take the place of professional medical advice.

Ostarine is one of the more advanced SARMs when it comes to the research and study that’s been done on it, but like all SARMs it still has no approval for any medical uses so you can never be sure just how your body will respond to it.

Ostarine Side Effects
Ostarine Side Effects

This hasn’t stopped bodybuilders and athletes taking notice of the potential for Ostarine to increase lean muscle growth and promote fat loss without the side effects of anabolic steroids.

But how side effect friendly is Ostarine really? Can you use this SARM without any risk to your health, and is it worth it for the benefits you might experience?

Discover everything you need to know about Ostarine’s short and long term side effects so you can decide whether you should be using it.

Author’s Note: The following guide is based on my personal experience and does NOT promote the illegal use of SARMs.

What is Ostarine (MK-2866)

Ostarine is a type of compound called a SARM – Selective Androgen Receptor Modulator. SARMs come with similar anabolic properties to anabolic steroids, but their effect on androgen receptors is very different. As the name indicates, a nonsteroidal SARM like Ostarine is selective in the androgen receptors it targets.

Ostarine MK-2866 Structure
Ostarine MK-2866 Structure

It’s important to know that Ostarine, like all SARMs, is classed as an investigative drug only. It has no approval for any medical use, and scientific data and studies are minimal. As far as SARMs go, there are more studies on Ostarine compared to other compounds but it is still a very limited amount of data regarding both the benefits and possible side effects and long term health effects of using Ostarine.

It is the potential anabolic effects of Ostarine that has made it a compound that appeals to bodybuilders and athletes. The possibility of gaining muscle with no androgenic side effects seems to good to be true for those of us who have suffered with the side effects of steroids for many years. But that is the whole point of SARMs being researched for future medical use: to provide the positives of steroids like testosterone with as few negatives as possible.

Some other names you might see for Ostarine include MK-2866, Enobosarm and GTx-024. Because Ostarine has no approved medical use, the only way to obtain it is through a loophole that allows its purchase in liquid form for research purposes.

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What does Ostarine do?

Ostarine features strong anabolic activity and, like steroids, increases protein synthesis and nitrogen retention – the basic processes of muscle growth. Ostarine can be thought of as a very all round SARM that is useful for both bulking and cutting. Its anabolic effects are useful for maintaining muscle mass while dieting, while at higher doses impressive muscle gains can be achieved.

Ostarine Effects
Ostarine (MK-2866) Effects

The two main uses you will have for Ostarine are to gain muscle and lose fat, so let’s look at how this works:

Lean muscle gains

Ostarine can work similarly to steroids when it comes to promoting muscle gains, but importantly it can do this by specifically targeting those androgen receptors that are important for lean gains: those in the skeletal muscle.

This avoid the targeting of androgen receptors in most other places and is why you don’t get those steroid induced androgenic side effects along with your gains. Studies in elderly people – a cohort that is unlikely to be indulging in the kind of intensive weight lifting and high calorie/high protein dieting of bodybuilders – resulted in notable gains in lean muscle and in muscular strength even at low doses.

This gives us a solid indication of Ostarine’s ability to promote muscle gains even where average levels of physical activity are taking place. It shows the potential for gaining muscle once you really ramp up your workout and diet to encourage bigger gains.

Fat burning

Ostarine has shown to have a positive impact on insulin sensitivity and the metabolism that can lead to easier and faster weight loss. This includes both types of fat: subcutaneous and visceral fat loss will occur as long as your diet is ideal.

Many users not in particular that weight around the waist is far easier to lose (an area where men tend to store excess fat). A major benefit is the lack of water retention, so you’ll have no bloat to deal with as you burn off fat.

Joint health and healing are some of the very welcome additional benefits of Ostarine and may help with recovery.

The benefits of Ostarine must include just how female friendly this compound is. Many women would love the benefits of anabolic steroids, but are rightly scared off by the very real prospect of severe virilization that comes with steroid use.

Ostarine does away with those risks and women are able to confidently use this SARM without worrying about the development of masculine features. Women can experience the same impressive muscle gains and fat loss as male Ostarine users.

Short-Term Side Effects

As with most SARMs, the known side effects when Ostarine is used at performance doses mostly come from the experience of those who have come before us. At this point, Ostarine has been used by a lot of people and we have a good idea of what side effects to expect.

The good news is that Ostarine is showing to be a fairly side effect friendly compound. It is certainly much more “friendly” in this way when compared to the harsh side effects of most anabolic steroids.

In fact, even the mildest steroids are likely to result in worse side effects than most of us will experience with Ostarine.

Any short term Ostarine side effects will be of the type that should disappear once you stop using the SARM, or at some point during your cycle. In other words, these are temporary side effects that shouldn’t (as far as we know) cause any longer term effects.

Firstly, androgenic effects are not going to be an issue with Ostarine. There’s no DHT conversion and that means it won’t directly cause androgenic side effects like acne and hair loss. This also means Ostarine is ideal for women because there’s no risk of virilization as is the case with steroids.

Estrogenic side effects are very unlikely, but not completely impossible. Ostarine does not aromatize, so there’s no estrogen conversion happening. But Ostarine can potentially bring about a slight rise in estrogen through other ways.

Particularly sensitive individuals might find this causes some mild estrogenic side effects, but you should balance the thought of using an anti-estrogen drug with the possibility that it can cause a dangerous drop in estrogen levels (remembering that males still require low levels of estrogen). Few Ostarine users will find estrogen related effects to be an issue overall.

If you’re familiar with steroids you’ll be well aware of their impact on cholesterol. Once again Ostarine has good news because the data so far shows minimal to no impact on cholesterol levels – certainly not at any level approaching that of most steroids. Those with good cardiovascular health should find that Ostarine is not a risk.

At higher doses, Ostarine can cause some level of testosterone suppression. Although it won’t be anywhere near as bad as that caused by steroids, some men will still need to do PCT after a high dose Ostarine cycle to get that natural testosterone production back on track.

Long-Term Side Effects

Without any robust and long term clinical trials and other studies, it’s impossible to know if Ostarine is going to cause any long term side effects or health complications. While its short term use certainly seems harmless enough, can we really know if anything is lurking that won’t rear its head into well into the future – potentially after you’ve used Ostarine for many years? We can’t know, therefore using Ostarine is purely at your own risk.

One aspect we are aware of is that using Ostarine at high doses and for long periods of time can potentially cause significant testosterone suppression in men. Whether or not this is going to be at the same level as anabolic steroids will come down to each individual, but there’s o doubt that the HPTA (Hypothalamic Pituitary Testicular Axis) is impacted at these high doses.

Repeated, long term, high dosage Ostarine use could cause long term damage to the HPTA. With moderate use all men should be able to avoid this preventable problem, and with use of PCT after an Ostarine cycle (especially when human chorionic gonadotropin (hCG) is included), suppressed function should be completely reversible in most cases.

If you’re an experienced steroid user you would already be concerned about long term side effects like cardiovascular health (such as cholesterol and blood pressure) and liver toxicity. Ostarine comes without these long term risks which gives you some peace of mind that you do not have when using most steroids.

Hepatotoxic Side Effects (Liver Toxicity)

You would be used to knowing that oral steroids generally have a harsh and dangerous effect on the liver. Ostarine is also an oral compound but it doesn’t come with the risk of liver toxicity. Ostarine isn’t a C17-alpha alkylated drug, nor is it any other type of compound that causes hepatotoxicity.

Despite this, there are rare reports of individuals who experienced a form of liver injury who used Ostarine or other SARMs for several weeks and then did PCT afterwards.

It is well worth noting that the PCT in question were pre-formulated products rather than drugs that experienced steroid users make use of like Nolvadex and Clomid. Potentially it was the PCT products themselves that brought about liver injury, rather than Ostarine.

As more and more people use Ostarine and other SARMs we could see more cases like this emerging, and eventually it will shed more light on whether these are rare individual events that may or may not be directly linked to Ostarine, or if injuries or damage to the liver starts to become more commonplace.

As of today, there are still very few reports of complications regarding Ostarine’s effects on the liver and few people yet see it as something to be concerned about.

HPTA and Endogenous Testosterone Production Side Effects (Testosterone Suppression)

It is possible that men can experience some testosterone suppression with Ostarine. This won’t be as severe as it is with steroids and everyone will have a different response. Some guys will use a testosterone support supplement, but other won’t find it necessary.

You run a greater risk of having some suppression when using Ostarine at higher doses. Additionally, using it for longer than about 5 weeks is likely to increase the risk of some testosterone suppression happening.

Some men will choose to run a 5 week cycle of Ostarine only to avoid suppression, but those using it for anywhere between 5 and 8 weeks will likely need some PCT afterwards.

Gynecomastia and Water Retention

Ostarine does not cause any estrogenic side effects. This means you won’t be worry about gyno or water retention. This makes Ostarine very appealing for cutting and building a defined, dry physique. And any muscle gains you make won’t consist of water and you should find the gains easier to maintain post cycle.

Even though Ostarine doesn’t cause any estrogen conversion, it can potentially raise estrogen levels slightly. This is unlikely to be at a level where you need to worry about fluid retention or gyno developing, and increases in estrogen are much more likely at high doses of Ostarine.

Once again, we can see how using Ostarine at sensible doses does tend to mitigate or completely prevent these unwanted side effects – something that is not necessarily easy to do with most anabolic steroids.

Women Specific Side Effects

SARMs in general are much easier for women to use than anabolic steroids. Gone are the awful androgenic side effects including virilization. Women can use Ostarine without the worry of masculine physical traits developing.

Of the few studies conducted with Ostarine to date, some have been with elderly participants and this includes elderly women. The women in these studies who used Ostarine at low doses experienced no sign of virilizing effects.

Without studies at much higher doses it’s impossible to predict whether females would see any surprising side effects, but given Ostarine’s lack of activity on androgen receptors away from skeletal muscle and bone, the risk of any virilization when using Ostarine at performance doses is likely to be non-existent.

Ostarine is often described as the perfect SARM for women for these reasons.

Is Ostarine Safe?

Although Ostarine has a small amount of data and some research done on its effects, it is still very much a research and investigational drug. This means there’s a whole lot we don’t know about it still, and without the long term clinical trial data that approved drugs have, there’s no way of knowing for sure whether using Ostarine now is going to compromise your health in the future.

Using any SARM, including Ostarine, is entirely at your own personal risk because it’s not possible to say for certain whether Ostarine is safe or not.

What is known at this point is that Ostarine is side effect friendly in the short term, and there’s little evidence from users that it has a negative effect once you stop using it.

Want to minimize the risk of Ostarine becoming unsafe? Utilize only moderate doses, avoid the temptation for excessive doses, and keep your cycles to the recommended length of 5-8 weeks at the most. Importantly, you should avoid use of all SARMs for at least one month after ending a cycle to allow your body to fully recover.

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Does Ostarine lower testosterone?

There is some evidence that high doses and prolonged use of Ostarine can cause a reduction in testosterone levels. Some men using this SARM at high doses will experience testosterone suppression and will need to do PCT following an Ostarine cycle.

This is much more likely when using Ostarine at doses above 20mg per day for longer than 8 weeks, although sensitive individuals could certainly see negative impacts at lower doses in some cases.

Does Ostarine have side effects?

Very few side effects have been reported so far with Ostarine. Minor testosterone suppression and slight increases in estrogen when Ostarine is used at higher doses are some reported side effects.

As Ostarine is a very new and under-researched drug so far, there may be other side effects that are discovered in future. Ostarine is not known to cause the very serious side effects that anabolic steroids do in the areas of cardiovascular and liver health.

How safe is Ostarine?

Ostarine is still an investigational compound so it’s full safety level can not be known. What is know is that thousands of bodybuilders and performance athletes have used Ostarine and continue to use it, with most reporting minimal or no short term side effects.

Using Ostarine is at your own risk because of the lack of study and research to date on its potential long term health impacts. Short term, low dose studies on humans have found no serious negative effects so far.

Does Ostarine increase estrogen?

Even though Ostarine doesn’t aromatize and lead to estrogen conversion, it may still cause a small rise in estrogen levels in some users. This is more likely if it’s used at a high dose or for long cycles. Most users will see no increase in estrogen, and that means no water retention – resulting in a dry and defined physique.

Does Ostarine cause hair loss?

No, Ostarine does not cause any androgenic side effects so you will not experience male pattern baldness when using this SARM. This is because Ostarine is designed to target specific androgen receptors and it does not convert to DHT while is a primary cause of hair loss.

All SARMs including Ostarine are prohibited substances due to its performance enhancing effects. Many athletes have tested positive to Ostarine over the years. So while you’re operating in a gray area when using Ostarine for personal use, if you use it in the sporting arena where you’re likely to get tested, you could find yourself in serious legal jeopardy.

Where can I buy Ostarine?

Ostarine has no approved pharmaceutical use and so is not manufactured as a retail product. You can buy Ostarine as a research chemical through research manufacturing labs and a one month supply can cost you up to $200 depending on your source.

Final Thoughts

Ostarine is one of the most side effect friendly compound we’ve seen to date. It is very usable by females, and also provides males with a viable alternative to the harsh effects of anabolic steroids. Despite its relatively mild side effect profile, the Ostarine results are surprisingly powerful.

But Ostarine still comes with that big unknown factor. We simply have no idea whether it’s going to cause long term health complications. You’re also dealing with an unproven research chemical that researcher might one day discover is significantly more harmful than is known today.

Is it worth the risk? For many of us, the answer is a clear no. Ostarine isn’t legal to use in sports or competition, and you run the risk of a poor quality product when buying MK-2866 from labs.

About the Author
Juice Lewis, Author of SteroidCycle.org
Juice Lewis

Real-life Experience, not Theory

I don't claim to know everything; what I talk about here is something I've done. From anabolic steroids to HGH, to peptides, insulin, and supplements, I've done it at some point in my life, and I can relate.