Ostarine (MK-2866) SARM 101: The Bodybuilder’s Guide

When I first started looking into SARMs as a complement (and alternative) to anabolic steroids, Ostarine was a name that kept coming up in my research.

Countless people were using it for their first SARM experience (guys and girls) with claims of body composition transformation and hardly any side effects to worry about. Too good to be true? The only way to find out was to try it myself, and that’s precisely what I did…

In this guide, I reveal all that I’ve personally discovered about Ostarine. Keep reading if you want to know all the pros and cons of doing an Ostarine cycle and some of the best stacks to achieve specific goals using Ostarine and other powerful PEDs. Let’s jump in!

What is Ostarine?

Ostarine, or MK-2866, is one of the oldest SARMs and one of the most popular.

We can understand what Ostarine can do by knowing it was originally researched as a possible treatment for osteoporosis and muscle wasting conditions.

Unlike a lot of SARMs and other PEDs, which have minimal scientific data available, Ostarine has been studied in depth and has proven without doubt that it is effective at targeting bone and muscle tissue to stimulate positive results – with an impressively small side effect risk.

History and Overview

You might see Ostarine being sold under other names like Ostabolic or Enobosarm. But its official chemical name is MK-2866.

Ostarine is a SARM – Selective Androgen Receptor Modulator. This puts it in the category of an investigational drug. As you are no doubt aware by now, SARMs have gained the attention of bodybuilders and athletes over the past several years thanks to their incredible benefits for physique enhancement and athletic performance.

GTX Inc. is the company that had been in control of the development and clinical trials of Ostarine, until recently. The main possible medical uses that researchers have been interested in with this SARM are:

• Osteoporosis
• Muscle wasting conditions
• Testosterone replacement therapy

After a merger with another company a few years ago, the future of Ostarine research is uncertain. There’s a good chance that the development of this SARM has come to an end, and there may never be any future clinical trials or further research.

Like all SARMs, Ostarine’s performance enhancement benefits for athletes have long been known, and as a result, it’s listed as a prohibited substance in professional sports.

Mechanism of Action

Why should you care about the mechanism of action of Ostarine? Well, it’s especially useful when it comes time to plan how and with what other PEDs to stack Ostarine with.

Each PED works a little differently from the next, and you can create an excellent synergy when combining Ostarine with something else that compliments its mechanisms of action. It helps you avoid more side effects AND delivers better results – as simple as that.

Like all SARMs, Ostarine will selectively bind to specific androgen receptors after you’ve ingested it. Muscle and bone are the primary targeted receptors. But Ostarine isn’t perfect; no SARM is. This means some non-target receptors might also be targeted, which could produce extra unwanted effects.

Compared to anabolic steroids, which can bind to all androgen receptors, Ostarine is MUCH more targeted and, therefore, isn’t capable of producing the more harsh side effects that come with most steroids.

Effects of Ostarine (Benefits)

You might have seen Ostarine called a “weak” SARM, especially in terms of its ability to promote muscle gains. Still, I can tell you that Ostarine can provide enough anabolic power to produce nice, clean, lean muscle gains at a moderate level. No, it’s not going to rival something like Dianabol, but you don’t go into using Ostarine with those types of expectations, or you’re bound for disappointment.

We know it’s a scientific fact that Ostarine is capable of increasing lean muscle mass. Not only that, but it’s also a fact that it improves physical performance. How do I know? An important study on 120 healthy elderly men and women aged over sixty found clear evidence that Ostarine increased lean body mass and exercise capability^[1]. The increase was dose-dependent (participants took no more than 3mg or less for three months).

It’s no secret that elderly people experience loss of muscle as age progresses and find it harder to gain muscle. This points to Ostarine being a far more powerful muscle builder than a lot of people give it credit for. Consider this: Bodybuilders and athletes take more than 3mg/day of Ostarine, so you can expect those anabolic effects to ramp up with weight training.

With all that said, Ostarine is not even valued first and foremost for muscle growth! Ostarine works to protect existing lean muscle very well, and this makes it ideal for cutting cycles. It’ll help promote some fat loss, but just how much it helps with losing fat is still a matter of argument.

In the real world, the amount of fat you will lose will depend on many factors beyond Ostarine itself. Still, you can build a potent cutting or shredding cycle when stacking Ostarine with other known fat-burning agents like Cardarine.

There’s more to Ostarine than just a focus on muscle growth or maintenance, though. It will also:

• Increase strength, especially when you’re dieting and would otherwise see a loss of strength.
• Performance enhancement: stamina and cardiovascular ability increase (run/swim/cycle harder and longer).
• Bone strength: increases bone mineral density and bone volume density^[2]
• Joint and tendon strengthening
• More vascularity and muscle definition thanks to the lack of water retention
• Faster recovery so you can get back in the gym sooner

As you can see, Ostarine is a nice all-rounder SARM and suits multiple goals rather than only being a bulking or cutting compound.

I like that both men and women can use it and that the balance of positives to negatives does lean towards Ostarine, a SARM that has more pros than cons for most of us (I go over the possible downsides in the “side effects section” below).

Ostarine Dosing and Administration

You only have to look at some of the studies done on Ostarine to know that dosing matters. As with any PED, we aim for a balance of:

• Achieving maximum benefits
• While reducing side effect risk to a minimum

The good news is that Ostarine is relatively easy to get the dosage right for an optimal balance of the above. It’s pretty well established among long-time SARM users that Ostarine produces the best performance enhancement and bodybuilding results within the dosage range I’ve outlined below.

Here’s what you need to know:

Doses

Clinical studies of Ostarine (which means those studies involving human participants) were typically done at doses that are well below what we would want to use for performance purposes.

And you know what?

Even those low doses brought about impressive results. This is the fundamental difference between clinical and bodybuilding doses of Ostarine:

• Clinical Trials Doses: 1mg to 3mg
• Bodybuilding Doses: 10mg to 25mg. Advanced users may go as high as 50mg.

Here’s a general guide to Ostarine bodybuilding doses for different experience levels:

Beginner

Beginners will see excellent results on a first cycle of 10mg daily for eight weeks.

Intermediate

15-25mg daily is a comfortable range that will take results with Ostarine to an impressive level without magnifying adverse effects beyond a tolerable level. A lot of people will be very happy never to take more than 25mg of Ostarine (I’m one of them), no matter what level of experience you have in bodybuilding.

Advanced

25mg is still considered an advanced dose of Ostarine. Some users will take 30-50mg, but I think it’s a waste of time and money because the results will not be much better than at 25mg, and the side effects will be much worse.

My thoughts? You’re better off stacking instead of increasing Ostarine’s dose too high.

Female

10mg is the typical female dosage and can yield significant lean gains because women will always be more sensitive to the anabolic effects of Ostarine.

Bioavailability, Half-life, and Cycle Length

Ostarine has been shown to have very high bioavailability in animal studies, which means your body absorbs it very well, and you get the maximum effect of the full dosage (as long as you’ve bought high-quality Ostarine).

Ostarine’s half-life is about 24 hours. What does this mean for you? You can conveniently take your dosage just once daily – ideally at the same time each day.

With the lower doses used in clinical trials, Ostarine was often used for longer periods than we would with a bodybuilding cycle. Clinical studies were generally in the 12-16 week range.

Bodybuilding and performance cycles of Ostarine typically run for between 8 and 12 weeks but sometimes as short as 4 to 6 weeks.

Dosing Schedule and Administration Methods

The 24-hour half-life means you can take Ostarine just once daily at the same time each day to maintain optimal levels of the SARM.

Ostarine is sold almost exclusively in liquid form. Some vendors might sell tablets or capsules, but liquid is the most common product and is simple to administer.

A liquid suspension of Ostarine is taken either orally or sublingually (placed under the tongue), and thanks to its excellent bioavailability, you’ll be getting the full effects of your chosen dose.

Ostarine Cycles

You can run Ostarine on its own (recommended for brand-new users) or as part of a stack with other synergistic compounds.

Stacking is a perfect way to achieve more specific goals (more on that below). But an Ostarine-only cycle is still going to deliver the goods for both men and women – and it’s the best way to dip your toes into the water when using this SARM for the first time.

Ostarine Cycle for Men

20mg-25mg for 8-12 weeks is a perfect cycle for guys. If you’re new? Stick to 8 weeks the first time. But if you’re feeling confident and want to continue your gains and/or fat loss on the cycle, 12 weeks is doable, provided these values are within the healthy range (this is why bloodwork is essential):

• Testosterone levels
• Cholesterol
• Liver values

If the above hasn’t deteriorated during the first eight weeks, you should be good to continue for another 2-4 weeks.

Expected results will be focused on body fat reduction and muscle retention. I never gain much lean mass on a cycle like this, but that’s not the goal here (if it is, try one of the recommended stacks). Depending on your current body fat, expect to lose at least 10lbs on this cycle with the right diet.

What are people saying about this cycle?

The good: I and most guys experience near zero side effects of any type. That’s because the dosage is reasonable and moderate rather than excessive. Reports of strength either staying the same or not increasing a whole lot can be considered a neutral experience. Don’t expect big strength gains, but Ostarine should be helping maintain your energy on a calorie deficit where you’d otherwise feel more fatigued.

Negative reviews and comments about this cycle tend to focus on the expected side effects of some testosterone suppression (you should be planning how to deal with this if it arises), acne in sensitive users, and headaches in a small number of guys. That’s about it.

An Ostarine cycle for men is, for the majority of us, going to be a well-tolerated and successful cycle resulting in noticeably improved body composition.

Ostarine Cycle for Women

5-10mg per day for 4 to 8 weeks will provide substantial anabolic effects for women, who can more easily gain a good amount of lean muscle with Ostarine. These gains will come while simultaneously burning fat.

Women can expect increased muscle definition and vascularity, with the only limit being that of diet and training. A good calorie-deficit diet combined with intensive cardio training is going to make this a true cutting cycle, with a shredded physique as the ultimate goal.

What experiences are women having with an Ostarine cycle? As long as the dosage is kept low, as above, and cycle length is limited, females don’t report any virilization with this SARM.

As with male users, females can also be at risk of negative cholesterol and liver changes on this cycle, but unless bloodwork is done, few women report issues in these areas.

Positive comments from women on an Ostarine cycle always focus on the amount of fat lost (varies wildly between individuals, depending on diet and training). But muscle gains are substantially higher for women, with 25 lbs of gains being reported by some women – and these gains are maintainable after the cycle ends for most females.

Ostarine vs. Other PEDs

How does Ostarine compare to other PEDs? Whether they be SARMs, SARM-like compounds, or anabolic steroids (AAS). As you would expect, Ostarine will compare most closely to other SARMs due to their similar mechanism of action.

Some SARMs, like Andarine, can give similar results to Ostarine, while other more potent SARMs, like Ligandrol, will deliver substantially more muscle gains. But those more powerful SARMs will also give you a worse side effect experience than Ostarine.

What about anabolic steroids compared to Ostarine? You won’t get AAS-level results with Ostarine (but you also won’t get those nasty sides either). If you look at a very low dose of the mildest of steroids, like Anavar, you could compare it to Ostarine. But almost any other anabolic steroid will blow Ostarine out of the water in terms of muscle gain and performance potential (so will their side effects, I might add).

Stacking Ostarine

There’s nothing wrong with using Ostarine on its own. If it’s your very first time trying Ostarine, running it as the sole compound for one cycle is the perfect introduction to this SARM. But more importantly, it gives you a clear idea of how YOU respond to Ostarine – both the good and bad.

Once you’re comfortable taking things to the next level, stacking Ostarine with one or more other SARMs or PEDs is a whole new ball game regarding results and performance. Ready to see my top Ostarine stacks? Here they are:

Ostarine + Cardarine (Cutting Stack)

If you’re confident in using Cardarine considering its known risks, then one of the best stacks you can do for cutting is Ostarine and Cardarine. This killer combo is going to give you plenty of fat loss (mostly from Cardarine), while Ostarine takes care of muscle preservation and maintaining strength while you’re dieting.

Females will find that Ostarine is an excellent muscle builder, so women can expect some more significant gains than men on this cycle (if the diet supports growth).

Benefits

Fat loss can be significant, with Cardarine, in particular, being a potent fat burner. This stack will make subcutaneous and visceral fat much easier to lose.

Ostarine helps maintain existing muscle if you’re on a calorie deficit, and you can also find yourself GAINING muscle with this stack. It won’t be significant, but combined with loss of body fat, you can expect impressive physique enhancement and muscular definition.

Cardiovascular performance will be enhanced substantially. Increased stamina and endurance will allow you to extend your workouts and increase their intensity, speeding up fat loss further.

Dosing

Cardarine should be dosed low for safety reasons and used for no more than 12 weeks. But we will limit our use to eight weeks here as this is more than enough for excellent results.

Men and women can run Ostarine for eight weeks at 15mg and 10mg daily. Some men will extend this to 20mg, but women should maintain no more than 10mg daily. At the same time, for eight weeks, Cardarine can be taken at 10mg/day for women and 10-20mg/day for men.

Possible side effects

Based on animal studies, Cardarine is well known for its potential cancer risk. Keeping its use to no more than 12 weeks is where most people are comfortable. Women will find no virilization with Ostarine as long as no more than 10mg daily is taken.

Mild to moderate testosterone suppression is possible in men – consider my PCT advice elsewhere in this guide to decide whether or not you should do PCT. Stress to the liver is more than possible with this stack, but values should return to normal in healthy users. Ostarine can also increase blood pressure and negatively affect cholesterol.

Results

Women who want to use this cycle for gaining lean muscle can (with the proper training and diet) find gains of 15lbs possible – while also burning fat.

Males can expect significant fat loss with this stack and even some moderate muscle gains. Your training and diet will determine how much fat you can lose, but if you’re already lean, you could burn off 10 lbs or more. If you’re not in great shape, it’s more than possible you could drop 20lbs, 30lbs, or even more – depending on how much body fat you have to lose.

PCT

Not sure if you should do PCT after this stack? Get your bloodwork done! As I’ve said many times, it’s simply the best way to know where you’re at with testosterone suppression. Women will not need PCT after this (or any other) stack.

Total testosterone can drop quite substantially after this stack; while it will recover on its own, it can take a few weeks. A standard Nolvadex or Clomid PCT of 20mg/day for four weeks will speed up testosterone recovery.

Ostarine + Ibutamoren (Bulking Stack)

Ostarine is an excellent bulking cycle base and you can use it with a range of other compounds to gain muscle, but here, I want to focus on Ibutamoren. This is a stack that appeals to beginners and intermediate users, and I’ve had superb results with this simple but still potent and synergistic combo.

Benefits

• Increased appetite
• Faster recovery
• Increased IGF-1 levels

Dosing

You can run this for 12 weeks, but I prefer a hard and fast 8-week cycle, followed by PCT. Keep it simple: 20mg/day of Ostarine and 15mg/day of Ibutamoren does the job.

Possible side effects

• Water retention
• Increased prolactin
• Elevated blood sugar
• Lethargy

Results

I felt the appetite increase early on, making it easier to consume more calories, which contributed to more significant gains. Just make sure you’re eating the RIGHT type of calories.

Ibutamoren also helps preserve muscle like Ostarine does, but combined, it will help maximize the muscle gains that Ostarine can provide and build upon them. Gains won’t be steroid-like but in the realm of 15 lbs with proper training.

Notably, the gains are maintainable as long as you keep Ibutamoren’s water retention potential to a low level by keeping to a low sodium diet and drinking plenty of water.

PCT

Tamoxifen for four weeks (starting at week 9). 20mg/day for the first three weeks, dropped to 10mg/day for the final week.

Ostarine + Ligandrol + RAD-140 (Recomp Stack)

A recomp stack like this is all about burning fat and building muscle at the same time. This is a challenging goal and one for more advanced users, but this stack, combined with a high protein, balanced diet, and plenty of water, can reshape your body in 10 weeks. A high-intensity cardio training regime, combined with weight lifting, will bring about phenomenal results.

Benefits

• Reduce overall body fat percentage
• Build lean muscle
• Increased muscle definition
• Ostarine acts as an anti-catabolic agent to prevent muscle loss
• Boost to energy and confidence

Dosing

For best results, taper the dosage of each compound throughout the cycle:

• Weeks 1-4: 10mg Ostarine, 10mg Ligandrol, 10mg RAD-140
• Weeks 5-8: 15mg Ostarine, 10mg Ligandrol, 15mg RAD-140
• Weeks 9-10: 25mg Ostarine, 20mg Ligandrol, 20mg RAD-140

Possible side effects

• Hair loss (Ligandrol)
• Testosterone suppression
• Liver toxicity (highest risk is from RAD-140)
• Elevated blood pressure
• Testicular pain and joint pain (Ostarine)

Results

Ligandrol and RAD-140 combine to help you bulk up on this cycle, but as a recomp cycle, it’s also about losing fat at the same time.

Ostarine is the basis for maintaining muscle gains here and with the correct diet and training, expect a notable drop in body fat around the abdominal area. Increased muscle definition follows, thanks to the reduction in subcutaneous fat.

The amount of lean mass you can and will gain is entirely up to your effort – 15 lbs of quality gains are achievable with this stack.

PCT

Most guys will want to do PCT after this stack, with both RAD-140 and Ligandrol considered mildly suppressive SARMs. Tamoxifen or Enclomiphene are the best PCT options. I prefer Enclomiphene after this stack and for four weeks. 12.5mg daily of Enclomiphene for the first three weeks, then 6.25mg of Enclomiphene daily for the final week.

Ostarine PCT

I’ve seen opposing views on whether guys (and specifically its male users, females never need PCT) should do PCT after an Ostarine cycle. But I want to make it as simple as possible by having you consider these two things:

• Whether you’re using Ostarine on its own or stacked with any other PEDs
• What does your bloodwork look like post-cycle? (You have thought about doing bloodwork, right?)

In other words, whether you should do PCT after using Ostarine depends on your situation. There’s no right yes or no answer here.

Ostarine is a milder SARM in terms of suppression, and you can get away with no PCT if your bloodwork is good and you’ve only done a shorter cycle at low to moderate doses. What if you’ve done bloodwork and need to decide whether to PCT? Check out these two primary biomarkers:

• LH (luteinizing hormone)
• FSH (follicle-stimulating hormone)

The results will give you the best indication of whether PCT is required because the levels of those two hormones will tell you how suppressed your natural testosterone is.

Natural Products for PCT

I also want to mention some of the talks around using natural products like herbal remedies for PCT (think things like Tribulus and Ashwagandha).

While they might have some health benefits elsewhere, they’re not going to be powerful enough to raise your LH and FSH levels after being suppressed. So don’t use them for PCT.

Aromatase Inhibitors vs. SERMs

So what about AIs (aromatase inhibitors) for PCT? They stimulate testosterone production, so they are useful PCT compounds in some cases. However, because of the way SARMs like Ostarine work (not aromatizing to estrogen), your already low estrogen levels will crash to nothing if you use an AI.

So, an AI is not the ideal choice for an Ostarine PCT unless you’re also using a compound that causes estrogenic side effects (like some steroids).

SERMs are the better choice for Ostarine PCT and will be effective at raising your LH and FSH, stimulating testosterone production. Nolvadex, Clomiphene, and Enclomiphene are three common PCT choices.

So, while you don’t HAVE to have bloodwork done, you’re essentially running blind if you don’t, and you’ll need to decide whether or not to do PCT based solely on how you feel rather than by looking at your biomarkers throughout and at the end of your cycle.

Ostarine During PCT

So why would you consider taking Ostarine during PCT? I’ve read about some guys using Ostarine as part of a PCT protocol because they think it will help protect muscle gains and maintain energy while your testosterone is low after a steroid cycle. While Ostarine definitely is anti-catabolic, it can also suppress testosterone (not as much as steroids) at higher doses.

If you find a low Ostarine dose (20mg or less) helps with recovery and maintaining gains, it could be helpful for PCT. However, most steroid users will find the traditional PCT SERMs and HCG methods to be far more effective.

Bridging with Ostarine

As far as bridging with Ostarine in between anabolic steroid cycles – I don’t recommend it. In my opinion, it’s just going to cause more HPTA suppression at a time when you’re trying to recover.

If you’re an advanced user, you could (theoretically) use Ostarine to bridge on a blast, cruise, and TRT basis, but this can get complex and isn’t particularly healthy or valuable. In short? Don’t bother using Ostarine for bridging; I wouldn’t use it for PCT, too.

Ostarine Side Effects

Although I’m going to list below quite a few POSSIBLE side effects of Ostarine, I don’t want you to be alarmed. Ostarine is now well known as being a well-tolerated SARM by the majority of users – and that’s both men and women.

Yeah, as with anything, a small number of people will experience some adverse effects. But even in those cases, sides are likely to be mild and manageable. Here’s the must-know info for the potential side effects of Ostarine for both men and women:

Ostarine side effects (Men)

• Testosterone suppression (usually mild to moderate, depending on dosage and length of use)
• Testicle shrinkage or pain
• Erection issues
• Fatigue or low-energy
• Acne
• Headaches
• Hair shedding
• Reduced HDL cholesterol levels
• Liver toxicity at higher doses

Ostarine side effects (Women)

• Reduced HDL cholesterol
• Headaches, fatigue
• Liver toxicity at higher doses
• Changes to libido

And I’ll say this about any compound, heck, any drug at all, including over-the-counter painkillers. Use Ostarine sensibly and within the recommended dosage and cycle lengths; you’re unlikely to have any issues.

Where to Buy Ostarine?

Have you thought about where you might buy Ostarine once you’ve decided to run a cycle? I recommend starting your research now and not jumping into the first source you find. I’ve experienced the good and the bad, as well as middle-of-the-road quality Ostarine.

The difference between the best and worst stuff is like night and day. It is worth your time and money to find the BEST possible trusted source to buy your Ostarine every single time you use it.

So, where to buy it? Here are my top picks:

Availability of Ostarine

Like all SARMs, Ostarine is sold as a research chemical only. Technically, it should only ever be sold to and used by legitimate scientific researchers. But you can consider this a very gray area, and as you’ve probably learned by now, just about anyone can quickly get their hands on Ostarine online. This is both good and bad!

It’s great that we can pretty much buy Ostarine without looking over our shoulders like we do with steroids. But on the downside, this ease of buying and selling and lack of regulation of research chemicals means there are sketchy labs and suppliers. It’s on you to do your research and find a quality source of Ostarine.

Is Ostarine Legal?

Ostarine has no FDA approval for any medical use and will likely never have it. So, there is no official pharmaceutical production of Ostarine; technically, buying is not legal unless you’re a scientific researcher.

But Ostarine is still yet to be regulated in the same way that anabolic steroids are, so acquiring SARMs like this is relatively straightforward and low risk from a legal perspective. In my own experience, I’ve had zero legal issues with buying Ostarine and using it.

But if you’re a competitor where drug testing is a possibility? Ostarine falls under the same prohibited substance list as anabolic steroids and other PEDs, so it can not be legally used in competitions or other events where anti-doping policies apply.

Typical Pricing

I can not stress enough the importance of finding a quality source of Ostarine. Want to go cheap? Just wasting your time and money.

Why?

Because the product is not going to be high-purity Ostarine, any expectations of results go out the window. And you can find side effects pop up that you never knew existed.

That’s not to say higher-priced Ostarine is perfect – nothing stops a seller from pricing high to give the impression of a quality product. You gotta verify suppliers with people or sources that you trust.

Now, there are going to be factors that contribute to the prices you come across for Ostarine. Things like:

• The manufacturer and their reputation
• Dosing or concentration strength
• Country

The good news is that bad manufacturers and suppliers soon go out of business once word gets around, but that doesn’t stop new ones from popping up, so you can’t afford to let your guard down when buying Ostarine.

So what can you expect to pay for good quality Ostarine?

Mostly, you’ll find it sold in bottles of 30ml liquid at a concentration of 20mg/ml, 25mg/ml, 33mg/ml, and even up to 50mg/ml, so pay close attention to the concentration because you’ll need it to formulate your dosing. Pricing anywhere from $70 up to $150 can be found from online research labs, depending on the location.

Final Thoughts

Ostarine is one of my favorite SARMs. And it’s not just me either because this is one of the most popular SARMs in use today! So, it must be doing something right for a lot of people.

The fact that it’s still one of the most thoroughly researched SARMs is a nice bonus – we know it can work when used right. We also haven’t seen any hugely worrying side effects in any studies or real-world performance use.

Ostarine has a lot of trust in the performance community, and I use it confidently, but whether it’s right for you is a decision only you can make! I hope you’ve learned a few more things about Ostarine here. Thanks for reading!

Related:

• RAD-140 SARM 101: The How-To Guide to Testolone
• SR9009 SARM 101: The How-To Guide to Stenabolic
• Cardarine SARM 101: The How-To Guide to GW-501516

— Furious Joe