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Ostarine (Mk-2866) Review: Effects, Ostarine Dosage & Where To Buy

Ostarine (MK-2866) is the original SARM (Selective Androgen Receptor Modulator). In this quick guide, you’re going to learn everything you need to know, including the correct Ostarine dosage range and effects you can expect from your first cycle.

We will talk in detail about the effects Ostarine can produce, and how it can be used productively both during a SARMs cycle and sometimes even during PCT (post cycle therapy).

You’ll also learn about the truth behind those Ostarine before and after photos and reviews because there are a lot of scams out there. Plus, we will discuss how you can spot online sellers who sell guaranteed pure SARMs.

What Is SARM Ostarine?

Ostarine, also known as Enobosarm, GTX024, and MK-2866, is the original SARM. It’s also informally known in the bodybuilding community as Ostamuscle (often just “Osta”).

It was developed by a company called GTx from 1997 onwards, reaching the level of phase II human trials in 2007. However, things have stalled since then.

Designed for muscle-wasting conditions like osteoporosis, its mechanism of action is still actually not fully understood. Additional trials up until 2018 on humans have looked into Ostarine being used for a variety of conditions, but so far not been found successful for anything other than preserving muscle stop

So it’s important to say here at the start of this Ostarine review that it has never been authorized for use by humans. It’s been in trials with humans, but it’s not commercially available, and certainly not for use by bodybuilders to preserve lean muscle mass while cutting fat. However, it’s one of the few SARMs which has been through pretty extensive initial human trials, with no dramatic side effects ever noted.

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How Ostarine MK-2866 Works

Ostarine is a Selective Androgen Receptor Modulator. It literally does what it says, it selectively binds to androgen receptors and modulates their responses.

But it does it selectively, unlike anabolic steroids which hammer androgen receptors with messages all around the body. SARMs like Ostarine can target androgen receptors in bone and muscles specifically.

So it’s this selective nature that is so appealing. It means that SARMs like Ostarine do not have the dangerous side effects that anabolic steroids do.

Ostarine Benefits For Bodybuilding

Because Ostarine was created to preserve muscle mass in people who have muscle wasting diseases, bodybuilders assume that Ostarine is only good for preserving muscle while you cut body fat during a cutting or recomping phase.

But that’s not actually the whole story about MK-2866. The full range of Ostarine benefits you can experience are:

  1. Although it’s not a potent muscle builder, a lot of people don’t realize that Ostarine can actually help to build muscle. It will always preserve your muscle, even in a calorie deficit. But alongside great diet and a gym routine that pushes you harder, it can actually build muscle faster and leaner than you can naturally. It just won’t be as noticeable as with more aggressive anabolic SARMs like Andarine.
  2. You will burn fat faster using Ostarine MK-2866. Because it can preserve muscle mass it preserves strength in a calorie deficit. This means you can fuel yourself enough to push through your routines, but you’ll also be cutting fat dramatically. It’s possible to cut 5% of your body mass in a single cycle and not lose any muscle mass using Ostarine.
  3. Because Ostarine is very mild it’s possible to use it after a SARMs cycle as well. So you could use a more aggressive SARM to build muscle on cycle, and then use small doses of Ostarine post cycle to preserve your gains.
  4. Ostarine produces results with very little testosterone drop. So it’s a perfect beginner’s SARM, and it’s great for people who already struggle with their testosterone levels.

Ostarine Dosage Guide

Let’s now talk about the sort of Ostarine dosage range you should be using to get the benefits of this very mild SARM.

During the SARMs cycle, if you’re cycling just Ostarine, then a ceiling of 40 mg per day is sensible. Above this effects seem to diminish, and you stand more chances of getting testosterone suppression.

A lot of people dose low at the start of a cycle, especially the first cycle, and increase the dose either during that first cycle or in the second cycle.

But on its own, an Ostarine dosage of up to 40 mg per day is absolutely fine. If you’re wanting to put on bulk as well as cut then you’re looking at that higher level dose. But if you just want to cut fat then 20mg is often more than enough.

Below about 20 mg per day effects can be very mild because Ostarine is a mild selective androgen receptor modulator.

You only need to dose Ostarine once per day because its half-life is quite long. Some SARMs require twice-daily dosing, but that’s not the case with Ostarine which makes it even easier to use.

Ostarine Dosage

Cycling & Stacking Ostarine

For your first Ostarine cycle, you should be conservative with your dosing and duration. You need to make sure that your body doesn’t have negative side effects from strong testosterone drop, although that’s unlikely using this mild SARM.

For me, I’d advise your first Ostarine cycle should look like this:

  • Dose Ostarine at 15 mg for the first two weeks
  • Increase Ostarine dosage to 20 mg in weeks three and four
  • Increase dosage of Ostarine to 30 mg in weeks 5-8
  • First cycle should be eight weeks (subsequent cycles can be pushed to 12 weeks easily)
  • PCT supplement may be required (but this is unusual)

If you’re looking to stack SARMs then Ostarine is great for cutting fat and maintaining muscle during a cutting or recomping phase.

Just make sure that when you stack Ostarine that you keep the dose lower. You have to remember that it is anabolic in nature and stacked with other anabolic SARMs those combined doses can be quite high and suppress testosterone significantly.

I’ll also mention here that you can use Ostarine post cycle. Because it’s only mildly suppressive, a small dose of around 15 mg during PCT can help to preserve your gains better with no effect on the PCT supplement’s ability to restore testosterone drop.

Ostarine Results From One Cycle

So let’s talk about the results you can get from a single cycle of Osta. Let’s say you dose 30 mg daily over eight weeks, what can you expect?

Well, I think it’s important to say here your results will depend on how hard you push yourself. SARMs aren’t magical like anabolic steroids, you have to do resistance training for them to get to work on your muscles in terms of growing them and hardening during muscle repair.

But a single cycle of Ostarine combined with great gym work and a non-fat diet can produce the following results:

  1. In a single cycle you can lose up to 5% body fat realistically. This doesn’t sound much but it’s actually a very significant amount of body fat to lose. You will only lose this if you work hard and have a superb diet.
  2. MK-2866 Ostarine will definitely preserve muscle mass. As your muscles repair, even in a calorie deficit, Ostarine will stop your body using them for fuel.
  3. Ostarine can also build muscle. Not much, but definitely your gains will be faster and harder than you can achieve naturally.
  4. After a single cycle of Ostarine, backed up by great diet and gym work, you can lose body fat, gain definition, and even build muscle.

Ostarine Results

Ostarine Before And After Photo & Reviews

I just want to get real with you guys here and talk about those Ostarine before and after pictures that you will see online.

This is an Ostarine review, but I’m trying to be honest with you about its limitations. But compare this to those reviews of Ostarine out there where you get lots of dodgy before and after photos of guys who are really weedy, and then after a single cycle, it’s claimed that they lose all their body fat and gain muscle.

This simply isn’t true. They are often generic stock photos, or they are guys who have done loads of cycles of different SARMs, or they are using steroids as well.

At best you’re seeing someone who has had an extreme response, at worst you’re being scammed.

The truth is that all SARMs require hard work and a great diet. If you combine this with Ostarine though, in a single cycle I’m telling you that you will cut Nipper can fat, preserve muscle, and even gain muscle in a way that you simply can’t naturally.

Ostarine Side Effects

 Because Osta is so mild you won’t really get any side effects if you’re being sensible with your dosing. People talk about feeling tired with Ostarine. But that’s actually testosterone drop. Because they don’t expect it to happen, they don’t realize that what is causing it.

So although it’s unusual, Ostarine, especially at higher doses, can cause some testosterone drop. If you haven’t got high testosterone levels, then you’re obviously going to feel it more.

It’s the mildest SARM though, and you shouldn’t really have any other side effects apart from the potential for minor T level drops.

So always have a PCT supplement to hand. Nolvadex will be absolutely fine, and you’ll be able to take small doses of it should you need to. But for most people, you won’t get any side effects, and there won’t be any testosterone drop so you could use Ostarine even between cycles of other SARMs.

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Where To Buy Ostarine Mk-2866

So now you understand the Ostarine dosage range should be using, the effects you can gain, problems you could face from using Ostarine, and you know the truth about those Ostarine before and after photos, let’s tell you where you can buy 100% pure SARMs.

Because they are only research chemicals and aren’t legally available, it’s tough to get pure SARMs that are safe. You’re looking for online stores that offer independent third-party lab testing, with the results published on the product pages.

These are where I have bought SARMs, and they are all highly recommended SARMs sellers. Any one of them will be a great starting point for experimenting with Ostarine.

1. Swiss Chems

Swiss Chems are a company that I have bought SARMs from (infrequently) for several years now.

I used to buy from them a lot when they sold SARMs liquid. Then I switched to Science.bio for most of my SARMs because of the difference in price between liquid in capsules at the time.

However, for reasons unclear to me, the prices of the capsules Swiss Chems make have dropped dramatically in the past 12 months, not that I’m going to complain about that. They are at the point now where there’s not actually much difference between the price of liquid in capsules.

Plus, purity and quality are vital to me, as they should be for you. Swiss Chems offer current lab testing and have fantastic feedback online. Also, I know for many years using them, that the SARMs they sell deliver results without side effects. Swiss Chems sell nine different types of SARMs, all the ones you would expect to be able to buy to create bulking and cutting stacks.

Pricing for capsules is now excellent. Let’s look at Ostarine specifically.

60 capsules of Ostarine, each dosed at 10 mg per capsule, costs just $63.95 at the time of writing this.

That’s only five dollars more than comparable high-quality Ostarine liquid. So for just five dollars, you’re getting the convenience of exact dosing, not dealing with the taste of SARMs or suspended liquid, and being able to take these on the go.

Overall, Swiss Chems have stepped into the breach and are offering high-quality SARMs at prices that are really surprising for the convenience of capsules.

Plus, they also sell generic Nolvadex and Clomid in capsule format, along with peptides, and even now some nootropics. They are becoming a one-stop-shop for all types of grey market supplements.

Swiss Chems 10% discount code: gyula10

2. Chemyo

Chemyo is 100% the highest quality liquid SARMs seller still running in the USA right now.

The past 18 months have seen the SARMs sellers in the USA decimated. There are several reasons for this, including the pandemic, Eastern European lab shutting down, the Chinese SARMs manufacture ban, increasing regulatory scrutiny, and FDA attention.

Put all that together, and it’s left only a handful of reputable SARMs sellers still standing. That’s obviously a problem, and it’s why I know recommend that you get at least your next three stacks in stock right now.

Don’t delay, don’t procrastinate. If you’ve got the money, plan your next three stacks (basically your next years worth of bodybuilding) and buy them now, before it’s too late.

Chemyo has a lot going for them:

  • They sell all the top SARMs
  • They offer raw powder SARMs at cheap prices as well
  • Full moneyback guarantee
  • Free domestic shipping over $100
  • Large 50 mL dropper bottles
  • Purity guaranteed through independent lab reports

Put all that together, and you’ve got one hell of a SARMs seller. In fact, looking at all the quality they offer, it’s almost like a dream in the current environment where you are scrapping around looking for quality.

Let’s now talk specifically about Ostarine.

You can buy a 50 ml dropper bottle of Ostarine for just $59.99. It’s dosed at 25 mg/mL as well, which is a really strong dose and bottle size for the price.

You can also buy Ostarine as part of the pair, with a discount. Ostarine is paired with Cardarine and also paired with MK-677.

I’m a bit confused as to why they have paired it with MK-677, is that work by increasing growth hormone activity and also increases appetite. It’s a bulking compound, I don’t quite get why it’s been paired with Ostarine, which is almost always used as part of the cup.

Anyway, the quality is really good, and they are now the only people I buy my SARMs from.

Chemyo 10% discount code: ihcc10

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SARMs Alternatives

The truth is that there aren’t many alternatives to SARMs other than steroids and peptides. Many of the peptides aren’t as potent as SARMs, and right now, supplies of those are drying up in exactly the same way as they are SARMs.

You don’t want to be touching steroids, which leaves you either scrapping around looking for SARMs or doing natural bodybuilding.

For me though, there is another alternative. Not just natural supplements, but SARMs mimicking supplements.

Crazybulk of creating a range of completely natural supplements that mimic the effects of SARMs.

Now, let me be upfront here and tell you that they aren’t as potent as SARMs. If they were, nobody would be messing around with SARMs. But, they do offer an alternative if you don’t want to use SARMs, or you can’t get your hands on them right now.

Also, another benefit is that you can run them alongside SARMs. Because there are no side effects or issues, there’s no reason not to. They will help to emphasize even further the results that you get.

Plus, you can run them post cycle. Why not? People run Ostarine, so why not remove all the risk by running a stack of natural SARMs alternatives instead?

Talking specifically about Ostarine, they have a supplement called OSTA2866 that mimics its results, namely:

  • Increased energy and stamina
  • Faster fat cutting
  • Muscle protection
  • Muscle hardening and gains

On its own, you’ll pay $69.99 for a month’s supply. However, they also have a buy two get one free deal, so you can get 12 weeks (enough for SARMs cycle and PCT) for just $120. To save even more, and get more potency, I’d run them as a stack. The three supplement stack that includes OSTA2866, and the Bulkin stack, costs just $209.99 for a month’s supply.

Again, you’ll get the third month free as well. That will allow you to run not only a cycle but also run it through PCT for additional benefits.

natural ostarine alternative


2. Rats Army Now Out Of Business

Rats Army is a SARMs seller who excites me. They are one of the first companies I’ve heard selling SARMs made in the USA. The other was the now-defunct “proven peptides”, so they picked up on a niche that will only grow and has no rival.

SARMs are mostly made in China, but a ban a year ago has meant supplies are drying up in the USA and around the world. Rats Army supplying SARMs made in the USA obviously is great news for anyone using SARMs.

Talking specifically about Ostarine, a standard 30 mL dropper bottle, dosed at 25 mg/mL, will cost you $53.99. They even sell SARMs in six different flavors, rather than just unflavored. So if you want some taste when you take your liquid SARMs, this company is offering that difference as well.

3. Science.bio

Science.bio went out of business at the end of March 2022. This is devastating as they were one of the most high quality and reliable SARMs sellers in the USA for many years. I’m now recommending Swiss Chems as the number one choice, due to the high quality of the SARMs they sell and the convenience of the capsule format.

These guys have been around a long time. They rebranded recently because they started selling more than just SARMs, they now sell tons of other supporting supplements.

Let’s talk about Ostarine though. They sell loose powder and liquid Ostarine. I’d always advise against loose powder though because it’s a pain to deal with. But it is dirt cheap, costing just $30 for 1000 mg.

In terms of Ostarine liquid, 900 mg of Ostarine (concentration 30 mg/mL) retails at $79.99. This is a good price, and every independent third-party batch report is published on the product page.

4. Proven Peptides – CLOSED

Proven Peptides are different because the SARMs they sell are made for them in the USA rather than China. China has actually stopped producing SARMs now so you’ll see more and more companies moving over to the higher grade and safer USA SARMs soon.

Ostarine from Proven Peptides costs $79.99 for a 30 mL dropper bottle. It’s dosed at 25 mg/mL, with a total dosage in the bottle of 750 mg.


Last on my list of SARMs sellers, concluding this Ostarine review, are SARMs 4 You. I put them on the list because they are based in Europe, so great for you guys outside the USA. I did a test order six months ago though and it arrived fine and the SARMs worked brilliantly.

In terms of Ostarine pricing, they sell both loose powder and capsules SARMs. 60 capsules, each with an Ostarine dose of 10 mg, will cost you $55. So cheaper capsules than Swiss Chems. You have to spend more than $120 to get free global shipping though. However, if you can spend that much then it can actually work out really cost-effective even if you’re in the USA.

UPDATE: SARMs4you and ProvenPeptides are out of business.

Frequently Asked Questions

What does Ostarine do to the body?

Ostarine was originally designed to deal with muscle wasting illnesses and brittle bone problems. It targets androgen receptors in muscle and bone tissue, telling them to grow harder and denser. So your muscles will be denser in growth, and your bone strength will increase. On top of that, Ostarine tells the body to burn fat before it burns muscle tissue, utilizing glucose and fat to protect your muscle mass in a calorie deficit, and slightly increase your overall energy budget to spend.

Does Ostarine raise testosterone?

Ostarine does not raise your levels of testosterone. Androgenic SARMs work by mimicking the messages that testosterone hormones send to muscle and bone tissue. In fact, it works the opposite way. Your body then thinks it’s got more testosterone and it actually has, so it starts to cut back on its own production. So no, Ostarine and androgenic SARMs do not raise testosterone levels, they actually cause the body to deplete them.

Do you have to stack Ostarine?

You certainly do not have to stack Ostarine. It’s very mild and can use off-cycle as well as on. On its own as a single SARM cycle, it will protect your gains, cut more fat, and deliver more energy than can be delivered naturally. It’s very good because it’s mild, and anyone can use it to achieve more than they could naturally. But as with all SARMs, you get more potency from stacking Ostarine with complimentary SARMs such as Andarine and Cardarine.

Can you bulk on Ostarine?

Ostarine is not hugely androgenic, nor does it increase muscle mass by any other interaction. Therefore, Ostarine is not good for bulking. Even at high doses, you will not improve your muscle mass. You may improve the hardness and dryness of your muscle slightly, but you will not increase bulk. To bulk, you need SARMs like Ligandrol, Testolone, YK-11, and MK-677.

Is Ostarine a steroid?

Ostarine, just like all androgenic SARMs, is nonsteroidal. That’s what makes SARMs safer than anabolic steroids. Androgenic SARMs mimic testosterone, but only through targeting androgen receptors in muscle and bone tissue. Therefore, SARMs like Ostarine do not work in the same way as steroids at all, nor have steroidal effects in the body.

Is Ostarine a fat burner?

Ostarine definitely is a fat burner. It works in the body by telling it to burn fat in preference to glucose. Even in a significant calorie deficit, your body will burn fat in preference to muscle tissue, which can be burned early if there is excessive tissue. Generally, Ostarine is a good fat burner, and you will definitely burn more fat can using your own natural bodybuilding energy alone. Stacked with Cardarine, which increases the body’s energy output, and you will work out harder and longer, burning even more energy, alongside the fat burning, to deliver a significant cut.

How much muscle can you gain from Ostarine?

Unfortunately, you will not pack on lean muscle using Ostarine. Although it androgenic, it’s very mild, and even at a high dose of around 50 mg per day you will not pack on muscle. You will dry your muscles out, and harden them, and you will protect them in a calorie deficit, but you cannot put on any lean muscle mass with Ostarine. Ostarine is perfect for protecting muscle gains in a cut, and telling the body to burn fat supplies in preference to glucose, enhancing your fat loss. If you want to increase your muscle mass, you should be looking at using SARMs like RAD-140, YK-11, LGD-4033, or MK-677.

Does Ostarine have side effects?

As long as you are sensible with your dosing, then Ostarine does not have any side effects. It’s mildly androgenic, but at doses of 40 mg or less, you are unlikely to suffer from testosterone drop. If you keep your dose below 40 mg, then you should only experience benefits using cycles of Ostarine. Just make sure you keep a good gap between each cycles. Should you suffer any testosterone drop using high doses of Ostarine, it will be incredibly mild, and can easily be rectified with a natural testosterone boosting supplement.


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