Andarine (S4) VS Ostarine (MK2866)

A lot of people want to learn more about Andarine S4 vs Ostarine MK2866 as these are two popular SARMs that are offering similar benefits, both are popular for cutting cycles and they are even similar structurally.

These two SARMs are actually pretty similar to each other. Andarine (S4) was abandoned in clinical trials in the favor of Ostarine (MK2866). That’s because Ostarine has a better safety profile than Andarine. Despite this, a lot of bodybuilders and athletes are still using Andarine nowadays. And of course, MK-2866 is a popular compound in bodybuilding.

Bodybuilders are usually using those compounds that are offering great results for their physique and performance enhancement needs. With this being said, let’s take a look at these two SARMs. In this article, you’re going to find valuable information and a side by side comparison.

Andarine S4

s4-andarineAndarine S4 is a stronger SARM in comparison to Ostarine MK 2866 when talking about muscle building and bone health improving potential. Or at least, that’s what it seems like from the studies on animals and anecdotal reports from those who already tried both of these compounds.

Andarine was actually extremely promising thanks to its high bioavailability, great tolerability as well as strong affinity to the androgen receptor. Nonetheless, it was abandoned later because scientists revealed that Andarine causes impaired vision in those who use higher dosages.

Check more information about Andarine S4 here.


Ostarine MK2866

ostarine-mk-2866Ostarine MK-2866 is the most studied SARM on the market. This is one of the main reasons why it also seems like the most popular SARM out there too. Interestingly enough, MK 2866 is offering similar effects to those of S4 SARM, however, without the side effects of vision impairment.

Ostarine is one of the most researched steroids on the market because studies prove it to be relatively safe to use. Most people seem to tolerate it extremely well. People who already experimented with it suggest the same, saying that it’s relatively mild and safe. Yet, it definitely doesn’t mean that Ostarine doesn’t come with its own disadvantages and side effects. But at least, MK2866 is still in the clinical trials, reaching human tests.

You can check more information about Ostarine MK2866 here.


Andarine vs Ostarine Half-Life

Ostarine half-life is much longer than the half life of Andarine, and for this reason, it’s much easier to dose it.

  • For example, Ostarine half-life is 24 hours. That’s why it only requires dosing once a day.
  • On the other hand, Andarine half-life is only 4 hours. For this reason, you need to use it multiple times a day.

It’s very important to learn about half life because it offers an idea of how to correctly run a specific product. This is going to maintain stable levels of it in the blood (without highs and lows) and that’s what offers maximum results.

Andarine vs Ostarine Benefits

When comparing the benefits of S4 vs MK2866, it seems to me that S4 (Andarine) is a better product. But before actually making a conclusion that S4 SARM is better, I strongly recommend you read this post until the end.

Below I’m going to offer a comparison for both of these SARMs in terms of benefits. Moreover, I personally used both of them, that’s why I’m going to talk about my experiences with them. Yet, it’s very important to remember that everyone is different and experiences can be very different for different people with different compounds!


Muscle Mass

Both Ostarine and Andarine are SARMs that are doing a great job in preserving lean muscle tissue during a cutting cycle.

In fact, I can tell you from my own experience that there’s not a huge difference between the two in terms of muscle mass gains. I managed to gain lean muscle tissues while remaining on a caloric deficit diet with both of these SARMs. Yet, Andarine seems a tad better.

I gained around 2-3 pounds of lean muscle tissues with Ostarine and around 3-4 pounds of lean muscle tissues with Andarine. There’s not a huge difference, but still somewhat.

  • PS: It’s extremely important to note that muscle gain (and fat loss) is very tightly connected with your genetics and especially your diet and training routine. Without a proper diet and workout plan, you just can’t expect to gain muscle and/or lose fat.

Fat Loss

When it comes to fat loss and vascularity, I found Andarine somewhat a superior SARM over Ostarine too. It’s either because I lost more actual fat while on Andarine (same diet and workout plan) than on Ostarine or because it helped me dry out more, but I was looking leaner and more shredded on it.

I can’t say that there’s a huge difference when it comes to fat loss and vascularity either, but I was still noticing some more and better results while I was on S4 than on MK2866. Both are great, but Andarine for fat loss seems better.


You can’t compare these SARMs with actual bulking SARMs when it comes to muscle gains or strength increases. Nonetheless, both of these SARMs will help you grow muscle and become stronger. You will only get slightly stronger on them, but the difference is still noticeable.

  • PS: It’s important to understand that you may not become as strong on these SARMs because most people use them for cutting cycles. This means they are in a caloric deficit which definitely has a negative impact on strength.

Yet, although remaining in a caloric deficit, you can still increase strength, rather than lose it without them.

I would say that when it comes to strength gains, they are pretty much close to a tie. However, I would still think that S4 Andarine is just a little bit better in this department than MK2866 Ostarine.

Andarine vs Ostarine Side Effects

As you can notice, when comparing these two SARMs only by checking the benefits, Andarine seems better than Ostarine. However, unfortunately, SARMs are also capable of causing side effects. It’s equally as important (if not even more important) to check the side effects of a compound too, before actually using it.

When comparing MK 2866 and S4 in terms of side effects we have another winner. MK-2866 seems actually a better compound because it’s milder and safer. Remember that the higher safety profile of MK2866 is what made scientists give up on S4 SARM and focus on Mk2866 more.


Testosterone Suppression

Many people tend to believe that SARMs are not suppressive at all and that’s a huge mistake. Another popular belief is that Andarine or especially Ostarine does not cause natural testosterone suppression in our bodies. Well, that’s another big mistake.

They are not the strongest SARMs out there so the suppression rate isn’t going to be as high as with other more powerful SARMs. Nonetheless, being mild doesn’t mean that it’s all safe or that it doesn’t cause suppression. They both actually can. That’s why it is very important to watch out for the dosages and/or cycle lengths that you plan to use.

Obviously, the larger the dosage and/or the longer the cycle length – the heavier the suppression is going to be. Yet, judging which one is more suppressive out of S4 Andarine and MK2866 Ostarine, I would say that Andarine is capable of suppressing you more. Given the exact same cycle length and moderate dosages of both. It’s a bit stronger so that is quite obvious.

Liver Toxicity

SARMs are oral compounds (either you use them in liquid or pill form) and they are a little bit hepatotoxic. The hepatotoxicity level differs from one SARM to another but it’s still worth knowing that the liver goes through some stress during SARMs cycles.

When comparing the liver toxicity of MK2866 and S4, I would also call it a very close tie. But since Ostarine is overall milder, it does seem like Andarine is a little bit more liver toxic than Ostarine.

In normal circumstances though, you shouldn’t develop any liver issues at all. That’s assuming that you are healthy enough (healthy liver), do not abuse either one in terms of dosage and/or cycle length and add liver protecting supplements during the SARMs cycle.

Impaired Vision

Impaired vision is the most popular side effect of Andarine S4. This is the reason why scientists gave up on researching S4 any further. That’s in the time that Ostarine doesn’t have this side effect at all, not even at higher dosages.

While this side effect is not occurring to everyone and it usually only occurs in higher dosages, it’s still worth mentioning that while running Andarine you can experience it, and some say that this side effect can be serious.

Those people who are using too much Andarine (too high dosage and/or for prolonged periods) or those who are susceptible to this particular side effect (or especially a combination of both) might experience impaired vision. It may result in a yellow tint in their peripheral area and/or decreased night vision.

Either because I always was conservative with Andarine dosage, or because I’m not very susceptible to vision issues (or maybe both) but luckily enough I didn’t experience this issue. But it’s very important to remember that because I haven’t experienced it – doesn’t mean you won’t. Lots of guys out there using it report they experience vision issues while on the Andarine S4 cycle.

Andarine vs Ostarine Results

In the end, as I said, both of these SARMs are offering similar results. That’s when talking both about benefits and side effects. However, they are still different.

I already mentioned earlier that Andarine is somewhat stronger than Ostarine. Both scientists and anecdotal evidence from athletes and bodybuilders prove it. This is the exact reason why you’re more likely to experience both more benefits and side effects on Andarine than on Ostarine.

  • For example, on a common Ostarine cycle you’re about to lose 2-3% of body fat and add about 3-4 pounds of lean muscle with fairly tolerable side effects.
  • On the other hand, a common Andarine cycle is also going to offer fairly tolerable side effects, but it comes with the unwanted side effect of impaired vision. Yet, it helps you burn a bit more fat and add a bit more muscle. ostarine-vs-andarine

Andarine vs Ostarine Prices







Before we compare the prices, remember that there are different common daily dosages for each of these compounds. For example, a common Andarine S4 dosage is 25-75 mg/day. But Ostarine MK2866 dosage is 10-30 mg/day.

It’s safe to say that buying a total amount of Andarine 1000 mg is almost the same as buying a total amount of Ostarine only 500 mg because of the dosage difference.

By following this idea, it’s clear to see that they are about pretty much the same price, but Ostarine still seems to be a bit cheaper.

Remember that the price highly depends on the manufacturer too. But by comparing the prices for these two SARMs from different manufacturers, it seems like MK2866 is a bit more affordable. The difference is actually not really considerable, but if you’re in a cash crunch then MK 2866 does seem like a somewhat better idea.

That’s because Ostarine is a little bit more budget friendly option. After all, Ostarine MK-2866 is also a more side effects friendly option so saving money and experiencing fewer side effects doesn’t sound like a bad idea at all.


In the end, from everything that I mentioned above, we can draw a conclusion.

That’s mainly the fact that Andarine S4 is a stronger version than Ostarine MK2866 with more benefits, but it also carries more risks (side effects) and it’s a bit more expensive.

They are both actually similar SARMs that offer similar results and most people use both for cutting cycles.

  • Nonetheless, if you would love to save money and you are a beginner, I think that the Ostarine MK-2866 is a better option. It carries fewer side effects and it’s a great option for you to get your feet wet when it comes to the first SARMs cycles.
  • However, if you already have experience with SARMs and you do know what you can expect from running a SARMs cycle, then you could go for Andarine. I also think that you should go ahead and opt for Andarine S4 if every single pound of muscle growth and fat loss really matters to you. Andarine is likely to cause side effects, but you’re somewhat prepared, plus it will produce better results.

In the end, regardless of which SARM you’re going to opt for Andarine vs Ostarine, remember that at you can get the best SARMs on the market for competitive prices!



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