S4 (Andarine): Without Question One Of The Most Potent SARMs

S4 goes by many names such as Andarine and Acetamidoxolutamide, and it’s a type of SARM. As of the moment, there are already a lot of known SARMs, but S4 is considered to be the most potent SARM in terms of sustaining lean muscle growth and stimulating the body for fat elimination. In this article, we are going to place Andarine under a microscope and explore its finer details.


S4 may be a potent tool for building lean muscle mass and minimizing the development of fat tissues, but you’d be surprised at how it came to be. S4 was developed for the initial purpose of being a male contraceptive.

While Andarine may have shown signs of promise in this department, it was during a dissection of a lab rat that everything suddenly shifted. Researchers found out that the lab mice did not only exhibit signs of increased production of calcium (for bone density) and muscle mass, but S4 showed that it was selective in terms of tissue growth.

How it Works

S4 is a modulator as it attaches to the AR receptor and causes changes to the AR structure.

There are 3 types of chemicals that can cause a reaction on an Androgen Receptor (AR). There is the antagonist, agonist, and modulator.

picture of the molecular structure of Andarine

An agonist is the type of chemical that attaches to the AR, while the antagonist has the effect of attaching, detaching and re-attaching to the AR. A modulator is different as it attaches to the androgen receptor, but it changes the AR structure, and this is what Andarine does. Since the structure of the AR is now changed, it will also alter its function.

This means that when S4 sticks to an AR receptor and the AR receptor interacts with testosterone, the S4 chemical forces the AR receptor to send out signals that will only stimulate bone and muscle growth.

Without Andarine, when AR interacts with testosterone, it will stimulate all the effects triggered by the testosterone, which includes the good and the bad effects. Andarine is selective, and that means it will try to stimulate ONLY the good effects of testosterone.

How it is Administered

The most common and tested way of administering S4 is via the oral route (usually in the form of capsules or with a liquid dropper). The dosage may vary depending on a couple of factors, which we will cover later in the article.

Advantages of Using This SARM

  • The great thing about S4 is that while it stimulates bone and muscle growth, it does not stimulate the growth of secondary sex organs such as the prostate.
  • S4 does not interfere with the HDL/LDL ratio, also known as good cholesterol / bad cholesterol ratio. This means that S4 does not pose any threat to the cardiovascular system.
  • S4 is very selective in stimulating the type of muscles and bones for growth. It does not cause the heart to enlarge or cause damage to the neighbouring organs.
  • What’s more, S4 does not inhibit the levels of testosterone, which means that there’s no need to worry about extensive PCT and virilization.

Disadvantages of Using

  • S4 is not a perfect SARM, which means it comes with a few side effects. One of the most commonly known disadvantages of S4 is the fact that its effect is heavily subjected to the law of diminishing returns. This means that there’s a certain limit and as you increase the dosage, you will be getting less returns.
  • Some users have reported that S4 has caused a yellow tint to their vision. Keep in mind that this is not a permanent side effect. Once you stop taking S4, this side effect gradually diminishes as the S4 leaves the body.

Potential Side Effects

Your vision can be effected when using this SARM. Some users have reported a yellow tint to their vision and also poorer clarity in the dark.

These side effects should reverse once you stop using S4.

Dosage to Be Taken

  • For Cutting – The best dosage should be around 50 mg for 6 – 8 weeks. Take a two-day break after this to avoid the side effect it causes to the vision.
  • For Recomping – The best dosage for recomping should be around 50 – 70 mg for 4 – 8 weeks.
  • For Bulking – The best dosage should be around 50 mg and above for 6 – 8 weeks.

Is PCT Needed?

Because S4 does not inhibit the levels of testosterone, rather it simply causes the AR receptors to react differently, you don’t need to do heavy PCT. Having said that, it’s advisable that you do a light PCT with HCgenerate, Nolva or Clomid.

Can Women Use It?

S4 capsules are not known to produce any androgenic effect. Hence, there’s little to zero chance that it may cause virilization in women. In other words, women can take Andarine without having to worry about developing a deeper voice, clitoris enlargement, and excess body hair.

What Other SARMs Stack Well

Andarine is effective enough to be used as a standalone. However, it’s still possible to stack it with other SARMs to increase its effectiveness. It’s also able to stack with anabolic steroids to increase results while diminishing the side effects.

It’s in the process of cutting in which most people would stack S4 with GW-501516 and Ostarine.

What is the Half-Life?

When compared to other SARMs, S4 is known to have a short-acting cycle. Specifically, S4’s half-life is between 4 to 6 hours. Because of this, it’s common for users to split the dosage so its effect can be continuous all throughout the day.

How Long Until You See Results

S4 is a relatively fast-acting SARM. In fact, you should be able to notice the first results in just 7 days. Of course, the exact time frame is hard to determine as each body has its own physiology. Furthermore, there are also other factors that may impact the results, like diet and physical activity program.

Will This Make an Athlete Fail a Drug Test?

Most drug tests are not designed or sensitive enough to detect it yet. It also depends on who is doing the testing. For example, if it’s WADA that’s doing the drug testing, then the chance of being detected is higher. Even then, there are cases that even a WADA drug test results can’t detect Andarine and other SARMs.

How to Buy

Well, the chances of buying S4 from your local bodybuilding store is little to none. Your best bet would be to buy it online. Just be extra cautious as the online SARM shops are known to send fake stuff.

What are the Current Laws?

FDA has no legislation that would prohibit the sale, purchase, and distribution of Andarine. But since it’s closely related to anabolic steroids (which is illegal), this may change in the near future.

In the UK and all throughout Europe, Andarine does not have problems with the law.

Follow us on Social Media.