Andarine (S4 SARM) Review

What is Andarine? What effects can you expect from using this agent? Does it have any side effects? What should you know before buying it? Answers to these and other questions are provided in the following article.

What is Andarine?

Andarine, also known as S4, belongs to the SARM (Selective Androgen Receptor Modulators) group. It is one of the oldest substances of this type (first generation SARM). 

It was created by GTX Inc. to treat osteoporosis, prostate disease and muscle wasting diseases. Despite the lack of human research, it quickly gained popularity among athletes.

sarm s4 capsulesS4 is very often compared to Winstrol or Anavar. This is due to the fact that, similarly to the substances mentioned above, it allows to achieve a “pre-start physique” – dry, loaded, aesthetic muscles giving illusions of a lower percentage of body fat. 

However, unlike Winstrol, Andarine does not cause significant side effects thanks to being SARM.

SARMs connect only to androgen receptors, which are found mainly in muscles and bones. Androgen receptors play a very important role in building muscle tissue. Sex hormones connect with them giving anabolic effects. To a large extent, it is their amount and sensitivity in our body that determine our ability to build muscle.

Thanks to the selective action SARM side effects are much weaker than those of steroids or prohormones (but in the case of some substances they still occur).  


  • Shredded look – Like Winstrol or Anavar, the S4 gives you a distinctive “muscle fullness” from the very first week. It gives an optical impression of a few percent lower body fat and makes the veins more visible. 
  • Muscle mass gain – Andarine is one of the strongest SARMs in terms of anabolic strength. It gives fast and good quality weight gain in a relatively short period of time (the effect is visible after about 3 weeks of use). 
  • Greater strength – Due to its androgenic activity, it gives great strength gains. The effects are visible after 2-4 weeks of administration. 
  • Increased bone density – Primary use of Andarine. For this reason GTX Inc. has developed this product. By interacting with androgen receptors in the bones, S4 increases their density. This advantage is particularly important for older people and those exposed to an increased risk of fractures.
    When S-40503 was administered into orchiectomized (ORX) rats for 4 weeks, bone mineral density (BMD) of femurand muscle weight of levator neither were increased as markedly as DHT, but prostate weight was not elevated over the normal at any doses tested. 

Side effects

Unfortunately, despite what most people claim, SARMs are not completely free of side effects. These may not be as strong as those of Trenbolone, Winstrol or other anabolic steroids, but they are still noticeable in some cases.

Andarine has basically two side effects. 

The first is testosterone suppression. This side effect unfortunately occurs with practically every potent anabolic substance. With S4, it is not as strong as with RAD-140 or anabolic steroids, but some people may feel its consequences, especially during long cycles and when using high doses. 

Usually the suppression is so weak that it does not require PCT. The testosterone level should return to normal itself within about 2 weeks after discontinuation. For safety reasons, you can throw in some testosterone booster or maca root. 

Of course, there is nothing to stop you from using PCTs – usually using SERMs does not cause any additional side effects, and very quickly increases testosterone levels to a level above your baseline by stimulating the pituitary gland. The second, less common, possible side effect is a yellow vision. It can usually only be experienced at night. It occurs only in high doses of S4 – about 50 mg per day and disappears within a few days after discontinuation.  

It is associated with Andarine’s attachment to the receptors in the eyes. However, it does not occur in all individuals. Personally, I have experienced it. It was not something terribly annoying for me, but it is worth noting that I was prepared for the possibility of its occurrence. For a person who uses Andarine without proper knowledge about the effect of this substance and who was not informed about this possibility, it may seem terrifying. This is probably the main reason why Andarine has lost its popularity to other SARMs in recent years. 


The doses used by Andarine users vary greatly from 25mg to 75mg per day. In my opinion, using more than 50mg is not a good idea. As the dosage increases, muscle mass gains do not increase proportionally, but side effects do. 

Although the exact half-life of the substance is not known, we know that it is relatively short. For this reason, the daily dose should be divided into 2-3 servings in order to maintain a constant concentration of the agent in the blood. 

A typical Andarine cycle usually lasts 6-8 weeks and in my opinion this is the optimal length. If you want to gain more muscle tissue, it would be better to use S4 in combination with other SARMs such as Ostarin or MK-677 than to extend the cycle. 

Before and after


Andarine provides great muscle mass gains and a characteristic muscle hardness similar to that of Winstrol or Anavar. After just about a week of use, the first effects are clearly visible – reduced water retention, visible veins and harder muscles. In the second week, strength usually starts to increase, and a few days later, we start to gain weight dynamically. 

During an 8-week 50mg cycle a day, you can gain about 8lb of lean body weight. 

Where to buy Andarine?

Unfortunately, most SARMs on the market have not much in common with what the label says. Many products contain anabolic steroids or prohormones instead of SARMs. There are also a lot of products that actually have SARMs, but at a lower than declared doses. For this reason, SARMs should only be purchased from reliable sources that have a certificate of analysis for each batch of product. 

Shops we recommend:

Proven Peptides

proven peptides logo

Currently the most popular SARM store in the world. They have been present on the market for several years and have hundreds of positive opinions. They offer SARMs only in the form of solutions. Each bottle comes with a pipette and information about the amount of agent one drop corresponds to. On the website, apart from the e-mail, there is also a phone number, so you can get answers to any questions within a few minutes. They have a certificate of analysis issued by an external laboratory for each product. They also offer a loyalty program “Peptide Points” in which the collected points reduce the value of future orders. Shipping from the USA

link to their website


chemyo logo

Less popular than Proven Peptides, but offering products of similar quality. It has a great reputation especially among Reddit users. It is hard to find any negative opinions about this vendor. 

Just like Proven Peptides, they offer SARMs only in the form of solutions. Unfortunately, no pipette is included in the package. You need to buy a syringe (available on their website for $1) or a pipette on your own. Chemyo offer SARMs at very good prices compared to their competitors. They have a certificate of analysis for each product from an external laboratory, which can be downloaded directly from their website. Shipment from the USA. 

link to their website


swisschems logo

Relatively young store. Currently it is not very popular. This is probably due to the relatively high price of products. They have a certificate of analysis for each batch of products, which can be obtained by e-mail. It was included in this review since, unlike the two previous stores, it offers SARMs in the form of capsules and injections. They also offer Aromatase Inhibitors and PCTs. Shipment from the USA.  

link to their website

Frequently Asked Questions

What is the half-life of S4?

The exact half-life of this agent is not known. It has been estimated that it is about 6 hours.  For this reason, the S4 dose should be divided into 2-3 servings in order to maintain a stable blood concentration. 

Can Andarine be used by women? 

Theoretically, looking at the mechanism of action of this SARM, it should be safe for women. However, I have never seen any review of this product from women. Given its great strength, I would have opted for Ostarin or MK-677, which have been repeatedly used by women and are considered to be completely safe.  

Is Andarine legal?

At the time of writing this article, S4 is legal in the USA and in most countries of the world. It is however on the WADA list, so it cannot be used by professionals.