In this article, as part of our Ultimate Series on SARMs, we will consider S4 (Andarine), including its uses and effects. Like Ostarine, Ligandrol and RAD 140, Andarine is a powerful anabolic substance that was first developed to combat muscle wastage, osteoporosis and enlargement of the prostate, and is now being put to muscle-building purposes by a variety of different groups, including bodybuilders, weightlifters and athletes. 

What is S4?

Andarine, which is also known as S4 or GTx-007, is a selective androgen receptor modulator (SARM) that was developed by GTX Inc – also the developer of Ostarine – to treat a variety of conditions including muscle wasting, osteoporosis and prostatic hypertrophy (enlargement of the prostate).

S4 Andarine Molecule
S4 Andarine Molecule (C19H18F3N3O6)

In the previous articles on Ostarine, Ligandrol and RAD 140, we have touted the anabolic potential of these new compounds for athletic performance and aesthetics, but we have also been at pains to ensure you understand that they have specific uses that will some suit individuals and contexts more than others. That caveat applies here too.

If you put S4 Andarine to the right uses, you will see positive results, with fewer of the side effects associated with the use of performance-enhancing substances like steroids. 

You must, however, be in no doubt of the potential risks and side effects, which we will discuss below.


The S4 Lowdown

As an another anabolic SARM, like Ostarine, Ligandrol and RAD 140, Andarine is generally used by bodybuilders, strength athletes (powerlifters, Olympic lifters, strongmen), practitioners of contact sports, martial artists and gymbros. The benefits of Andarine are:

  • Increased lean muscle mass (including during a calorie deficit) and therefore strength
  • Increased energy levels
  • Increased bone strength 
  • Decreased body fat

Andarine, as a SARM with performance-enhancing effects, is listed as an S1 Anabolic Agent on WADA’s prohibited list. In our articles on Ostarine and Ligandrol, we have used lists of athletes who have been banned for using those substances, in order to illustrate their respective properties.

In the case of S4 (Andarine), like RAD 140, it is much harder to find evidence of athletes who have been banned or received sanction for using the substance.

S4 (Andarine) and RAD 140 both seem to be less well known than Ostarine and Ligandrol; although that is not necessarily reason to assume that Ostarine and Ligandrol are the best or better SARMs than Andarine and RAD 140.

Among the cases we could readily find were those of Kayle Leogrande, a cyclist banned for testing positive for Andarine among other substances, and the Australian horse trainer Stuart Gower, who received a sanction when the horse Saturday Sorcerer tested positive for S4 (Andarine) after its win in the Darwin Cup.

There have been no clinical human trials on S4 Andarine. It is regarded as being weaker than other SARMs like Ostarine and Ligandrol and is usually stacked with other SARMs to increase its effects. We will discuss how to stack SARMs in a separate article. 

In addition to its anabolic properties, S4 (Andarine) is touted as one the best SARMs for fat loss, based on clinical trials in rats, which showed a significant decrease in body fat [R].

S4 (Andarine) has a unique side effects among SARMs in that many users report altered vision. We will discuss this side effect later.

Legendary YouTuber MorePlatesMoreDates takes on S4

How S4 Andarine Works

S4 Andarine from Rats Army
S4 Andarine from Rats Army

SARMs induce anabolic activity – growth – by directly stimulating the body’s androgen receptors. These are specific sites within the body to which androgenic (i.e. male) hormones, including testosterone and androsterone, bind. 

The activity of these androgen receptors, and the binding of androgens to them, is crucial to the proper expression of male characteristics, including muscle growth and reproductive function.

In the womb, androgens are responsible for sexual differentiation, and then during puberty they regulate the development and function of the penis, prostate and other sexual organs, as well as inducing growth spurts, larynx development and growth of skeletal muscle.

For adults, androgens regulate behaviour, the production of sperm, muscle growth, bone function and aspects of the cardiovascular system. Androgens regulate sexual function and are responsible, in part, for aggressive behaviour in men. As a result, disregulation or blocking of the androgen receptors can lead to all sorts of conditions. 

S4 (Andarine) binds to the androgen receptors and mimics the effects of testosterone, increasing protein synthesis and therefore muscle growth.

This is also what steroids do, but SARMs generally have an advantage over steroids, because they only bind to receptors in skeletal muscle tissue. Steroids, by contrast, work on other tissues in the body and have, as a result, been linked to all sorts of side effects, including prostate and heart problems.

SARMs are also non-aromatising, meaning that they aren’t converted to estrogen by the body in an attempt to maintain the body’s testosterone-to-estrogen balance.

By contrast, aromatisation can occur when using steroids or testosterone injections, which upset that balance, leading to problems such as gynecomastia (formation of breast tissue).

Although there is no certified research on the use of this SARM for bodybuilding purposes, research in other contexts indicates that Andarine has the potential to enhance lean muscle mass growth [R]. 

To date, however, there have been no human clinical trials involving Andarine.

Generally, because it is considered to be weaker than Ostarine or Ligandrol users stack Andarine with other SARMs, such as RAD 140, for bulking, increasing strength, cutting and body recomposition. We will discuss SARMs stacks in detail in a separate article.

One Reddit user writes of his S4 (Andarine) cycle:

‘In these 6 weeks I lost 8 pounds of fat and was able to hold on to my muscle much better then [sic] I would have without S4. Vascularity was insane around week 3-4. S4 did exactly what I expected from months of researching and reading logs on here.’

Here the main benefits were clearly fat loss, muscle retention and increased vascularity.

Another user said that he preferred Andarine to Ostarine, although Ligandrol is his favourite SARM.

‘I’ve done both osta and lgd as well as s4. In my opinion S4 is slightly better than ostarine and the reason for that is I felt more strength increase from it which also included more vascularity. However, LGD was my first cycle ever and I prefer that over any other sarm. I like it enough that I am going to run a mini bulk cycle at 6mg per day for 6 weeks and then a mini cut at 3mg per day. Yes, I am going to try LGD lower mg for a cut cycle. I’m interested to see how it compares at 3 mg vs 50mg s4 and 20mg osta.’

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Ryan Russo, of the Russolifts Youtube channel, states that he dislikes Andarine because of the altered vision side effect. While others are able to tolerate the altered vision, he was unable to do so.

How to Use S4 (Andarine)

S4 (Andarine), like the other SARMs, is administered orally. There is no need to inject it, as you would steroids or other compounds like human growth hormone. 

The best way to use Andarine is in a cycle of six to eight weeks, in a stack with other SARMs. This will give you significant gains and then allow your body, including your body’s testosterone levels, to recover. It’s a bad idea to lengthen a cycle beyond 12 weeks, because of the hormonal side effects and because the long-term effects of taking SARMs are at this stage unknown. 

Remember: the more you take, the greater the effects. The general dosage favoured seems to be 10 to 15mg a day.

However, it should be noted that the more you take, the greater the side effects will be. As is well known, this is also the case with steroids; although even at higher doses, SARMs will not have the same side effects as steroids.

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How S4 Compares With Other SARMs


According to one user report:

Here are two testimonies, taken from Reddit, from users of Ligandrol.

‘I finally gained 3 pounds after only 2 weeks! Solid mass! All of my max weights have been upped by at least 20 to 30 pounds. I’m hitting weight I’ve never even touched before. My wife straight asked me if I was on roids and I said no but close, sarms.’

Another user wrote:

‘I am now a week into a cycle and have the gains of a month straight of me working my ass off… I’ve got my 6 pack back in a week and all the fat on my stomach that was my original problem is now almost non existent. I will post before after pictures so I may prove the effectiveness of this SARM but damn I’m… elated right now. I’ve recommended it to my skinny brothers as well as I know they will gain and bulk up with just 4 weeks of this supplement. Guys, I’ve taken oral gear before and had gyno [gynecomastia – growth of breast tissue] issues almost immediately. So far no side effects’ 

A user from the Anabolic Minds forum, who was almost certainly taking a higher dose than the usual dose most users of Ligandrol take, reported the following increases over a period of just a single month.

  • 12lbs increase in body weight
  • 60lbs increase in squat
  • 45lbs increase in bench press
  • 60lbs increase in deadlift
  • 35lbs increase in standing press


Users report gains of around 5-7lbs of lean mass over a period of six weeks , as well as increased strength and endurance. One experienced powerlifter on Reddit describes his experience with ostarine thus.

“The first week, I immediately noticed the effects of the drug. At first I thought it was a placebo effect. However, the effect continued- I was not getting sore after my training sessions and I was able to perform significantly more volume work during the training sessions.

“As an experienced lifter, I am not often “de-trained,” so I am seldom “sore” after lifting.

“However, the type of pain I usually feel is fatigue and deep soreness of your body being wrecked from very heavy weight. Sets of 5 at 85% of your 1RM will wreck you.

“With Ostarine, they didn’t wreck me. I really didn’t feel wrecked. I felt like I lifted the next day, sure, but I didn’t have the “hit by a truck” feeling. It was crazy. I couldn’t believe it.”

Although he only took Ostarine for a short period, he noticed serious changes within a week.

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S4 Andarine Side Effects

As we’ve already noted, the side effects of SARMs in general are much milder compared to those of traditional androgenic agents including steroids.

With Andarine, an unusual and much reported side effect involves altered vision. The Reddit user quoted above said the following. 

“First it was barely noticeable and just a yellow tint on white walls. Then it progresssed [sic] to be a mild light sensitivity when going from outside back to indoors. Everything was much darker then it appeared until my eyes got adjusted. At night time it started to feel as if my peripheral vision was slightly restricted (as if I was wearing binoculars.) I went up on my dosage to 60mg towards the last 2 weeks and the vision sides only got slightly worse. The night time peripheral blindness was alarming at first but I got used to it quickly. My driving was not completely impaired because of this.”

Other users chimed in with their own experiences of these side effects. 

MorePlatesMoreDates talks about certain side effects of S4

Without clinical studies in humans, there is no scientific evidence for Andarine’s side effects. It’s worth saying that Ostarine, Ligandrol and RAD 140 have been flagged for potential liver damage, as indicated by elevated liver enzyme levels. Users of these SARMs report mood swings, acne, small amounts of hair loss and reduced libido. Some report experiencing more or less no side effects whatsoever, though.


Some of the reported symptoms of SARMs are clearly associated with reduced natural testosterone levels. As with steroids, the use of SARMs including Andarine will reduce natural testosterone levels. The reduction will correspond with the amount you take and for how long. You may notice some visible shrinkage of the testicles.

As a result, after a SARM cycle, it may be wise to engage in a round of post-cycle therapy, as many steroid users do. Note, though, that because the side effects, at least in the short term, appear to be much less serious than for steroids, the post-cycle therapy will almost certainly need to be less severe.

Post-cycle therapy helps to restore your natural testosterone levels, and may last up to six weeks. Various supplements and medications are available, which we will discuss in a separate article on SARMs stacks. You can begin post-cycle therapy as soon as you stop taking SARMs.

The longer term effects of SARM use are, at this stage, unknown and it’s worth reiterating that SARMs aren’t legally certified as a dietary supplement. You are taking a risk if you use them; but you are also taking risks lifting heavy weights, running – or even just stepping outside your front door. Ultimately, it is a decision for you to make, based on willingness to balance the risk against the potential rewards.

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Is Andarine present in other supplements?

Jon Anthony SARMs results
Jon Anthony SARMs results in 2 months

Generally, no. In large part, this is because SARMs are not approved for human consumption in the US or any other country. As a result, there are no legal medications or dietary supplements that contain SARMs, and that includes Andarine. 

However, in certain cases it appears that some supplement manufacturers have put SARMs – illegally – into their supplements and labelled them as ‘legal steroids’ or chemicals for ‘research purposes only’.

In the US, for example, companies have been warned for attempting to sell Ligandrol as a dietary supplement. In 2017, Infantry Labs and Panther Sports Nutrition were both told by the FDA to cease distributing a dietary supplements that contained Ligandrol.

If you have any doubts about a supplement, first consult the label and then, if you are not convinced, check the USADA’s Supplement 411.

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Disclaimer: we are not medical professionals. If you wish to consume SARMs and/or other performance enhancing drugs, we urge that you take the appropriate channels and consult your physician. Please ensure that you request comprehensive bloodwork to protect your health, under the care of your physician.

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