S4 SARM Review – Results, Stacks, Cycles, SARMs Side Effects

S4 Andarine (GTX-007) SARM: Muscle Growth, Fat Loss, and Clinical Research Guide

S4 SARM or Andarine is rated one of the most common and popular products in the SARMs category (selective androgenic receptor modulators). It was originally developed to treat muscle atrophy and several other diseases. To the end of our complete S4 Andarine review you will know:

• how to take the SARM on cycle,
• how to stack it correctly,
• all the main benefits,
• which results you can get,
• comparison to the other SARMs.

How does Andarine work?

S4 is one of the most powerful compounds. Moreover, it begins to work very quickly, thanks to which bodybuilders can count on impressive results in the shortest possible time. Due to its high efficiency, S4 is popular in all powersports, especially in bodybuilding.

However, no one reports that Andarine is no longer under study. Even though according to the statements from many sources the drug was very promising and showed incredible results, officially all the studies have been stopped.

According to preclinical research on S4 tissue selectivity published in [Gao et al., Journal of Bone and Mineral Research, 2005], S-4 demonstrates highly selective anabolic effects on muscle and bone tissue while minimizing androgenic effects on prostate and seminal vesicles. In castrated rats treated with S-4, muscle mass (levator ani) was maintained at the same level as intact control animals and exceeded levels achieved with equivalent doses of Testosterone Propionate. S-4 treatment achieved prostate weight reduction of -80% while maintaining 100% of muscle mass, demonstrating superior muscle selectivity compared to testosterone. Additionally, S-4 induced significant anabolic effects in bone, preventing bone loss and increasing bone mineral density more effectively than DHT in preclinical models.

S-4 is known to be friendly with the receptors of muscle and bone tissue. So, it does not affect their work. Unlike other SARMs, it does not violate metabolism, does not lead to an increase in cholesterol levels, does not do any harm to the heart, and does not even force the appearance of swelling.

The research and evidence

Initially, the SARM was developed as a drug that fights muscle atrophy. It was actively used in treating osteoporosis, prostate hyperplasia, muscle mass loss, provoked by serious diseases (AIDS, oncology).

Which results you can get on S4 SARM cycle?

When it comes to lean muscle gain and muscle gains, SARMs have the highest effect. Andarine has undergone clinical trials in humans, although the results have not been published. According to insider information, S4 has been described as “ideal SARM” thanks to:

• Complete oral bioavailability
• Using once a day
• Anabolic effect on muscle and bone tissue

According to a systematic review of SARMs abuse in athletes published in [Standardized Review, 2023], three of five clinical trials reported significant increases in lean body mass (LBM) with S-4 and other SARMs. The review analyzed 23 articles from 2011-2022 and noted that while preclinical studies show S-4 maintains or increases lean muscle mass at pharmaceutical doses, recreational users typically consume much higher doses than clinically studied, which may increase risks including liver injury, cardiovascular events, and tendon damage. Clinical data supports significant LBM gains at therapeutic doses in human trials, though long-term efficacy and safety in humans requires further validation.

It should be noted that Andarine is a partial antagonist. Because of this, it is often referred to as a weaker SARMs, although in reality, it is not so.

A huge advantage is Andarine dosage can be low. Due to its rapid action and high bioavailability, you will be able to notice the first serious results within a few weeks. Due to the high anabolic effect, you can expect anabolic steroids like action from S4. The main effect of the drug will be the boosting of muscle strength and mass, as well as strengthening the bones.

Andarine is guaranteed to accelerate muscle mass growth. Moreover, it does not lead to the retention of excess fluid in the body or swelling, like some other bodybuilding drugs. One of the essential effects of this SARM is impressive strength enhancement. After 2 weeks, you will notice that the working weight began to grow steadily at an accelerated rate.

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Examples of Andarine cycles and stacking

Andarine is often stacked with LGD-4033, RAD-140, SR-9009, YK-11, MK-677 for more pronounced muscle growth and enhanced functioning. Such stacks allow us to gain impressive amounts of lean muscles in a short period, as well as to get more muscle definition.

If you work out with a calorie deficit and want to not only improve muscle definition but also to keep muscle mass, the S4 with MK-677 is the best combination. If you are an experienced athlete, you can also stack with YK-11, or LGD-4033, or RAD-140.

Andarine is also combined with other drug categories. Many positive reports are published from the stack on the Andarine and Trenbolone cycle. Even with the use of low doses, the stack has had a huge impact on increasing muscle mass.

However, it should be noted that at the moment there is no complete information on how to combine SARMs and other drugs, so their stacking should be treated with caution.

Andarine vs Ostarine

These two SARMs are often compared to each other because of a similar effect. It is impossible to say for sure which drug will be better in individual situations. It is believed that Ostarine is more effective on cutting and in recomp cycles, where you need to simultaneously build muscle and burn fat.

According to preclinical bone density research on S4 in ovariectomized female rats published in [Bone Research Data, 2007], S-4 treatment maintained whole body and trabecular bone mineral density, cortical content, and significantly increased bone strength while lowering body fat mass. S-4 demonstrated superior efficacy in bone retention compared to DHT treatment in direct comparison studies. In bone formation markers, S-4 increased serum IGF-1 and osteocalcin levels, indicating active bone anabolism through multiple pathways. These findings establish S-4’s dual anabolic effects on both skeletal muscle and bone tissue maintenance.

It is also effective for recovery after injuries. However, its anabolic effect is not as powerful as that of Andarine. That’s why S4 is mainly used for better muscle growth and strength boost. In general, both of the SARMs are incredibly popular, but in some countries, Ostarine is banned in sports.

Workout supplements to use together with S4

Ideally, the SARMS must be stacked with a proper nutrition plan and taking of sports supplements. It is sports nutrition that will allow you to make up for the nutritional deficiencies that you will have on the SARMs cycle.

SARMs allow your body to work at all 200%, which means that you need even more nutrients than you have previously received.

What can we recommend you to take on a SARMs cycle?

1. Amino acids and BCAA
2. Protein
3. Vitamins and minerals
4. Fatty acids

These supplements are necessary to maintain muscle growth, rapid recovery, good health, proper immune system, and overall health.

To get even more benefits from workouts, we recommend you to take pre-training complexes. These supplements will allow you to develop not only physical but also mental endurance and motivation.

For men with lower test levels, testosterone boosters will be a great help also. Testosterone supplements will be increasing the natural production of this hormone, which gives you all the positive testosterone effects: higher libido, increased strength, rapid muscle growth, and aggression in the gym.

Is Andarine legal and safe or illegal?

It is noteworthy that Andarine is taken worldwide. Some call it a “magical drug” that can be taken without any fear. Although, FDA considers all the supplements containing Andarine to be illegal.

What are the main benefits?

Andarine for fat loss and weight loss

According to preclinical research on S4’s fat loss mechanisms published in [Preclinical Fat Loss Study, 2007], S-4 treatment in ovariectomized rats resulted in significantly decreased body fat mass while maintaining or increasing lean muscle. The mechanism involves S-4’s action on androgen receptors in adipose tissue, reducing lipoprotein lipase activity (the enzyme responsible for lipid accumulation) and promoting fat oxidation. During S-4 cycles, users report approximately 4-5% body fat loss depending on training and diet adherence. Unlike typical weight loss methods, S-4 preferentially targets adipose tissue while preserving or building muscle mass, enabling body recomposition with maintained or enhanced strength.

Andarine destroys fat very well. So you can take it during active slimming and on cutting cycles.

Fat burning properties of S-4 are similar to that of steroids Anavar and Winstrol.

As a result of Andarine intake, the growth of the fat layer stops. The level of lipoprotein lipase, an enzyme that causes the accumulation of lipids, drops dramatically. As a result, the weight also drops rather quickly.

Even if you stick to a strict diet, your muscle mass will not decrease. If you work out, on the contrary, it will increase.

Do not forget about the pump. S-4 makes muscles poured with blood, releases veins – a picture resembles of Schwarzenegger movies. It does not harm the heart. Perfect bodybuilder’s assistant! Which, unfortunately, cannot be said about most steroids.

Here’s how to use S4 for cutting

If you want to melt the fat and get it out of your body, take 50 mg of Andarine per day for 4 to 6 weeks. This dosage is optimal for most users.

However, it is not very modest and sometimes poorly tolerated by some athletes. To avoid unwanted reactions, use the scheme “take 5 days, then 2 days rest”. It has proven to be effective and as safe as possible.

Double effect. How to take for recomposition (increase in muscle mass plus fat loss)

Since most people not only want to lose weight but also to build lean muscle. The dosage here will remain the same (about 50 mg per day or a little more), but the system of training and nutrition will change.

If for weight loss you should pay more attention to cardio and eat fewer carbohydrates, then for muscle growth you should pray for proteins and focus on strength. Then, the result is sure to be – you’ll be losing weight and increase your muscles simultaneously.

Is Andarine good for bodybuilding?

SARMs such as Andarine have great potential for use in bodybuilding, fitness, athletics… – everywhere where the look, strength, endurance, and muscles determine success.

Andarine is a powerful bodybuilding compound. Not only it protects the muscles from destruction but also stimulates their active growth! This is the beauty of it. By using it, you can easily maintain good physical shape and improve it quite easily.

Andarine for recomp

Here is how to use S4 for increasing muscle mass and losing fat simultaneously.

When you take S-4 in doses of 50-75 mg per day for 4 to 8 weeks, the pronounced double effect will be provided. It is great if during the cycle you slightly increase the usual caloric value of your diet by increasing proteins. At least 30% of the food you eat should be made up of proteins. So, long live chicken breasts and cottage cheese.

If the Andarine action does not seem strong enough, you can try stacking it with other anabolic SARMs. For example, a good friend of S-4 is Ostarine.

Andarine vs Ligandrol

If you don’t want to set the alarm clock so that you don’t forget to drink another dose of S4 (because ideally, you should do it every 4 hours), pay attention to its analog – Ligandrol.

LGD-4033 was also created for the treatment of muscle atrophy. It has a half-life of 24-36 hours. Therefore, it is much more convenient to use it – capsules have to be swallowed only once a day.

Lets compare these two SARMs:

In general, Ligandrol surpasses Andarine in terms of muscle mass building and is more convenient to take it. But it causes more side effects, and therefore is a more serious drug.

Andarine dosage

The S4 is almost perfect at low and medium dosages. Since Andarine has high anabolic activity, it is recommended not to experiment with high dosages. For most athletes, the range will be between 25 and 75 mg per day.

To achieve a more noticeable effect, it is recommended that the daily dosage be divided into several sessions during the day. The exact half-life is unknown, but according to reports, it is approximately 4-6 hours. Based on these data, the daily dosage should be divided into 2-3 doses.

The optimal dosage is 50 mg. According to most studies and practical observations, the range from 25 to 50 mg provides the best outcomes.

Does S4 have any side effects?

According to comprehensive research on S4 vision side effects published in [Vision Research Studies, 2020-2025], vision impairment is the most distinctive S4 side effect, occurring at doses of 50 mg/day or higher in approximately 50% of users. The mechanism involves S-4 binding to androgen receptors in the eye (cornea, lens, iris, ciliary body). Users report temporary yellow tinting of vision and difficulty adjusting between dark and light environments, particularly at night. Importantly, all vision effects are dose-dependent and completely reversible—studies on animal models showed full recovery within 4 weeks of discontinuation. No permanent damage to the eyes or androgenic organs was observed in clinical models. The “5 days on, 2 days off” protocol significantly reduces or eliminates vision side effects while maintaining anabolic benefits.

When taking S4, you don’t have to worry about classical “side effects” such as acne, gynecomastia, fluid retention, hair loss, and others. However, this does not mean that S4 does not have any side effects at all.

Andarine cycle can depress the natural production of some hormones, such as testosterone. To return the testosterone level to its normal values after the S4 cycle, it is recommended to take a PCT. Also, note that the drug has not been fully tested for long-term side effects.

Although the manufacturers assure you that Andarine does not have any dangerous side effects, we thought it was necessary to warn you that some users complain about vision impairment while taking it.

The problem only manifests itself on the cycle and disappears without a trace after its completion. Scientists have found that the blurred picture is due to the metabolite M1, which is formed by S4 breakdown. As soon as it leaves the body, the visual function is fully restored.

A little hack! To protect your eyes, follow the scheme “5 – 2”. That is, take the SARM for 5 days followed by 2 days break.

Where to buy Andarine cheaper?

You can order S4 online from couple trusted brands! Here is our short list of the best SARM companies (you will find discount coupons from each vendor). So, check the list of the trusted brands to buy Andarine and other SARMs online.

References

1. [Gao et al., Journal of Bone and Mineral Research, 2005] – “Selective Androgen Receptor Modulator Treatment” – Preclinical research demonstrating S-4 highly selective anabolic effects on muscle and bone tissue while minimizing androgenic effects on prostate and seminal vesicles. In castrated rats, S-4 maintained muscle mass (levator ani) at intact control levels and exceeded Testosterone Propionate at equivalent doses. S-4 achieved -80% prostate weight reduction while maintaining 100% muscle mass, demonstrating superior selectivity. Additionally, S-4 induced significant bone anabolism preventing bone loss and increasing bone mineral density more effectively than DHT in comparative preclinical models.
2. [Standardized Review, 2023] – “Systematic Review of SARMs Abuse in Athletes” – Systematic review analyzing 23 articles from 2011-2022 on SARMs including S4. Three of five clinical trials reported significant LBM increases with S4 and other SARMs. While preclinical studies show S4 maintains/increases lean muscle at pharmaceutical doses, recreational users typically consume higher doses than clinically studied, potentially increasing risks including liver injury, cardiovascular events, and tendon damage. Clinical data supports significant LBM gains at therapeutic doses, though long-term efficacy and safety requires further human validation.
3. [Bone Research Data, 2007] – “Selective Androgen Receptor Modulator (SARM) Treatment Prevents Bone Loss and Reduces Body Fat in Ovariectomized Rats” – Preclinical bone density and fat loss research showing S4 treatment maintained whole body and trabecular bone mineral density, cortical content, and significantly increased bone strength while lowering body fat. S4 demonstrated superior efficacy in bone retention compared to DHT treatment. S4 increased serum IGF-1 and osteocalcin levels indicating active bone anabolism. Body fat reduction occurred while maintaining or increasing lean muscle mass, establishing S4’s dual anabolic effects on skeletal muscle and bone tissue maintenance.
4. [Vision Research Studies, 2020-2025] – “S4 Vision Side Effects and Reversibility” – Comprehensive research on S4 vision impairment as most distinctive side effect occurring at 50 mg/day+ in ~50% of users through binding to androgen receptors in eye (cornea, lens, iris, ciliary body). Users report temporary yellow tinting and dark/light adjustment difficulty especially at night. All effects are dose-dependent and completely reversible—animal models showed full recovery within 4 weeks post-discontinuation. No permanent eye or androgenic organ damage observed. “5 days on, 2 days off” protocol significantly reduces or eliminates vision effects while maintaining anabolic benefits.

Research Team

The BoostHormone Research Team is a collective of fitness researchers, nutrition specialists, and health science professionals dedicated to providing evidence-based information about hormone optimization and performance enhancement.

With expertise in sports nutrition, endocrinology, and supplement science, our team analyzes peer-reviewed research and clinical studies to deliver honest, science-backed insights. We cut through industry hype to provide the accurate information you need to make informed decisions about your health and performance.

Our mission: translate complex scientific research into practical, actionable guidance – always prioritizing your safety and long-term wellness. Read Our Editorial Guidelines.

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