Andarine: S-4 Benefits, Risks, Side Effects and Dosage

Bodybuilder lifting weights with Andarine diagram overlay

What Is Andarine?

Andarine is a selective androgen receptor modulator (SARM) shown to be effective in animal studies by increasing muscle mass and bone density. However, it was withdrawn from initial clinical trials in humans because of serious safety concerns. Although illegal to use, many people don’t know about the risks – which tend to be minimized in online bodybuilding communities.

Continue reading to learn more about the drug and its side effects.

Note: This drug is not recommended for use as its safety and effects are not known. We present the most current information available from scientific and clinical literature to help readers understand the risks.

What is Andarine?

Andarine (also called S-40503, or S-4) is a SARM that was originally created for the treatment of muscle wasting disease, osteoporosis, and enlarged prostate. SARMs are selective androgen receptor modulators, which are drugs that bind to androgen receptors, which is where testosterone becomes activated.

Andarine was initially believed to be the ideal SARM because of its high oral bioavailability, and its excellent ability to build muscle and bone in animals.(1)

Although Phase I human trials of this drug were reported to have been successful, no published studies have been made available. The drug was halted from further development in order to study a different SARM with a similar chemical profile, Ostarine.(2)

Andarine’s low safety record was the probable reason, since the drug caused side effects affecting users’ vision.

How It Works

Andarine is highly attracted to the androgen receptor (AR), and in that regard it mimics the actions of testosterone. Its effects, however, are far more pronounced in the muscles and bones than in the sexual organs. For this reason, Andarine and other SARMs are thought to not have as many side effects as anabolic steroids.(3)

This belief is often used by bodybuilders as evidence that SARMs won’t cause major testosterone suppression or increased estrogens. However, these ideas have not been proven.

In fact, it’s possible that they may indeed be false. This theory has never been proven, and SARMs such as Andarine and Ostarine have not undergone adequate clinical trials. It may turn out that SARMs could prove to be more dangerous than originally thought.

Benefits of Andarine

Although Anadarine has not been studied adequately in humans, we will focus on the scientific and clinical research done thus far. However, according to the available data, it’s full effects are not known.

Increases Muscle Mass

Andarine was created to prevent muscle wasting. Animal studies have shown that this drug can increase muscle strength and growth.

Andarine increased muscle weight as effectively as DHT (dihydrotestosterone) when given to castrated rats for one month. Additionally, Andarine did not cause enlargement of the prostate, unlike DHT.(4)

Andarine was able to restore the lean muscle mass of rats 12 weeks after castration.(5)

Increases Bone Strength and Density

Andarine improved bone strength and density in castrated male rats as well as in female rats with ovaries removed (a common procedure in animal testing of osteoporosis).(6)

This drug is particularly beneficial for osteoporosis. Because it not only improves bone density, but muscle strength, Andarine could help reduce the chance of fractures due to falling.

Fat Loss

Besides enhancing bone strength, Andarine was also found to decrease body fat in female rats with ovaries removed.(7)

Potential Safety Concerns

Andarine is a drug that is not approved by the FDA and has completely unknown side effects. SARMs are thought to have less side-effects than anabolic steroids, however this has yet to be proven.

Because of a fundamental misunderstanding about the scientific data available, people mistakenly believe that SARMS such as Andarine are safer. This is a common misconception promoted in many bodybuilding blogs.

This theory, which is based on forum users talking about fewer side effects, has not been proved. Andarine and other SARMs have never been subject to adequate clinical testing. In fact, SARMs could even prove to be more hazardous than other substances (including steroids).

At the end of the day, it is not known if or by how much Andarine might suppress testosterone or estrogen production in humans.

Most common side effects reported by users are a yellowish tint to vision and difficulty adapting to night-time vision. These side effects disappear once use of the drug has stopped. Stronger side effects are seen with higher doses. Some users have reported depression.

This drug’s safety and effectiveness have not been studied in humans, or if it has, the studies are not publicly available. Andarine was primarily tested in rats.

Even though it can be purchased online, it is not known what any long-term health risks or benefits might be.

Is Andarine Legal?

The US Anti-Doping Agency has declared that SARMs are doping since 2008. These drugs are now on the World Anti-Doping Agency’s (WADA) prohibited list.(8)

Therefore, it is illegal to use Andarine in professional and competitive sports. The FDA has not approved this drug for any purpose.


This drug has not been approved by any regulatory agency or passed adequate clinical trials. Therefore, no standard dosage has been determined.

We have compiled the dosage data available from online communities while reminding about the potential dangers of using this unapproved drug.

The recommended Andarine dosage is 50mg total per day. This dosage appears to deliver the best results for most individuals with the fewest side effects.

Based upon the limited research and user reports, it is probable that S-4 has a half-life of approximately 8 hours. Therefore, in order to maintain effective levels of Andarine in your body, you should divide your doses ideally into three parts: the first in the morning, the second in the afternoon, and the third before going to bed.

The dosage can also be divided into two parts, if necessary: the first dose in the morning and the second at bedtime. Therefore, a typical dose will be between 15-25 mg, taken 2-3 times daily. Some users start with lower doses, such as 8-15 mg.

Andarine is usually cycled in periods of 8-12 weeks, depending on the user’s goals. It is often stacked with other SARMs or SARM-like compounds, including MK-677, Cardarine, or SR9009.

You should talk to a doctor before you take any drug, particularly unscheduled drugs that have limited safety data for long-term use in humans.

Where to Buy Andarine S-4

If you wish to purchase Andarine, we recommend using SwissChems. Their products are 3rd-party tested for purity and they have a proven track record for customer service and satisfaction.

They regularly have HPLC tests performed on all of their raw materials as well as finished products to ensure the quality of their brand. In fact, you can actually have the products you buy from them tested at any HPLC licensed testing facility, and if the results are negative they will refund you for the cost for the test and the total amount of your order (including the shipping).

For more information and to see the results from the latest spectrum and chromatography testing, head over to the SwissChems website.

Andarine S-4 Alternatives

For those of you who prefer a safer, legal alternative to Andarine, I would recommend the product ANDALEAN by Brutal Force.

ANDALEAN promotes muscle growth by boosting ATP production for greater strength, power and performance during resistance training. It also keeps blood sugar levels under control to minimize fat gain.

Plus, it  improves strength and energy by triggering phosphocreatine synthesis within muscle tissue. The end result being that you’ll lose fat while keeping solid muscle, giving your body a lean and cut look.

For more information about Andalean, see the Brutal Force website.

See Also: The Full Brutal Force Product Guide and Review


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