S-40503: A SARM for Bone Healing

In the bodybuilding world, using supplements help you achieve your body goals. And while traditional anabolic steroids will get you results, they can take a toll on our health. However, cycling through SARMs can provide the same beneficial results without the adverse side effects associated with testosterone use.

S-40503, one of the latest SARMs to hit the market, is also one of the safest to use. In fact, S-40503 may even be OK to use for women who wish to body build or improve their overall muscle mass. Interested in seeing how a cycle of S40503 can help you achieve your body goals? Keep on reading to find out how to safely and efficiently take this new SARM.

What is S-40503 and what was it designed for?

What is S-40503?

S-40503 is a SARM (Selective Androgen Receptor Modulator) that is still currently under testing. Developed by the Japanese company Kaken Pharmaceuticals, it was mainly designed to treat bone deficiency disease. S-40503’s primary function is to help treat osteoporosis. Those who take S40503 display good bone tissue growth and show a slight increase in muscle mass. Better yet, this SARM appears not to affect the prostate or testicles either.


How does S-40503 work in the body?

Effect on Bones

Like I said before, this SARM is primarily for bone growth. But, some skeletal muscle mass has been observed as a welcomed side effect. In animal studies, S-40503 improve bone mineral density for those treated animals. Its benefits for the body also appear to be dose specific. In small doses, S40503 only affects bone tissue. But when the amount is increased, both bone and muscle growth were observed. However, no matter high or low the dose, the prostate wasn’t affected at all.

Is S-40503 safe for humans to use?


Because of how S40503 interacts with the body, this SARM is one of the mildest and safest to use. However, there are a few things you’ll want to know before starting a cycle of S-40503:

  • S-40503 will be detectable in the blood and urine for 72 hours.
  • Read through WADA rules and ask a professional coach before taking any SARM, just to make sure you’re not breaking existing competition rules.

What are the Benefits of S40503?


SARMs, especially S40503, can have wide-ranging benefits on the body. Below are a few of the most revered benefits S-40503 has when taken correctly:

s-40503 study

Taking S40503 Can Help Build Muscles and Increase Stamina

SARMs specifically target skeletal muscle mass. This skeletal muscle mass is the most important for achieving when trying to achieve a muscular appearance. By taking S-40503, you can expect noticeable muscle gains, all without the side effects that come with anabolic steroids. Also, S40503 will increase your stamina similar to Cardarine, as a result of building skeletal muscles.

S-40503 Helps to Maintain Bone Density and Possibly Help Keep Muscle Growth

Because of how S 40503 was designed, it’s great for improving overall bone health. While more studies are needed to see how it affects muscle growth, odds are it will help maintain skeletal muscles as well.

It’s One of the Safest SARMs to Take on the Market

Unlike anabolic steroids, S40503 has no risk of affecting your overall well being. When cycling S 40503, you can expect your moods to be unchanged. Also, you won’t have to worry about any cardiovascular or testicular problems, as well.

S 40503 can Increase Bone Density and Improve Mineralization

Like other SARMS, using S 40503 can help improve bone density and mineralization. However, if you suffer from a bone disease, always consult with a doctor before going forward with an S-40503 cycle. Cycling with S 40503 could affect any bone-density medications you may already be using.

S40503 Might be OK for Women to Use

Unlike other SARMs, S 40503 has no virilizing effects on the body. Because of this, it may be safe for women to use. Women, too, are often more prone to osteoporosis than men.

While the universal gender outlook for S-40503 is promising, additional data about S-40503 is needed. Let us hope this SARM will be further developed and more widely available in the future.

Potential side effects of using S 40503 for bone healing

Side Effects

Because S-40503 doesn’t affect testosterone, it produces minimal side effects in the body. It’s also a not a metabolic viralizer. All in all, S-40503 might be one of the safest SARMs on the market.

Where can I find S40503 for sale?

Where to Buy

S-4503 is hard to come by online. Because it’s so new on the market, few online stores and vendors are selling S4503. But no matter how your S4503 will be buying, it will come with the SARM label “for research use only.” Like other SARMs, S-4503 isn’t accepted by the to be FDA for human consumption.

However, you can find S-40503 available through one of these sources. Their S40503 product is manufactured from the very same Japanese labs the drug was first created. When buying from one of these reputable sellers, you can rest easy knowing your S-40503 is of the highest quality.

How much S-40503 to take for healing bones?


S-40503 is chemically very similar to Andarine, although much weaker. Dosings of Andarine are recommended between 50 to 75mg a day. It can even be tolerated as high as 100mg. But like many SARMs, start low and gradually increase the dosage. This gentile increase will allow your body to adapt to the substance best. By starting slow, you’ll also be able to see if you have any side effects to S-40503.

S-40503 has a known half-life of four hours. Because of that short half-life, I’d recommend splitting your dose so that you can take it at least twice a day. If possible, dosing three times per day is ideal.

Cycle up to at least eight weeks, which is longer than most other SARMs. S 40503 is not hepatotoxic, so long or repeated cycles won’t cause damage to the liver.

Common questions about S-40503 and other SARMs


Like when researching any new supplement to take, many questions can come up. Here are a few of the most frequently asked about S-40503:

When will I notice results from taking S-40503?

Because S-40503 is much milder than other SARMs, results can take time. I wouldn’t expect you to see any visible results in less than a month’s time. But if you cycle for a full eight weeks, you’ll see changes by the end.

Can S-40503 be injected?

S-4050s is only available on the market in orally ingestible forms. As of now, no S4503 creams or injectables are for sale.

What’s the best way to take S 40503?

Orally via capsules or tinctures is the optimal way to take S-4503. This SARM has high bioavailability, so it will remain intact when ingested in capsule or pill form.

Will I need a TRT or PCT after doing a cycle of S40503?

No, you won’t! S-40503 will not affect your HPTA (Hypothalamic-Pituitary-Testicular Axis) system at all. And unlike anabolic steroids, S-40503 won’t offset your testosterone levels. Because you’ll be maintaining regular testosterone levels while using S4050s, you won’t have to follow with a TRT (Testosterone Replacement Therapy), either.

Can S-40503 cause prostate or testicular damage?

Nope! S-40503 is one of the mildest SARMs on the market, and it’s also not a virailizer. This means that it can’t throw your sex hormones out of balance. These stable hormonal levels will keep your prostate or testicles healthy.

Final thoughts on S 40503


SARM offer a fantastic alternative to anabolic steroids. Because they increase mass safely, SARMs like S 40503 are gaining popularity. They’re great for bodybuilders and people who want to improve their physique. Better yet, S 40502 is one of the safest SARMs to use on the market. But just like other SARMs, it’s best to dose S 40503 on the small side before increasing.

Make sure you order your SARMs from a reputable source. You can find a list of SARMs sources here.

Chris Jackson
Chris Jackson

Chris Jackson, co-founder of Sarms.io, is a renowned fitness blogger, physique model, and evolutionary bioscience researcher specializing in SARMs (Selective Androgen Receptor Modulators). His extensive work, characterized by cutting-edge research and practical training advice, has made Sarms.io a leading source for accurate, credible information on performance enhancers. With a dedication to improving the understanding and application of SARMs in optimizing human performance, his contributions have not only expanded public awareness but also shaped the conversation around these substances. Chris's pursuit of knowledge and commitment to sharing it continue to inspire many in their fitness journeys.

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