S4 X


25mg – 60 capsules

S4 X, also known as S4, Andarine,  or Acetamidoxolutamide. It is a selective androgen receptor modulator (SARM) that functions as both a muscle mass developer and a fat burner.



Only a small effect on the growth of major organs such as the prostate, heart, liver and kidneys

no significant changes in the LDL/HDL ratio which means it has an incredibly low cardiovascular risk.

Will not change secondary sex characteristics. This means no man boobs, developing in the post cycle recovery stage

No decrease in testosterone during post cycle recovery

Short post cycle recovery- roughly 4 weeks

Simultaneously increases muscle mass and reduces body fat.


S4 X functions as a SARM and SARMs work by binding to the androgen receptor. In binding, S4 X changes the structure of the receptor and encourages the growth of bone and muscle tissue. This effect is similar to other supplements, but S4 is extremely selective in its anabolic activity.


S4 X causes an increase in anabolic hormones which allows  more protein to be used for muscle building which thereby increases muscle mass.

Studies show that Andarine has roughly 30% of the overall strength of testosterone when binding to the androgen receptors which is a significantly high percentage. Using S4 allows you to desensitizes the androgen receptors which allows for testosterone to be focus on building muscle and burning fat.


S4 X is one of the most extensively researched supplements out there. The majority of these studies have been to determine the efficacy of Andarine as a treatment for muscle wasting, osteoperosis, and hypogonadism.

Studies found that S4 X not only maintains lean muscle, it actually promotes growth. One study saw muscle mass increase by 1-1.5 kg in just 90 days, without any changes in the subject’s exercise routine or diet. The study also saw a decrease in body fat thanks to the fact that S4 X breaks down stored fat. Throughout the studies, there have been no reports of any aderse side effects from Andarine usage,


Andarine shares similar traits steroids like Anavar and Winstrol but it produces better gains without risk of adverse side effects.

S4 X reduces lipoprotein lipase which is an enzyme responsible for storing fat. S4 X breaks down stored fat converts it to an energy source. Reduced body fat can improve vascularity and give you a more chiseled look overall. One of the great things about S4X is that is does not cause joint pain when lifting, and it doesn’t induce water retention which many other supplements do.


S4 X is not the most effective SARM for bulking – it’s beat out by both LGD X and RAD X. S4 X does have the unique benefit of better utilizing the calories that are consumed when bulk which will allow you to maintain a lean look even when adding on bulk.


Unfortunately. Andarine can cause issues with the user’s eyes. Many people report experiences of night time blindness or altered colour perception while using this supplement. S4 X does bind to the eye receptors, which is likely the root of these issues. The good news is these conditions are not permanent and the eyes will return to a regular state eventually.


A standard dosage for S4 X is 2 doses of 25mgs every day for 12-16 weeks. S4 X does not need to be taken more than twice a day and it’s best consumed with a regular meal. Start out with a 4 week cycle then allow your body to flush it for 4 weeks before continuing.

You will experience diminishing returns on your gains if you use over 75mgs of S4 X on a daily basis for more than 16 weeks. Taking higher doeses will not have additional side effects, but you may have les free testosterone during the post cycle flush!

Andarine is at its best when it’s combined with other SARMs. It has great  synergy with both MK-2866 and LGD X as these SARMs suppress testosterone levels at higher dosages unless combined with S4 X.


2008 saw SARMs receive a sweeping ban enacted by the WADA, meaning that professional athletes cannot legally take it, Amateurs who aren’t looking to go competitive are more than free to use any SARM including S4 X.


Goal                                                                                       Dosage                                                 SARMS That Stack Well

Strength Gain (minimal gains in muscle mass)     50+mg/day for 6-8 weeks           N/A

Recomposition                                                                 50-75mg/day for 4-8 weeks        N/A

Cutting                                                                                50mg/day for 6-8 weeks               Ostarine & GW-501516


Available at Helixx Online