Chapter 1. Intro

I am thrilled to bring you information on one of the more underrated and interesting SARMs (selective androgen receptor modulators). It is called Andarine (s-4) and it was in development with the hopes it would treat some medical issues. Today it is used by those in the fitness industry to give them an edge over their competition.

Chapter 2. Original development

Andarine (s-4) was originally developed by the drug company GTX Inc. The idea was to help with bone health, muscle wasting, and BPH (benign prostatic hypertrophy) which is an enlarged prostate. It was abandoned likely for economic reasons and because of the temporary vision side effects which I will discuss later in the article.

To confirm the bone anabolic effect, S-40503 was given to ovariectomized (OVX) rats for 2 months. The compound significantly increased the BMD and biomechanical strength of femoral cortical bone, whereas estrogen, anti-bone resorptive hormone, did not…which had unique tissue selectivity with high potency for bone formation and lower impact upon sex accessory tissues. (1)

Since then it has been sold by research chemical companies to those in fitness as a performance-enhancing drug.

Chapter 3. Working in the body

Just like every other SARM (selective androgen receptor modulator), Andarine (s-4) works by attaching to androgen receptors selectively. According to the studies, we also know that it is milder than others in its class because it is a partial agonist of the androgen receptor. However, don’t let that fool you into thinking it won’t still give you some solid results.

Another cool thing Andarine (s-4) does is that studies showed it had anti-DHT (dihydrotestosterone) effects in the body. This means it will block sex hormones which cause things like the shedding of head hair and enlarged prostate (similar to 5a reductase inhibitors like finasteride and dutasteride). However, and this is huge, it does NOT carry over the negative side effects of those nasty drugs. So you do not have to worry about libido problems and feeling crappy.

S-4 acted as a full AR agonist in the levator ani muscle, as indicated its ability to fully maintain the muscle to that of control level. However, S-4 acted as a partial agonist in the prostate (E_max = 35% of control values), indicating that S-4 was potent and efficacious in anabolic tissues but not in androgenic tissues. (2)

andarine results before and after

Chapter 4. Comparing to anabolic steroids

Andarine (s-4) is very mild, so do not expect crazy changes in weight, strength, and aggression like you would from using anabolic steroids. However, the benefits of using it are stronger bones, lean muscle mass, and mild strength gains. Users also say, when properly stacked, it is great for fat loss too while in a carbohydrate and calorie deficit.

Another benefit is that it does NOT give you the following side effects, while anabolic steroids CAN:

Enlarged prostate
Shedding of head hair
Aggression issues
Liver and kidney strain
Heart strain
Mood swings
Insomnia
Sometimes permanent dysfunction of reproductive health
The shutdown of the pituitary glands
Estrogenic issues like water retention and gynecomastia

Chapter 5. Use in athletics

There are many ways you can utilize Andarine (s-4) to your advantage. You are most certainly able to run it solo, but many athletes like to use it as part of a stack for maximum synergy. You want to keep the cycle length to around 8-12 weeks on average, and not exceeding 16 weeks. Here are some ideas depending on your goals:

Section 1. Powerlifters:

Andarine (s-4) mysteriously is one of the best SARMs (selective androgen receptor modulators) for strength. I like to stack 50-75mgs per day with 10mgs per day LGD4033 (Anabolicum). For those who use anabolic steroids, you can also add it in at the same dosage. A good stack is Andarine (s-4) + Trenbolone at 250mgs per week, you should hit personal records on that cycle.

Section 2. Those seeking to lose body fat:

Andarine (s-4) also seems to work well for cutting down body fat while in a deficit. A popular cutting stack is using 50mgs a day + 20mgs per day of Cardarine (GW501516). Those who use steroids can add in Anavar at 50mgs per day or Winstrol at 25mgs per day.

Section 3. Bodybuilders trying to recomp:

Andarine (s-4) is also great at adding lean muscle mass while also losing body fat. This concept is called “recomping the body” and it is very difficult to do without the help of compounds like these. A good stack for this would be Andarine (s-4) at 50mgs per day + 20mgs per day of Cardarine (GW501516) + 10mgs per day LGD4033 (anabolicum). Those who use steroids can use the same dosage of Andarine (s-4), along with 500mgs a week of Primobolan + 175mgs a week of Testosterone Cypionate.

Another good reason to always use Andarine (s-4) with your anabolic steroid stack is that it will help prevent head hair loss and enlarged prostate. If you notice yourself peeing a lot on cycle it probably means your prostate is getting too big, which is not a good thing.

Chapter 6. Side effects

Andarine (s-4) does not aromatize into estrogen at all, is not androgenic, and is only slightly suppressive of the pituitary glands. Due to the suppression, a mini-post cycle therapy is recommended to help with recovery. A simple way to do it is use hcgenerate ES for 4-8 weeks.

The one side effect that Andarine (s-4) has that makes it very unique is that it will attach slightly to androgen receptors which affect our eyes. What happens is you will notice a yellow tint when changing different lit rooms, or when waking up in the morning. This is not universal and is also dependent on the dosage you are using. Also, keep in mind it is temporary, and once you stop using it the issue will go away after a few days.

Chapter 7. Half-life and detection times

Andarine (s-4) half-life is under 7 hours. This means a dosing schedule where you split your dosages AM and PM is a smart idea to keep stable levels.

Detection times are unknown but based on user experiences it should be undetectable after 3 weeks. If you are a tested athlete and it is still in your system when you are checked for doping, you will fail because it is banned in all organized leagues and the Olympics.

Chapter 8. Dosages

Men will run Andarine (s-4) at 25-75mgs per day. Women can run it at 12.5-25mgs per day.

Chapter 9. Where to Buy Andarine

Andarine (s-4) was never approved for use, however, companies that cater to athletes are still producing it. Beware of random sources selling it, because they are known to lace the product with prohormones to fool the buyer. You can check out our forums at elitefitness.com and evolutionary.org to find an approved source that carries it.

Chapter 10. References

Hanada K, Furuya K, Yamamoto N, et al. Bone anabolic effects of S-40543, a novel nonsteroidal selective androgen receptor modulator (SARM), in rat models of osteoporosis. Biol. Pharm. Bull. 2003;26:1563–1569. The first report of the tetrahydroquinoline-based SARMs and the effects of a SARM on bone.
Discovery AND Therapeutic Promise OF Selective Androgen Receptor Modulators
Jiyun Chen,1 Juhyun Kim,1 and James T. Dalton1