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S-4 (Andarine) – a comparison to Winstrol

s-4 andarineFormula: C19H18F3N3O6
Mol. mass: 441.357 g/mol

Half life: 2.6 hours
Chemical name: S-3-(4-acetylaminophenoxy)-2-hydroxy-2-methyl-N-(4-nitro-3-
Drug name: Andarine

Firstly my experiences with this compound.

I have actually used Andarine a couple of times, just so everyone knows exactly what Andarine (s-4) is, here is some info on it:

It is a sarm, a selective androgen receptor modulator and one of the sarms currently being studied (s4 studies have been stopped due to some toxic effects of the metabolite M1 that binds to the occular receptor). S-4 is the weakest in anabolic activity, but one of the most androgenic, being 1/3 as strong as testosterone at binding to the androgen receptor.

Don't look at the info on Wikipedia as uneducated half wits write so much misleading information, half the stuff is wrong, s-4 does not reduce the size of the prostate; in fact, it will, over time, enlarge it, and it does cause some suppression though its very mild.

The best part of s4 is the fact that it causes a drying out of the muscle and the skin surrounding it, and in turn it binds very well to the androgen muscle receptors, hardening and sharpening the muscle, so towards the end of a cycle it would prove to be very effective. It could possibly be used as a pre-contest hardener combined with other muscle hardening compounds.

SARMS s-4 causes significant weight loss by binding to the androgen receptors - it allows fat to be oxidised, and it displays potent nutrient partitioning affects, causing more calories to be used to build and repair muscle. In addition, it has mild anti-oestrogen qualities, and will lower oestrogen over a 4 week period. Recovery from an s4 cycle is pretty straight easy, so despite the mild suppression s4 is still a very useful SARM.

UPDATE: ( after continued experimentation and eye testing I have had no ocular impairment and no reduction in eye strength or eyesight)

S4 comparisons

As a comparison, I would compare s4 to winstrol but without the binding to the scalp, or any real changes to our cholesterol. Interestingly, I asked for one client to use s-4 to help with gynecomastia, as its androgenic. Since it binds to the androgen receptors, it seemed feasible, and DHT being a potent anti-estrogen, it seemed a logical conclusion to draw.

However, no changes were seen in this trial during the 30 days of daily dosing, but that trial will continue.

UPDATE: ( After a new protocol that I will outline later on in this article, gynecomastia (gyno) was reduced markedly with S-4)

sarms s-4 chemical structure

Fig 1. S-4 (Andarine) Chemical Structure

Russianstars cycle results

I used 50mg the first week, 60mg the second, 70 the third, 100 the fourth, 125 the 5th week, here are my results.

Week 1: 50mg s4, no gains, noticed increase in energy, no sides.

Week 2: 60mg, increased strength in the gym, great sense of well being, increased libido, no sides.

Week 3: 70mg, +1lb in weight, signs of fat loss, and muscle hardening, yellow tint to my eyesight, problems adjusting to light and dark.

Week 4: 100mg +1lb, big strength and endurance increase, no night vision, very sore eyes, black circles under my eyes.

Week 5: 125mg +1.5lb, severe muscle hardening, looks like I'm on Winstrol and Anavar in the 5th week of a cycle, permanent yellow tint in the day to my eye sight, no night vision, tremendous muscle endurance, increased strength, but sides far out weigh the benefits at this dose.

BUY S-4 (Andarine) @ SARMS1.COM

s-4 (andarine)

BUY S-4 (Andarine) @ SARMS1.COM


Eye sight returned to normal four days after finishing the cycle, no changes to blood pressure or cholesterol were noted. Muscle gained was a very lean 3.5lbs, I've kept them ever since, and the muscle hardening has lasted also. It holds remarkable promise, but I'm going to put off using it again as I'm going to be doing LGD-4033 and peptide testing.

How to use S4 safely

If you were to run this SARM, I would use it 5 days on 2 off at 50mg. This should negate any sides. If you go above 50mg you will lose some night vision, and if you don't the S4 is of poor quality. S-4 has a very short half life, 2.6 hours, so would make it perfect to use as a pulse, 3 times a week 2 hours before training should give excellent strength and hardening results. Both those protocols will reduce the yellow eye, and night vision problems. Remember, a PCT (post cycle therapy) should be always carried out after using S4.

How to use S4 to reduce gynecomastia (gyno)

Running 20mg a day 6 days on 1 off for 6-10 weeks not only reduces body fat, but it has been used by me in conjunction with the only other compound I've ever seen reduce gyno – Letrozole (femara). Using 0.5 mg of Letrozole 3 x a week in conjunction with the S4 shows great promise in reducing steroid induced gynecomastia (gyno).


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Written by
Russian Star is an industry leader in peptide design and development. He is a fitness mentor with a Masters degree in molecular chemistry, he's working on his PhD in biochemistry.


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    Hello Russian Star, I am interested in getting the cutting stack GW501516 and S4 and stacking with liquidex A.I and HCGenerate for four(4) weeks minimal to asses my body progress and reactions to them.

    I would like to know how do you know the quality and purity of these sarms at this website. Did you purchase your SARMS from Evolutionary .org and do you have any advice for me. Help please, thanks.

    STATS;42 yrs, 230lb bdf% 18-20, 5’9′

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    Also I see that you have made some good progress yourself with the S4, congratulations to you. Did you experience any side effects such as eye irritations and or yellow tent at the 20mg a day for the 6 weeks and what is your recommendations for me..

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    Also Russian Star on some of these SARMS the websites it says NOT FOR HUMAN USE. what does that mean. Not sure please explain ,just being cautious.

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    Great article! Especially your last paragraph “How to use S4 to reduce gynecomastia (gyno)”. What would you recommend for pct? Have you gotten anymore detailed results from this? Also would you recommend splitting s4 up twice a day because of the half life?

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