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MASS (S4) or Andarine, is an orally administered SARM. MASS (S4) is said to be the most potent SARM which helps sustain lean muscle mass while stimulating fat elimination at the same time. MASS (S4) is an orally partial agonist for androgen receptors. Carrying this quality allows MASS (S4) to maintain and add lean body mass whilst avoiding negative side effects.

When being compared to testosterone and other forms of steroids, the advantages of SARMS like MASS (S4), is they do not have androgenic activity in non-skeletal muscles meaning little to no side effects. MASS (S4) is often thought of as one of the stronger SARM's, in terms of the many capabilities it has. It is a lean body mass builder, as well as strength and vascularity enhancer.


Concentration: 50mg/mL

Volume: 30mL

A 50mg (1ml) dosing protocol for 6-8 weeks is ideal for most purposes for the majority of users. Each bottle has 30ml with an average dose been around 1ml (1 full dropper squirt). Each bottle lasts for around 30 days.

Recommended Combinations

1. Endurance: You can stack MASS (S4) at a low dose with MELT (SR-9011) at 20mg per day for an increase in endurance.

2. AUS LABS CUT STACK: The best cutting stack would be the combination of 20mg of MELT (SR-9011) with 50mg of MASS (S4). This combination is well known as a potent ‘cutting’ stack.

3. Anabolic Steroid Stack: Stacking MASS (S4) as part of an anabolic steroid cycle is a good way to help increase strength and lean muscle mass without giving additional side effects to your cycle.

4. As a Stand Alone: MASS (S4) used by itself at 50-75mg. It is, in my opinion, one of the best SARM’s for increasing strength quickly. You will be moving more weight within 1-2 weeks, and the side effects will be minimal.

5. AUS LABS TRIPLE STACK: If you want to gain lean muscle and loose fat at the same time, MASS (S4) stacks beautifully with MELT (SR-9011) and GAIN (LGD-4033).

Ingredients/ HPLC Purity Report

MASS (S4): (2S)-3-(4-acetamido-phenoxy)-2-hydroxy-2-methyl-N-(4-nitro-3-trifluoromethyl-phenyl)-propionamide propylene glycol, ethyl alcohol and peppermint oil.

Please email [email protected] for the latest HPLC purity report.


Cool and dark space like a cupboard or pantry.

Medical Referances

  1. Schragl, KM( 1 ), Enev, VS( 1 ), Gaertner, P( 1 ), Forsdahl, G( 2 ) & Gmeiner, G( 2 ) n.d., ‘Novel pathway for the synthesis of arylpropionamide-derived selective androgen receptor modulator (SARM) metabolites of andarine and ostarine’, Tetrahedron Letters, vol. 54, no. 18, pp. 2239–2242
  2. Pubmed (2016).Investigation of the selective androgen receptor modulators S1, S4 and S22 and their metabolites in equine plasma using high-resolution mass spectrometry.
  3. De Rijke (2017). Selective androgen receptor modulators: in vitro and in vivo metabolism and analysis.

No statements made on this page have been evaluated by the Bundesministerium für Gesundheit (BMG) or the Therapeutic Goods Administration (TGA). These products are not intended to treat, cure or prevent any disease or illness. All products are strictly for research purposes only. Please refer to the TERMS OF USE for more information.

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