Overview of Andarine (S4)

Andarine, also known as S4, is a first-generation SARM that offers a unique balance between muscle mass gain, strength improvement, and body fat reduction. The result is a more defined, dense, and vascular physique, particularly appreciated during cutting phases.

Compared to most other SARMs, S4 causes significantly less suppression of endogenous testosterone production, a feature that makes it interesting considering its high efficacy. A known but completely reversible side effect is temporary vision changes during use. Another positive aspect of andarine is its potential protective effect on the prostate.

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What is Andarine (S4)?

S4 (Andarine) was initially developed by GTx and was one of the first SARMs to demonstrate real anabolic effects. Clinical trials were halted, probably due to the visual disturbances observed (yellow tint and reduced night vision), which, however, disappear quickly after discontinuation.

Although it has never been marketed as a drug, andarine is still used for fat loss and body recomposition, similar to Ostarine. In terms of potency and hormonal suppression, S4 ranks between Ostarine and LGD-4033: stronger than Ostarine, but less aggressive than LGD.

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Scientific evidence

Studies conducted on animal models for periods of up to 120 days have shown that andarines (S4) are capable of:

• increase skeletal muscle mass

• improve strength

• reduce body fat

• increase bone mineral density

A potential effect of preventing bone resorption has also been observed, making S4 interesting for skeletal health as well.

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Main effects of Andarine (S4)

• Increased muscle mass: promotes lean and defined muscle development

• Increased strength: many users report noticeable improvements in lifting capacity

• Body fat reduction: ideal for cutting phases

• Increased bone density

• Prostate protection: S4 acts as a partial agonist of androgen receptors in the prostate, blocking the action of DHT without stimulating its growth.

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Testosterone suppression

Like all SARMs, andarine suppresses natural testosterone production. However, S4 is less suppressive than compounds such as LGD-4033 or RAD-140.
To limit the hormonal impact, many users combine it with:

• SERMs (e.g., clomiphene or tamoxifen)

• or testosterone or gonadotropin during the cycle

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Effects on the liver and lipid profile

No significant increases in liver enzymes have been reported with S4, but high doses may increase the risk of side effects.
Like other SARMs, andarine may affect the lipid profile:

• reduction in HDL

• increase in LDL

Regular blood tests are recommended during the cycle.

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Visual disturbances

One of the most well-known side effects of S4 is temporary vision changes:

• yellowish tint

• reduced night vision

• difficulty adjusting to light

These effects are dose-dependent and disappear quickly after discontinuation. If they occur, it is recommended to reduce the dosage.

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Half-life

• 4–6 hours

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Recommended dosages of Andarine (S4)

• Beginners: 20 mg

• Average dosage: 25–75 mg

• Recommended maximum: 100 mg

• Women: 10–20 mg