What is Andarine?
Andarine, also S4 or S-4, is one of the older SARMs from the aryl-propionamide family. It was one of the first to be clinically evaluated. Clinical development was later not pursued.
Andarine is known mainly for a characteristic vision effect: a yellow tint to vision and worse night vision, occurring dose-dependently. This is not a myth but is reported consistently.
How it works
Andarine binds the androgen receptor and activates it with tissue preference in muscle and bone. In animal models it was associated with maintaining bone density and reducing body fat.
The vision effect likely relates to how Andarine binds certain structures in the eye. It is reversible after stopping but bothersome during use.
How to take it
Oral, often split because of the short half-life.
- Half-life only around 4 hours, so often morning and evening.
- With some water, with or without food.
- Cycles are usually kept short.
Dosing
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What the research shows
A preclinical study (Kearbey, 2007) showed in ovariectomized rats that S-4 maintained bone density and bone strength while reducing body fat. That is a solid animal result.
Solid modern human data on muscle building in healthy people are scarce, clinical development was discontinued. The Solomon review (2019) places Andarine in the SARM context.
Side effects
- Characteristic vision effect: yellow tint, worse night vision, dose-dependent and reversible after stopping.
- Dose-dependent suppression of the testosterone axis.
- Falling HDL values.
Practice
- Stay low, the vision effect scales directly with the dose.
- Short cycles, then a break.
- Banned in official competition and detectable (WADA S1.2).
Storage
Store dry, cool and protected from light, out of reach of children. Keep the original container closed and mind the expiry date.