Andarine S4 25mg

Andarine (S4) was one of the earlier SARMs developed by GTx, the same company behind Ostarine. It shares the basic SARM profile -- androgen receptor agonism with selectivity toward muscle and bone tissue -- but has a pharmacological quirk that distinguishes it from most compounds in this class: it also binds, to some extent, to androgen receptors in the retina.

This visual side effect, reported by some research subjects as a yellow tint to vision or difficulty adapting to low-light conditions, appears to be dose-dependent and reversible upon discontinuation in reported cases. It's thought to arise from partial agonist activity at ocular AR, though the exact mechanism isn't fully established. For research design purposes, this characteristic makes Andarine a useful model compound for studying tissue-specific AR effects, including how partial versus full agonism differs across tissue types.

The anabolic profile in rodent studies is fairly well-characterized. Andarine shows muscle-sparing effects in castrated animal models, bone-protective effects in osteoporosis models, and the expected tissue selectivity relative to classical androgens. It's not as extensively studied in clinical trials as Ostarine, but it has been a valuable research tool for understanding SARM mechanism of action.

Research Applications

Andarine is used in studies of androgen receptor pharmacology, tissue-selective AR agonism, muscle and bone biology, and -- because of its ocular binding profile -- as a model compound for studying off-target AR effects. Its partial agonist characteristics make it interesting for mechanistic work comparing full versus partial AR activation.

Specifications

Storage

Store at -20°C in the original sealed vial. Stable for 24+ months under proper conditions. Minimize light exposure during handling and preparation.

Andarine S4 is supplied for laboratory research use only. Not approved for human use. Handle in compliance with institutional biosafety guidelines.