Bemethyl, also commonly referred to in literature as bemitil, is an actoprotector drug which is also antihypoxant (combating conditions of hypoxia), antioxidant, and antimutagenic. Bemethyl is primarily classified as an actoprotector: a synthetic adaptogen with significant capacity to increase physical performance.

It is approved for use in Ukraine as a dietary supplement. Bemethyl is commonly used in preparing for international competitions by Ukrainian national sport teams.

Bemethyl is formulated as a hydrobromide salt. Its parent compound is 2-ethylsulfanyl-1H-benzimidazole.

Bemethyl also has a positive effect on metabolic processes, allowing adaptation to conditions causing frequent hypoxia, and the obtained effect is long-lasting and also occurs after the end of dosage.

Bemethyl has been shown to preserve both physical and mental capacity in high-altitude, low-oxygen environments, particularly by its effect in helping control excess serum levels of cholesterol and bilirubin, which are known to have negative effects especially during adjustment to high-altitude environments.

Bemethyl has also been shown to prevent permanent hearing loss and facilitate recovery of hearing after mine-explosion trauma, when treatment is initiated immediately after injury.

In one study, bemethyl was shown to prevent the mutagenic effect of white asbestos in mice and in cultured human whole blood.

A study using mice showed bemethyl to reduce mutation induced by certain mutagenic drugs.