24Dinitrophenol

2,4-Dinitrophenol (2,4-DNP) is an organic compound with a phenolic core bearing nitro groups at positions 2 and 4. Its formula is C6H4N2O5. It appears as a yellow crystalline solid, sparingly soluble in water and more soluble in organic solvents. It is primarily used as an industrial intermediate in the manufacture of dyes, pigments, and other organic chemicals, and is encountered mainly in laboratory and manufacturing settings.

Historically, 2,4-DNP was marketed in the 1930s as a weight loss agent because it uncouples oxidative phosphorylation, increasing metabolic rate and body heat. Due to severe adverse effects, including hyperthermia, tachycardia, dehydration, and death, it was withdrawn from medical use and is now illegal for human consumption in many countries. Today it remains a regulated chemical, restricted to industrial and research contexts.

Mechanism of action: 2,4-DNP acts as an uncoupler of oxidative phosphorylation by shuttling protons across the mitochondrial inner membrane, dissipating the proton gradient and causing energy to be released as heat rather than stored as ATP. This can lead to rapid overheating and a range of systemic toxic effects.

Hazards and safety: It is highly toxic and potentially fatal if ingested, inhaled, or absorbed through the skin. Exposure can cause fever, tachycardia, sweating, nausea, liver and kidney injury, and death. It is toxic to the environment and aquatic life. Handling requires appropriate personal protective equipment, adequate ventilation, and strict institutional controls; improper use as a dietary supplement is illegal in most jurisdictions.