Menthol is a chemical compound that can be naturally found in peppermint and other mint plants, or it can be synthesized in a lab. It is used in a variety of products, including toothpaste, mouthwash, cough drops, cold remedies, lip balms, body balms, and pain creams. The effects of menthol depend on how it is used:

• Topical use: When applied to the skin, menthol produces a cooling effect that can initially stimulate nociceptors and then desensitize them, acting as a counter-irritant. It can also activate central analgesic pathways and reduce minor aches and pains of the muscles/joints. Menthol can be used in numerous ways, such as a cooling patch for headaches or a soothing skin lotion to treat overexposure from the sun, itching, and inflammation.

• Inhalation: When inhaled, menthol can reduce airway pain and irritation from cigarette smoke and suppress coughing, giving smokers the illusion of breathing more easily. However, it can worsen congestion and cause inflammation in the airways.

• Ingestion: Concentrated amounts of menthol can cause systemic toxicity, including seizures, coma, and death. Menthol can also cause eye and skin irritation, and high-percentage menthol products applied to the skin can cause chemical burns.

Menthol works by activating transient receptor potential melastatin-8 (TRPM8) channels, which are responsible for the cooling sensation and reduction in pain associated with a wide variety of pain(ful) conditions. Menthol also reduces the metabolism of nicotine and enhances its presence in the lungs, which can make it harder to quit smoking. Despite what some marketing messages may suggest, menthol cigarettes offer no health benefits compared to non-menthol cigarettes.