Menthol is a common ingredient in many over-the-counter remedies, often associated with a cooling sensation. This article explores how menthol may offer relief for coughs and examines the scientific understanding behind its effects.
How Menthol Works
Menthol, a compound found in mint plants, interacts with specific receptors in the body to provide a sensation of relief. It activates transient receptor potential melastatin 8 (TRPM8) channels, which are cold-sensitive receptors located in the throat and nasal passages. This activation creates a cooling sensation, which can make a person feel as though their airways are clearer, even if there is no physical change in airflow.
Beyond this cooling effect, menthol also possesses mild local anesthetic properties. This means it can temporarily numb nerve endings in the mouth and throat, soothing irritation and discomfort associated with a cough or sore throat. The combination of cooling and mild numbing contributes to the perception of relief.
Common Menthol Products for Cough
Menthol is available in various over-the-counter forms designed for cough relief. Cough drops or lozenges are a widely used option, where menthol dissolves slowly in the mouth, releasing its soothing and cooling properties directly to the throat.
Topical chest rubs, such as Vicks VapoRub, contain menthol along with other ingredients like camphor and eucalyptus oil. These rubs are applied to the chest and throat, allowing medicated vapors to be inhaled for relief. Vaporizers and inhalants also utilize menthol, often by adding a liquid solution to hot water to produce medicated steam that can be breathed in for temporary relief of cough and nasal discomfort.
Assessing Menthol’s Impact on Cough
Menthol primarily offers symptomatic relief rather than directly suppressing the cough reflex or addressing the underlying cause of a cough. Its cooling and mild anesthetic effects help create a perception of clearer airways and soothe irritated mucous membranes.
Scientific studies suggest that menthol can reduce cough sensitivity, particularly when inhaled. However, this effect is largely attributed to sensory perception rather than an objective reduction in airway resistance. Some research indicates that excessive use of menthol cough drops can be associated with more severe cough symptoms in some individuals. This suggests that while it provides temporary comfort, it does not cure the cough.
Safe Use and Precautions
When using menthol products for cough relief, it is important to follow dosage instructions provided on the product label. Overuse of menthol can lead to side effects, including numbness of the mouth or throat, and allergic reactions like rash, itching, or swelling. Skin irritation, such as redness or a burning sensation, can occur with topical application.
Specific populations should exercise caution. Menthol products should not be used in children under two years of age, as they can cause increased mucus production and respiratory distress in their smaller airways. Individuals with breathing problems like asthma or emphysema, or those with a chronic cough or a cough producing a lot of mucus, should consult a healthcare professional before using menthol. Persistent coughs lasting more than seven days, or those accompanied by fever, headache, rash, or worsening symptoms, warrant medical attention.