Why is Menthol So Cool?

Ethos Ho, BSc Pharm Candidate

What is Menthol?

Menthol is one of the most well-known additives used in consumer products. It’s added to confections such as chocolate, oral-care products and medicinal products for its cooling and biological effects. The aromatic plant from which menthol is derived has been shown to exhibit various properties, including antibacterial, antifungal, antipruritic (itch relief), anticancer, and analgesic (pain relief) activity. Additionally, menthol is one of the most commonly used agents in pharmaceuticals to enhance the delivery of drugs into the skin.¹ Naturally, menthol is found in both prescription and over-the-counter products for a host of conditions including:²

• Gastrointestinal disorders
• Common cold
• Respiratory disorders
• Musculoskeletal pain

Today’s article will focus on how menthol works in relieving pain, and in our future articles, we’ll discuss the use of menthol in other medical conditions. So, stay tuned for more cool articles in the future!

How Does Menthol Relieve Pain?

If you ever browse through the pain reliever section of a pharmacy, you’ll likely see that menthol is an ingredient in many of the topical pain medications (ointments, creams, gels, etc.). Why is that? Menthol is known for its counter-irritant and local anesthetic properties. In concentrations of 1% or less, menthol acts as a local anesthetic, while at concentrations of 1.25% and 16%, it acts as a counter-irritant. However, concentrations of 30% and above can induce cold pain.³

Its local numbing effects occur when menthol blocks the transmission of pain in the nerves and muscles.³ On the other hand, its counter-irritant property comes from the “cooling effect”, where menthol activates pain receptor before desensitizing them. This is the reason why we feel the slightest sensation of pain before we see any pain relief.²

The exact mechanism by which menthol produces analgesia is still unknown. One theory suggests that it’s likely menthol’s ability to activate and/or inhibit certain receptors that are associated with pain.³ Another suggests that it may be linked to menthol’s ability to increase blood flow at the site of application,^2,3 thereby increasing the skin temperature and relieving pain similar to that of heat therapy.³

How Safe is Menthol?

Menthol is generally considered a safe product that’s used in numerous consumer products. Concentrations up to 16% has been approved by the FDA for over-the-counter topical use, and its safety profile has been well-established. However, concentrations up to 40% have resulted in skin redness and irritation and spontaneous burning, and minor and serious allergic reactions have been associated with menthol use.³

The Bottom Line

Menthol is a chemical found in aromatic plants that have shown to exhibit various medicinal properties. It’s not a surprise to see menthol used in a wide-range of products, ranging from foods, cosmetics to medicines. One popular medical condition that menthol is used for is pain, where it offers numbing or counter-irritant properties based on its concentration. Although its underlying mechanism is still unclear, it’s believed to be related to inhibition of pain transmission in the nerves and certain receptors that respond to harmful stimuli. It’s also believed to help increase blood flow to the application site, causing an increase in temperature which then relieves pain. Evident by its use in many consumer products, menthol is a safe compound; however, redness, spontaneous burning, and allergic reactions are some things to watch out for when using menthol.

As always, we hope you took away something valuable from this piece. If you have any questions or concerns regarding this article or others, feel free to reach out to us on Instagram, Facebook, or at ask@orbishealth.ca with your feedback. We’d love to hear from you.

RESOURCES

1. Kamatou, G., Vermaak, I., Viljoen, A., & Lawrence, B. (2013). Menthol: A simple monoterpene with remarkable biological properties. Phytochemistry, 96, 15-25. doi: 10.1016/j.phytochem.2013.08.005
2. Pergolizzi, J., Taylor, R., LeQuang, J., & Raffa, R. (2018). The role and mechanism of action of menthol in topical analgesic products. Journal Of Clinical Pharmacy And Therapeutics, 43(3), 313-319. doi: 10.1111/jcpt.12679
3. Patel, T., Ishiuji, Y., & Yosipovitch, G. (2007). Menthol: A refreshing look at this ancient compound. Journal Of The American Academy Of Dermatology, 57(5), 873-878. doi: 10.1016/j.jaad.2007.04.008