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UPDATED August 2015
Massage therapists typically rely on muscular relaxation, stretching, mobility and circulation enhancement to achieve pain relief. All kinds of healthcare practitioners – ranging from osteopathic physicians, to chiropractors, to acupuncturists, to massage therapists – include using topical applications as an adjunct to their primary modality of delivering pain relief. While many natural substances have been hailed for their pain relieving properties, two substances standout. That is why wintergreen and menthol are the star ingredients in a wide range of topical pain-relieving products.
On a molecular level, American researchers have uncovered one of the reasons behind the success of gels using wintergreen and menthol in battling pain. Application of either compound to the skin causes a visceral temperature change. This is apparent when a product containing either substance, such as Ben-Gay or Icy Hot, is applied to the skin and causes a cold or hot sensation. According to Ardem Patapoutian, associate professor at Scripps Research and Genomics Institute, “Because our ability to sense temperature is closely linked to our ability to sense pain, it is not surprising that the misregulation of temperature-activated ion channels can result in chronic pain syndromes.”
Our experience of temperature is determined by long, specialized neurons connecting to the brain through the spinal column. These neurons have nerve endings embedded in our skin, where they detect temperature and communicate this information to the brain. The combination of pain and temperature sensation is well established. Try holding an ice cube where it’s so cold that it hurts. This is a logical protective mechanism where extreme freezing or scorching hot temperatures depend on our ability to sense pain and react accordingly. In the researchers’ identification of cold-sensing nerve receptors, it appears that those same receptors communicate pain. This could be the molecular basis for understanding how wintergreen and menthol ease pain. By stimulating temperature nerve receptors with a specific intensity, these topical ingredients may block or interrupt the pain signal.
The natural consequences of tissue injury, pain and tenderness typically abate as healing progresses. Unfortunately, some individuals experience pain without an obvious injury or suffer protracted pain that persists for months or years after the initial injury. This pain condition is typically considered to be neuropathic, accounting for a large number of people presenting to pain clinics with chronic, non-malignant pain. Rather than the nervous system functioning properly to sound an alarm regarding tissue injury, neuropathic pain occurs when the peripheral or central nervous systems malfunction and become the cause of the pain.
As a product of a constantly firing central nervous system, neuropathic pain is most likely to benefit from the activation of temperature nerve receptors. This is one way of understanding why topically applied menthol and oil of wintergreen relieve chronic pain.
The main chemical constituent of wintergreen oil is a natural anti-inflammation compound, methyl salicylate. The body converts methyl salicylate to salicylic acid, otherwise known as aspirin. When applied topically, oil of wintergreen possesses two well-documented advantages over aspirin, with comparable anti-inflammatory results:
- A topical application of methyl salicylate does not result in the stomach irritation or liver toxicity commonly associated with oral anti-inflammatory medication.
- Methyl salicylate is better absorbed by muscle tissue than blood. Therefore, the active component is more effective when applied to the skin than where it can be filtered out by the blood supply.
Menthol is a compound primarily derived from peppermint or other mint oils. It is a waxy, crystalline substance that is solid at room temperature. Similar to methyl salicylate, menthol is an anti-inflammatory and chemically triggers cold-sensitive receptors in the skin, causing the characteristic cooling sensation.
A study conducted on people with osteoarthritis showed improvement in the severity of joint pain when applying cetylated fatty acid cream topically. When menthol was added to this cream, pain and functional performance by people with knee, wrist and elbow osteoarthritis was even further reduced by a statistically significant margin.
Topical Application Cautions
There are several reasons why you should proceed with caution when using preparations with menthol or methyl salicylate, including skin irritation. First and foremost, thorough handwashing after application is essential to prevent contamination in unwanted areas. To avoid skin sensitivity and magnification of systemic absorption of menthol or wintergreen, do not cover the affected area with a tight bandage, use in conjunction with a heating pad or apply after strenuous exercise. Because methyl salicylate readily penetrates the skin after topical application, it should not be used on scraped, irritated or broken skin or near the eyes or mucous membranes. Due to the possibility of percutaneous absorption, methyl salicylate should be used with caution in individuals who are sensitive to aspirin or products containing aspirin.
Putting it to Use
Applying topical preparations, including the ingredients oil of wintergreen and/or menthol, can provide clients who experience chronic pain an additional layer of relief. While healthcare professionals have relied on these ingredients for years, understanding why they work may encourage their use by more therapists. Listed below are some tips for massage therapists looking to include topical applications in their treatments. Seek products with ingredients that:
- Come from a reputable supplier
- Are not greasy
- Will not stain clothing
- Have been recommended by other therapists/clients
- Have a liberal return policy
Try a few different formulations on clients with chronic pain, being sure to check for skin sensitivity, until you find one that works. By providing relief from every possible angle to yield the highest chance of success, it only makes sense to include topical pain relievers in conjunction with massage therapy.
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