What is Icy Hot (menthol or capsaicin)?

What is Icy Hot?

Icy Hot is an over-the-counter topical analgesic product containing menthol and/or lidocaine that provides a dual sensation of cooling followed by warming to help relieve pain. 1, 2

Composition and Formulations

• Icy Hot is available in various formulations including creams and patches containing active ingredients such as menthol (1%) and lidocaine (4%) 2
• It is manufactured by Sanofi Consumer Inc. and is commonly used as a topical pain reliever 1
• The product creates a counterirritant effect through its active ingredients, particularly menthol 3

Mechanism of Action

Menthol Component

• Menthol works as a selective activator of transient receptor potential melastatin-8 (TRPM8) channels, which creates the cooling sensation 3
• It acts as a counter-irritant by first stimulating nociceptors (pain receptors) and then desensitizing them 3
• The cooling effect is followed by a warming sensation, creating the characteristic "icy hot" feeling 4
• Menthol may also activate central analgesic pathways when applied topically 3

Lidocaine Component

• Some Icy Hot formulations contain lidocaine (4%), which is an amide local anesthetic 2
• Lidocaine blocks sodium ion channels required for the initiation and conduction of neuronal impulses, resulting in local anesthesia 1

Clinical Effects and Application

• When applied to the skin, Icy Hot products initially decrease skin temperature by approximately 1.7-2.1°C and muscle temperature by 1.0-1.3°C 4
• Unlike heat wraps that increase tissue temperature, Icy Hot products generally produce a net decrease in skin blood flow 4
• Topical application of menthol can reduce perception of pain and enhance sensation of cooling during exercise or physical activity 5

Clinical Uses

• Icy Hot is commonly used for temporary relief of minor aches and pains associated with:

  • Arthritis 1
  • Muscle strains and sprains 1
  • Back pain 1
  • Joint pain 1

• It has been mentioned in clinical guidelines as a potential topical treatment option for certain conditions:

  • For erythromelalgia (a rare condition causing burning pain and redness in extremities) 1
  • For osteoarthritis pain management, particularly in the knee 1

Important Considerations and Cautions

• Menthol-containing products may cause initial stinging or burning sensations when first applied 5, 6
• These products should not be used with heating pads or immediately before/after hot showers 1
• Should be applied only to intact skin and avoided on wounds or damaged skin 1
• Patients should wash hands thoroughly after application to avoid accidental contact with eyes or sensitive areas 3
• May not be suitable for all patients, particularly those with certain skin sensitivities 6

Efficacy Compared to Other Treatments

• Clinical guidelines suggest that topical analgesics like Icy Hot may be preferred over systemic treatments for localized pain due to their favorable safety profile 1
• For osteoarthritis pain, topical treatments are recommended as first-line pharmacological options, especially when only a few joints are affected 1
• In studies comparing different topical analgesics, menthol-containing products like Icy Hot showed different physiological effects than heat wraps, with heat wraps providing greater tissue warming and increased blood flow 4