Camphor Induces Cold and Warm Sensations with Increases in Skin and Muscle Blood Flow in Human

Abstract

Application of camphor to the skin has been empirically thought to improve blood circulation. However, camphor's effects on blood circulation to the skin and on thermal sensation have not been well elucidated. In this study, we examined its effects on the quality of sensation as well as on skin and muscle blood flow in human. Nine adults (average age 37 9.4 years) participated in the study. Petroleum jelly containing 5%, 10%, 20% camphor, or 2% menthol was separately applied to the skin on the medial side of one forearm of each subject. Just after the application, camphor at each concentration induced a cold sensation in a dosedependent manner. Within 10 min, each subject reported that the cold sensation had faded, after which it was replaced by a warm sensation. As reported previously, a cold sensation was induced by application of 2% menthol, but the subjects did not adapt to that sensation. In addition, menthol did not induce a warm sensation at all. Application of menthol has been shown to increase blood flow in the skin. Finally, we measured blood flow in skin and muscle after the application of camphor or menthol. Application of camphor or menthol separately induced increases in local blood flow in the skin and muscle. The present results indicate that camphor induces both cold and warm sensations and improves blood circulation.

Menthol concentration in topical cold gel does not have significant effect on skin cooling

“…In contrast, Kotaka et al. reported that 2.0% menthol gel increased skin blood flow locally . Although we did not see effect on temperature in the surrounding areas, in three subjects we did observe skin temperature rise with 4.6% and 10.0% menthol gel areas after cooling menthol effect had ended.…”

“…In contrast, previous studies have reported that topical menthol ointments reduce arterial blood flow (8-10, 12, 14) which would implicate that menthol would affect the blood flow and temperature also at the surrounding skin areas. In contrast, Kotaka et al reported that 2.0% menthol gel increased skin blood flow locally (15). Although we did not see effect on temperature in the surrounding areas, in three subjects we did observe skin temperature rise with 4.6% and 10.0% menthol gel areas after cooling menthol effect had ended.…”

Comparison of two skin temperature assessment methods after the application of topical revulsive products: Conductive iButton data logger system vs contact‐free infrared thermometry

“…In group A, no interaction effect was found for skin temperature (F [11,2] = 7.204, P = .128, 2 partial = 0.975). A significant main effect for time (F [11,2] = 54.016, P = .018, 2 partial = 0.997), and no effect for device (F [1,12] = 0.031, P = .863, 2 partial = 0.003) was reported. Both skin temperature devices differed significantly at baseline (P < .001).…”

Topical patches as treatments for the management of patient musculoskeletal and neuropathic pain

“…Camphor has analgesic and anti-inflammatory properties and has been shown to activate heat-sensitive transient receptor potential (TRP) vanilloid, acts on TRPV1 and TRPV3 receptors. Levomenthol has been reported to have analgesic effects, including anesthesic action, acts on TRPM8 and TRPA1 receptors, secondary to the activation of endogenous opioid receptors [16,26].…”