Dr. Robert Topp and his colleagues at the University of Louisville have studied the effects of Biofreeze® pain reliever on blood flow. Olive et al. (2010) showed that Biofreeze gel applied to the forearm of young healthy subjects resulted in similar decreases in blood flow as crushed ice. In addition, the reduced blood flow occurred much quicker with Biofreeze than with ice.
Different Biofreeze products contain different levels of menthol, depending on the delivery mechanism. Dr. Topp and his colleagues wanted to see if there was any difference in blood flow reduction between Biofreeze wipes containing 10% menthol, compared to 3.5% menthol in Biofreeze gel applied to the lower extremity after brief, intense resistance exercise.
16 young, healthy subjects were assessed for popliteal blood flow in both the left and right knees before performing 3 maximal repetitions of isokinetic knee flexion and extension at 90 degrees per second. Immediately after the exercise, the subjects received one of 3 randomized conditions on the right leg only: gel, wipe, and no treatment (control). Blood flow was measured again, 5 minutes after the treatment was applied. Each subject was tested once weekly until they had completed all 3 conditions.
The researchers found that both the Biofreeze gel and wipe significantly reduced blood flow in both legs, while the control group increased in blood flow in their exercise leg. This finding of reduced blood flow in the untreated leg was interesting. The researchers suggested a possible central nervous system mechanism behind the role of menthol in reducing blood flow. In conclusion, both Biofreeze gel and wipes reduce arterial blood flow immediately after brief intense exercise.
REFERENCE: Topp R, et al. 2011. Effect of topical menthol on ipsilateral and contralateral superficial blood flow following a bout of maximum voluntary muscle contraction. Int J Sports Phys Ther. 6(2):83-91.