As of 2015, the ingredients of Biofreeze gel are listed at Drugs.com, and its active ingredient is menthol 3.5 percent, state Drugs.com and Biofreeze. The pain reliever's inactive ingredients include carbomer, glycerine, isopropyl alcohol, methylparaben and propylene glycol. The gel also contains water, silicon dioxide, triethanolamine and camphor for aroma.
Biofreeze's other inactive ingredients are FD&C blue No.1, FD&C yellow No.5 and extract from Ilex paraguariensis. FD&C blue No.1 is an artificial, water-soluble blue dye approved by the FDA for food, drug and cosmetic uses, notes Drugs.com. FD&C yellow No.5, called tartrazine, is an FDA-approved and commonly used food, drug and cosmetics dye. Tartrazine is in the azo class and is known to cause asthma and other allergic reactions, states the National Center for Biotechnology Information. Ilex paraguariensis is a shrub commonly known as Paraguay tea, states the U.S. Department of Agriculture.