Icy Hot
From Chempedia
How Icy Hot Works
Icy Hot is one of numerous ache, muscle, and joint relief medicines. One of the other types is Ben Gay. Each of these medications are applied on the skin and rubbed in until it is fully absorbed by the skin. These medications relieve pain by causing a cool feeling on the applied area shortly followed by a warming sensation. Two main molecules called Methyl Salicylate and Menthol cause these feelings. Each creates a different sensation. The remainder of the essay will explain how each compound works, what it does, and an explanation of how Icy Hot works.
The first molecule is Menthol, as seen at right.
The chemical formula for Menthol is C10H20O. Menthol falls into the category as an alcohol, which is an organic compound that contains a COH functional group (Silberberg, 628). It can either be obtained via natural or synthetic sources. Menthol is responsible for the cool feeling one feels when the Icy Hot is first placed on the skin. Studies performed by Dr. David Julius show that Menthol stimulates the temperature receptor known as CMR1 creating the feeling of cold. It is speculated by Dr. Julius that the similarity between receptor CMR1 and the hot receptor VR1 are the primary ways that a person feels hot and cold. (Brockenbrough, paragraphs 4 – 5)
While it is not a certainty, many believe Icy Hot relieves pain by stimulating the temperature receptors, sending impulses to the brain via nerves. The nerve impulses from the hot/cold sensations synapse with the pain receiving nerves preventing pain from reaching the brain. Icy Hot does not numb the affected region, but it is believed to override the pain stimulating the nerves with sensations of hot and cold. This is how it is believed Icy Hot reduces pain and creates the different sensations of hot and cold.
The next major molecule, Methyl Salicylate, C6H4(OH)COOCH3, composes approximately 30% of Icy Hot. This organic compound is obtained by maceration and subsequent steam distillation from leaves and bark but it is also produced synthetically. (Geneva) This compound creates the warming sensation and the wintergreen scent. This occurs when the Methyl Salicylate is absorbed into the skin. It then dilates the capillaries closest to the skin increasing blood flow to warm the region.
It is due to the dilation of the capillaries that it may be dangerous to use while taking blood thinners and anti-coagulants. Methyl Salicylate is highly toxic if consumed, though it is absorbed slowly through the digestive system and can be flushed out if caught quickly enough. If it is not removed from the system, it causes severe tremors, possible seizures and even death.
Icy Hot is a liniment. Liniments all reduce aches and minor pains. Icy Hot uses Methyl Salicylate and Menthol to create the warm and cold feelings that reduce pain by synapsing with nerves to send warm and cold sensations to the brain instead of pain. However, the exact chemical reaction that makes this occur still eludes scientists.
Bibliography
Brockenbrough, Martha. "Martha Talks Back: User Questions Answered." Encarta. Encarta. 26 Sept. 2005 http://encarta.msn.com/encnet/features/columns/?article=questionmint.
Kirk-Othmer Encyclopedia of Chemical Technology. 1997 John Wiley & Sons Inc. Dec. 4 2000. 11 Nov. 2005 http://www.mrw.interscience.wiley.com.floyd.lib.umn.edu/kirk/articles/salithom.aol/sect7-fs.html
"Menthol and Peppermint." Vinayak Corporation. 29 Sept. 2005 http://images.google.com/imgres?imgurl=http://www.vinayakcorporation.com/images/formula.gif&imgrefurl=http://www.vinayakcorporation.com/menthol.htm&h=240&w=160&sz=7&tbnid=FpTu_4-uT3YJ:&tbnh=104&tbnw=69&hl=en&start=6&prev=/images%3Fq%3Dmenthol%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DG
"Methyl Salicylate.." chemistry.org. 26 Sept. 2005 http://www.chemistry.org/portal/a/c/s/1/acsdisplay.html?DOC=HomeMolecule%5Carchive%5Cmotw_methylsalicylate_arch.html
"Toxicological Evaluation of Some Flavouring Substances and Non-Nutritive Sweetening Agents." FAO Nutrition Meetings. 26 Sept. 2005 http://www.inchem.org/documents/jecfa/jecmono/v44aje28.htm
"Methyl Salicylate, Menthol." IPCS inCHEM. Aug. 1967. Geneva. 07 Nov. 2005 http://www.inchem.org/.
Silberberg, Martin S. 3rdrd ed. New York: McGraw Hill, 2003. 628-629.
Researched by: Andrew Kurpiewski, Lindsey Leibel, Alex Hintz, Nichole Eck
