ABOUT ICY HOT
Icy Hot is arguably the most well known off-the-shelf topical application for muscle pain relief. Even Shaq is all about it. Icy Hot is produced and marketed by a Tennessee-based company named Chattum, a subsidiary of another company named Sanofi.
Their company’s brand portfolio boasts over twenty products, including notables like Allegra, Gold Bond, Rolaids, Aspercreme, and Selsun Blue.
ICY HOT ACTIVE INGREDIENTS
Also called wintergreen oil, this organic ester is naturally produced by many species of plants, particularly wintergreens. It is present in various levels in many of the Icy Hot products.
Wintergreen oil is also a salicylate, as evident by its proper name: methyl salicylate. Salicylates are compounds related to aspirin. By using them topically, it may help a patient avoid most of the negative side effects of taking aspirin or aspirin-related compounds by mouth, such as:
ulcers of the stomach and small intestine,
gastritis (inflammation of the stomach)
A randomized, double-blind, parallel-group, placebo-controlled, multicenter study published in 2010 concluded, "A single, 8-hour application of a patch containing methyl salicylate and l-menthol provided significant relief of pain associated with mild to moderate muscle strain in these adult patients compared with patients receiving a placebo patch."
Additionally, a study of collagen-induced arthritis in mice published in 2014 concluded, "[methyl salicylate] has great potential to be developed into a novel therapeutic agent for the treatment of RA."
However, in its pure form, methyl salicylate is toxic, especially when taken internally. People should never exceed the directions on the label due to the risk of salicylate toxicity (aspirin poisoning). A single teaspoon (5ml) of methyl salicylate contains 7g of salicylate, which is equivalent to more than twenty-three 300 mg aspirin tablets. It has proven fatal to small children in doses as small as 4ml.
Every rose has its thorn, right? To lighten things up (literally), when mixed with sugar and dried, methyl salicylate is triboluminescent. Which is almost as fun to say, as it is to see. It's an optical phenomenon in which light is generated through the breaking of chemical bonds in a material when they are pulled apart, ripped, scratched, crushed, or rubbed. Next time you've got some Wintergreen Life Savers and a dark room, try it out.
This organic compound is made synthetically or obtained from mint oils. It's present in various levels in all Icy Hot products.
Menthol stimulates the transient receptor potential channel melastatin 8 (TRPM8). This receptor is responsible for the well-known cooling sensation it provokes when inhaled, eaten, or applied to the skin.
It also has weak analgesic (pain-killing) effects due to its selective activation of our κ-opioid receptor. This protein mediates many effects including changing our perception of pain, consciousness, motor control, and mood.
Camphor is present in the following Icy Hot products: Advanced Pain Relief Cream and Arthritis Pain Relief Lotion.
This waxy solid has a strong aromatic odor. It is found in the wood of the evergreen tree Cinnamomum camphora; Dryobalanops aromatica; Ocotea usambarensis; and dried rosemary leaves (Rosmarinus officinalis). It's easily absorbed through skin and produces a cool-feeling like menthol.
ICY HOT SIDE EFFECTS
There are no known major side effects for using Icy Hot as advised (on the skin, external use only), although one should seek medical attention if a severe allergic reaction occurs. It's also not a good idea to use on broken or damaged skin, and be sure keep it clear of the eyes - ouch.
PRECAUTIONS & WARNINGS:
Methyl Salicylate (wintergreen oil) might cause an allergic reaction in people who are allergic to aspirin or other salicylate compounds, or have asthma or nasal polyps. Use wintergreen with caution if you have one of those conditions.
Wintergreen oil can be poisonous for children. Taking 4-10 mL of wintergreen oil by mouth can be deadly. So keep away from the kiddos and do not use wintergreen oil on the skin of children less than 2 years old.
If you are pregnant or breast-feeding, wintergreen is safe in amounts found in food, but there's inconclusive evidence to know if it's safe in the larger amounts internally or topically. Either clear usage by your doctor, or select a topical gel that does not include wintergreen oil (methyl salicylate) on the ingredients label.
ICY HOT SUMMARY
I found an established body of research that may suggest the use of menthol and wintergreen oil for mild pain relief. Given the very low risk and very limited side effects, it would seem worth a try for individuals seeking a complementary and/or off-the-shelf product for pain relief.