What are the side effects of icy hot for arthritis therapy ?

Local irritation: There are very few long term effects and not much gets absorbed into the body, however some people can be allergic to the compounds and develop a rash or inflammation where this is applied. These will typically resolve if the therapy is stopped.

None: Icy hot is just a topical cream. It has no lasting effects or serious side effects if used as directed. Check the warning label for appropriate use.