What ingredients are in the patch?
While the particular ingredients are a company trade secret*, the patches are made to stringent GMP standards. There is however the crustacean derivative ‘carapace powder’ as one of the ingredients, so if you’re allergic to shellfish or seafood then the patches shouldn’t be used.
Please be aware that labelling laws don’t require a medical device to list ingredients aside from ingredients that can interact with other medicines or that may be regarded as a known allergen.