According to the European Commission’s Scientific Committee on Consumer Safety (SCCS) there is a need for more safety testing on copper nanomaterials used in cosmetic products. Concerns have been raised because of the potential for nanoparticles to be absorbed dermally or across a mucous membrane and enter cells.

SCCS analyzed 29 nano-sized copper products and found enough data to suggest possible systemic uptake of copper nanoparticles, which may lead to accumulation in certain organs, including the liver. There is a need for further investigation and evaluation on the subject as there is a concern that the use of colloidal copper on nano form can pose a health risk to the consumer. For more info, see here 

We have recently added five face masks containing copper and have that can be found along with multiple other products containing copper here