As a cosmetic product, Pen Nail Polish must adhere to strict safety regulations. You must require an MSDS (Material Safety Data Sheet) and a COA (Certificate of Analysis) from the supplier. For the US market, ensure ingredients are FDA-compliant; for the EU, the product must meet EC No. 1223/2009 regulations and be registered on the CPNP (Cosmetic Products Notification Portal). Additionally, verify that the product is '10-Free' or '12-Free', meaning it is devoid of harmful chemicals like formaldehyde, toluene, and DBP.