Mercari advertises items purchased on their site are authentic brands; however, they do not provide that authentication. It is up to the buyer to 'do the work' prior to purchasing. Be aware of sellers with zero items sold as they are often dupe products! Mercari doesn't monitor their site, you will often see multiple listings with the same picture for an array of prices. I fell prey to a scam seller to which Mercari refused to provide any assistance unless I (the buyer) pay to have the product authenticated and provide with them with proof the product is fake at which time I'd be provided with a credit it my account for future use.