In fact, the easiest way is to try to buy products in the flagship store. The products bought in the flagship store are basically genuine, and there will be no fakes. At present, John Jeff has no official way to verify the authenticity of the product. Try to buy in official stores or flagship stores.
In addition, don't blindly look for John Jeff's certification online. The certifications issued by many posts are mostly different versions of John Jeff's products, which cannot be used as a good basis for certification. If you want to know if the cosmetics you bought are fake, you can take them to the National Cosmetics Quality Inspection Center for inspection. If it is fake and shoddy products, consumers can complain.
Many fake merchants sell a lot of products of some good brands under the slogan of year-end clearance, and the price may be much cheaper than that on the market. The more so, be rational and don't be deceived. It is very likely that what you bought in your hand is only a few dollars of inferior raw materials, which is a far cry from the real thing.