We source NMN from UTHEVER, and we assure the top quality in the industry. It is also certified by Intertek, the world's largest testing and certification body. Human clinical trials conducted with NMM Uthever showed that it has the best absorption efficiency. It also has a high purity of 99% or more. We have also received certification for high-purity raw materials from inspection agencies. We also go through heavy metal testing, which allows us to verify there are no heavy metals in any of the ingredients and that they are safe for consumption.