If a serum smells bad it usually means it works., This glutathione serum smells like rotten eggs and thats your first clue its highly concentrated. Glutathione is known for targeting Understanding Glutathione Smell in Skin Products Glutathione & NMN Ampoule. Volume: 30 ml. The jar is quite heavy and made of glass. The serum has a clear, gel like consistency. But its scent reminds me of rotten eggs , but that's exactly Numbuzin Glutathione Ampoule: Smells Bad But Works!