Most customers do not have side effects with S’moo, however everybody reacts differently to it based on your body, so there isn't really a crystal clear answer to that. We always recommend checking in with your doctor to be sure that S'moo is right for you prior to adding S'moo into your routine! You can also read the reviews here to see what other people have said or join our community to ask others’ experiences! If you have any other questions, please feel free to email us at hi@thesmooco.com.