If you think you are experiencing a Pycnogenol side effect, please let your healthcare provider know. Also, let your healthcare provider know if you develop something that "just does not seem right." While it may not be a side effect, your healthcare provider will be able to diagnose and treat the problem. Because little is known about the possible side effects of Pycnogenol, any information that individuals provide about possible side effects they experience can be valuable to the scientific community.