Mestinon is as cholinesterase inhibitor much like one of the ingredients in Parasym Plus, so I wouldn’t take them both at the same time. If you are like many of us and have fatigue/brain fog, you may be responding to Mestinon because it is boosting acetylcholine in your gut HOWEVER it won’t increase acetylcholine in your brain (for fatigue/brain fog). Parasym Plus will do both. Most of us can go off of Mestinon and take Parasym Plus instead and retain the GI effects but GAIN the brain effects. Be sure to check with your doctor. 😉