Can phosphatidylserine cause headaches ?

Not likely: Phosphatidylserine is possibly safe for most people. It’s been used in research studies for up to six months. I phosphatidylserine use can, however, cause side effects including insomnia and stomach upset, particularly at doses over 300 mg. Products made from animal sources could transmit diseases, such as mad cow disease. To date, there aren't any known cases of human (ref: webmd).