Are my headaches being caused by bovine collagen?

Yes, it is possible. One of the common side effects of taking bovine collagen is headaches. This can be down to a couple of things. Firstly, taking collagen might increase the amount of calcium in your body which leads to not only headaches but also nausea and fatigue. Secondly, if you're sensitive to the glutamic acid found in bovine collagen, taking it might trigger migraines and headaches. To ease this, take more water and avoid taking collagen right before going to bed.