No, because the screws contain more than 90 % magnesium, corresponding to around 150 mg in a MAGNEZIX^® CS 3.2 (20 mm length). This amount is roughly comparable to the amount of magnesium contained in three large bottles of mineral water, and can be ignored when compared to the total amount of magnesium in the human body, especially because the screws degrade over a longer period of time. More about Magnezix you can read here