With magnesium, my understanding is that the actual rate of absorption varies enormously between types. Further, any oral form significantly reduces absorption to about 20%. So 1000 mg of a good chelated form is internalised as 200 mg. I have seen an Epsom salts bath three times weekly proposed as a cheaper and better alternative due to it being absorbed through the skin. Another alternative is liquid magnesium but in that case dosage is not controlled.

All medications come with a risk of side effects, so why take them if you don’t have to? According to the U.S. Centers for Disease Control and Prevention, about seven out of 10 U.S. adults with high blood pressure use medications to treat their condition. But what many people don’t realize is that you can help control your blood pressure naturally by changing a few daily habits.
Sleep. Short and poor-quality sleep are both associated with raised blood pressure (40). On the other side of the spectrum, excessively long sleep may also be harmful. One study found increased blood pressure in those who got fewer than five hours of sleep per night and in those who averaged more than nine hours of sleep per night, when compared with people who slept around seven hours (41). I suspect that it’s not the long sleep itself that is the problem, but that some underlying condition is both increasing sleep requirement and raising blood pressure.