For me, magnesium gives only some temporary relief and doesn't address the cause of RLS.
I get long lasting relief with iron.
Low iron can result in low oxygen carried by the blood and nerve damage.
Magnesium and iron both effect/benefit the blood.
The reason magnesium can give some temporary relief is that when magnesium is taken, the blood vessels dilate. This results in a very relaxing effect in people who have enough blood to fill the now larger blood vessels (for people with adrenal fatigue magnesium can often make them dizzy or faint, due to low blood levels.)
This dilating of the blood vessels allow for more blood flow with increasing oxygen delivery - this is how magnesium can give temporary benefit to people who actually need more iron.
Iron and B12 are very important for blood and nerves health, they have really helped my family's health.