The Ancient Minerals Magnesium Oil is the most potent of the products. If it is too strong on the skin, you can dilute the oil half spring water with half magnesium oil. There is also magnesium oil with MSM for enhanced absorption. The magnesium oil with MSM in it is called Magnesium oil ultra. In many cases once your body adjusts you can use the full strength product.
Both are available at LL's Magnetic Clay Co. http://www.magneticclay.com/
Dilute it. Start at 3:1 ratio mag to water. Go 50/50 if needed.