Magnesium Chloride. I buy a pharmaceutical grade magnesium Chloride from Amazon. Just under 18 bucks for two pounds and will probably make a 100 bucks of magnesium oil compared to buying the oil directly on line. I make sure that heavy metals are removed from the the magnesium chloride. Heavy metals are not something you need to absorb. As a aside, the bath type of magnesium chloride has heavy metals and I do not recommend using them as a bath oil or magnesium oil spray.
How to use magnesium oil spray. I use a sprayer that is available from on line. It comes with a nice cobalt blue bottle. The nice thing is that each of the squirts with the sprayer is about 18 mg, so you know how much you are using. Spray at least three times a day. Spray problem areas five times and rub it in and sore muscles will disappear with in a half hour or be greatly diminished. If it did not do much it is because you are very low in magnesium. The next time it will work better and relief will last longer. I squirt my skin at least twenty times a day. But if I was to do sixty times a day it would not overdose me. Overdose is impossible except in the very rare instance of kidney failure or compromise. So if you are thinking you may need kidney dialysis in the future because your kidneys are failing, don't use this.
You may notice that the spray solution causes "tingling". If this is a problem dilute the magnesium oil with more distilled water. Don't use tap water. The oil may also feel uncomfortable on the skin. Tingling tends to deminish with use. After a half hour you can remove the magnesium oil with a wet wash cloth.
I also notice if I put the oil on my chest I get a slight rash, so I don't do that. The skin tends to me more tolerant on the legs, feet, back and abdomen. Don't for get, if you have sore muscles apply locally in larger amounts as above.
Lastly, if you don't sleep well dose up before going to bed. You will sleep better. Do it a half hour before bedtime and you can get about all the benefits even if you wash it off just before going to bed!
Just remember, every time you have a alcoholic drink, every time you have added sugar, every time you eat some thing with refined grains you lose magnesium. And when you eat vegetables that have been grown for decades in a commercial growing area there is little magnesium in the soil. It is not easy to get a normalized magnesium level and maintain it in our society.
Diseases of Civilization are everywhere in just about everyone.