Yes, we have a person on my magnesium thread who made her own too.

The only downside is dosing. Making sure you get the right amount/ area applied.

I made some magnesium ointment once, using Aquaphor as a base. It seemed to work nicely, but I had a rebound effect the next day with MORE pain than I started with. This doesn't happen with oral or soaking.
I used the ointment on my right knee, and this was years ago.

So I never really pursued topical for myself after that or for others. I'll try the CVS product. It is only $10... which is not that much really. (if I can find it that is).

One thing to keep in mind is that epsom salts already have water added to the weight. If you look on the label it shows that.
So the amount of magnesium is less than you think by weight.

My hubby gets a stiff back where his shingles were. I'll try him first, and not use it every day...just in case there is a dosing issue.