I tried the crystal and it worked for a while, had to go back to the other for a while then tried the crystal again. I told my sister inlaw about it and she said no one would sit near her so she went back to the other stuff. I think the crystal depends on the body's ability to use it. I found that I had a cyst after many years of using the store bought stuff and it went on till my doctor said get off the stuff and find something else. I decided since the crystal is only good for so long that I should try using the other stuff on only half of the arm pit and it works for me. Not sure about aluminum but I should start checking too. I alternate the top part of the arm pit for a while and then the lower part for a while. The cyst is gone and never came back so it must be working without totally blocking the ability to sweat some. I wish they would not put stuff like aluminum in our products.