I'd be wary of the stuff you get in pharmacies. It can have acetilnide added, which is a toxin. The higher potencies. 10%, 15% etc, tend to be purer.

You can get 35%, and dilute it 10x.

I go to a chemical nutrient supply store to get them.

I guess there will be a street full on them in your town.

You can also rub it on your skin, if the dilution is low enough.