I purchased Penetrex from Amazon.
I jammed my wrist(metatcarpals) playing goalie in a soccer match Saturday. ( I had to sub for someone else and didn't get a chance to do my wrist warmups. )
Wrist was hurting at about a 4 on a 10 point scale.
I applied the cream, within 2 minutes my wrist felt normal with zero pain except at limit of wrist extension.
The effects lasted about 4 hours.