It’s widely available.
https://www.puritan.com/dhea-522?scid=45174&cmp=msn-_-Bing_NB_Supplements&scid=45174&tf_adid&tf_asid=1265538642932293&tf_cid=402398527&gclsrc=ds
No, it’s not.
The form you point to is the wrong substance, called “Dehydroepiandrosterone.”
I mentioned all of this in my first comment.