I wouldn't risk a 4 oz on carry on, they go by the label. 3.4 Oz is the limit
a smaller one should be fine, they don't care what it is. otherwise check it in for the larger bottles?
The do say medications are exempt, but they would be arguing there is no prescript
ion label etc.
TSA confiscated my small ice/heat packs once (medically necessary for my TMJ).
/www.tsa.gov/travel/security-screening/liquids-rule