Just because there is regulations does not mean that there were not people calling themselves Doctors and selling snake oil. Ridiculous. Read this entry:
https://en.wikipedia.org/wiki/Quackery#History_in_Europe_and_the_United_StatesParticularly this:
"The number of internationally marketed quack medicines increased in the later 18th century; the majority of them originated in Britain[14] and were exported throughout the British Empire. By 1830, British parliamentary records list over 1,300 different "proprietary medicines,"[15] the majority of which were "quack" cures by modern standards."
And this:
"Similar advertising claims[25] to those of Radam can be found throughout the 18th, 19th, 20th and 21st centuries. "Dr." Sibley, an English patent medicine seller of the late 18th and early 19th centuries, even went so far as to claim that his Reanimating Solar Tincture would, as the name implies, "restore life in the event of sudden death". Another English quack, "Dr. Solomon" claimed that his Cordial Balm of Gilead cured almost anything, but was particularly effective against all venereal complaints, from gonorrhoea to onanism."
So....yeah...there were people who claimed to be doctors - even after regulations were introduced. Don't be obtuse.