Malachi Love-Robinson, 18, was arrested after examining and providing medical advice to an undercover police officer.
He was released on bail on Wednesday.
Mr Love-Robinson has denied that he posed as a medical doctor and said he only used the title because he had obtained a PhD online.
"This was me simply trying to do something for the community in a light that I saw that was needed," he told WPTV, a West Palm Beach news channel.
"Honestly, if you ask me many people are getting tired of hearing that they have to take a script just to feel better."
The website of the New Birth New Life Medical Center describes him as a "well rounded professional".
In January 2015, at the age of 17, he was reportedly caught walking around a local hospital wearing a white coat and carrying a stethoscope.
He has been charged with practising without a medical licence, and theft, after allegedly stealing and forging three cheques from an elderly woman who sought treatment for stomach pain.
In a brief media conference on Wednesday evening, he said he was "deeply saddened and a little disrespected" by the accusations and asked for privacy.
Mr Love-Robinson has since insisted in media interviews that he has certifications to practise alternative medicine, including naturopathy.
Scans of certificates from the American Alternative Medical Association and American Association of Drugless Practitioners had previously been posted to his Facebook page, which now appears to have been taken down.
But the state of Florida no longer offers naturopathy licenses and only licensed doctors are allowed to offer such services in the state.
Mr Love-Robinson said he became interested in alternative medicine while suffering from illnesses during childhood.
According to the Palm Beach Post, he claims to suffer from the auto-immune disease lupus, while a post on his Facebook page earlier this month said he was suffering from kidney cancer.
The Palm Beach County sheriff's office says Mr Love-Robinson examined an 86-year-old in December who suffered from severe stomach pain.
He allegedly diagnosed her with arthritis and sold her vitamins, receiving more than $3,000 (Â£2,090) for a series of home visits.
During one visit, she told police, he called an ambulance to take her to hospital and is alleged to have stolen and forged cheques worth nearly $2,800 after she left her purse and house keys with him.
A teenager charged with operating a fake medical practice in the US state of Florida has said he was just trying to help people through alternative medicine.