The website Clinicaltrials.gov is home to a broad spectrum of clinical trials, both legitimate and illegal. Information provided by FDAmaps.com showed how easy it is to register trials on the site and few questions are asked pertaining to the trials. Over the past 20 years, clinicaltrials.gov has become a hub for illegitimate clinical trials, under the security of a government-owned website.
Prescription products fall into the category of trials that require FDA approval but many supplements like those that manage weight loss, do not. Under the FDA's enforcement discretion, there are trials that operate illegally and others that charge patients for their involvement, that are allowed to do so because they are low-risk. Despite disclaimers alerting patients to the fact that some trials may not be FDA approved, it can be difficult to weed out phony opportunities.
The burden of understanding the difference currently falls on the patient but knowing the signs can help distinguish the legitimate from the dangerous. Not all listings on the site are credible and submitters from outside of the United States are more likely to be illegal. Any trial that charges patients for their participation is always illegal.