Navigating the legal landscape of weight loss supplements

By Danielle Masterson

- Last updated on GMT

Getty Images / altmodern
Getty Images / altmodern

Related tags Weight loss Weight management Obesity Fda Warning letter

Over 42% of adults in the US are considered obese—giving weight loss brands easy marketing fodder amid the obesity epidemic. Unfortunately, this category of supplements has a checkered history, and has become labeled as one of FDA's problem children.

According to the FDA​, “Hidden ingredients are increasingly becoming a problem in products promoted for weight loss,​” prompting the agency to keep a close eye on the category. 

“This is a red flag category for regulators at all levels – FDA, FTC, State Attorney Generals – as well as the class action bar,” ​cautioned Attorney Marc Ullman of counsel at Rivkin Radler LLP. “The category is directed at what FDA and FTC consider a vulnerable population and historically has been rife with products making exaggerated if not fraudulent claims.”  

FDA has been scrutinizing over-the-counter products, frequently represented as dietary supplements, which contain hidden active ingredients. Consumers may unknowingly take products laced with varying quantities of approved prescription drug ingredients, controlled substances, and untested and unstudied pharmaceutically active ingredients,” ​explained Attorney Pooja Nair, partner at Ervin Cohen & Jessup LLP. “In June and July 2021, FDA released public notifications through its medication health fraud website section advising consumers not to purchase certain products promoted and sold for weight loss due to these hidden ingredients.​”

Amazon also got an advisory letter from FDA, detailing violative products that the Agency bought on Amazon's website.  That prompted the ecommerce giant to update its specifications for dietary supplements with a new set of requirements​ for sellers of weight management and also made changes to COA stipulations.

In November, Amazon began requiring products in the weight loss category to provide test results that prove that they are free from the adulterants Sibutramine, Desmethylsibutramine, Phenolphthalein and Fluoxetine.

The challenges 

Ullman said substantiation is always a challenge in this category.  “Both the FDA and FTC are extremely skeptical of products in this category and neither believe that there can be a magic bullet for weight loss and that the absence of reference to diet and exercise is a red flag.  Finding an effective product that can work without stimulants or significant side effects remains an ongoing struggle.”

However, Nair pointed out that FDA's guidance on what “substantiation” actually means is lacking. “FDA has acknowledged ‘there is no re-established formula as to how many or what type of studies are needed to substantiate a claim,’ but stated that it recommends companies consider four factors. Those factors are: (1) the meaning of the claims being made; (2) the relationship of the evidence to the claim; (3) the quality of the evidence; and (4) the totality of the evidence. Note that weight loss claims do not require premarket review or approval.”


Randomized, double blind, placebo controlled clinical trials for weight loss supplements are considered the gold standard for substantiating clinical evidence. 

Ivan Wasserman, managing partner of Amin Talati Wasserman LLP, said the biggest challenge, like in other categories, is matching the claims to the clinical evidence. “Were the subjects in the study on a calorie restricted diet?    Were they only one gender?  Were they all obese at the start?  Did they lose a significant amount of fat but not weight (or vice-versa)? Was the amount of weight lost clinically significant?  An unqualified claim that just says ‘Take our Supplement And Lose Weight!’ could be challenged as being deceptive depending on the answers to these and other questions." 

Marketing dos and don'ts

Ullman said including a reference to diet and exercise as well as slow, steady weight loss is always advisable. 

“Beware of misleading percentage claims.  If a supplement claims ‘Lose 100% (or 2X) more weight than dieting on your own,’ and a study showed after 6 months subjects in the supplement group lost 2 pounds, and subjects in the placebo group lost 1 pound, while the claim may be literally true, it is easy to see how it might be misleading,” ​warned Wasserman. “ Also while it may be possible to rely on studies conducted outside the USA, careful consideration should be given to ensure that differences in genetics or diets do not cause the results not to be reliable support for the effects of the supplement in the American population.”

Testimonials under scrutiny

“Weight loss marketing of course often relies on testimonials and before and after images, and the days of ads featuring people talking about losing a lot of weight  and showing dramatic transformations with just a ‘Results Not Typical’ disclaimer are long over.   Now if the results shown are not ‘typical,’ the typical results must be disclosed, which requires clinical evidence to support,”​ said Wasserman. 


Nair pointed out that the FTC recently issued a Notice of Penalty Offenses Concerning Endorsements, which outlined its prohibition on companies using testimonials to make or imply unsubstantiated or otherwise deceptive performance claims and misrepresent that the experience described by the endorser of a product represents the “typical or ordinary experience of users.” 

“This will directly impact weight loss products that advertise through user testimonials. The FTC has indicated that it will directly investigate companies for these types of violations, and has been ramping up investigations and expanding its power to issue fines,”​ she added. 

Lights, camera, FDA action 

Wasserman said choose words carefully to avoid unwanted attention from the FDA: Before you hear the word ‘Action’ and the sound of the clap from the clapboard (which I love), be sure that all of your advertising scripts have been thoroughly reviewed for compliance with all regulatory requirements."

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