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Clinically proven: Research reveals the power phrase reshaping consumer purchasing – spotlight

Guest spotlight: Inside the Bottle partner Radicle Science reports on new research revealing key information on-package that helps support consumer trust in supplements

August 29, 2023

7 Min Read

The dietary supplement industry faces a growing consumer trust problem. Product claims are often met with skepticism, likely fueled by mainstream media allegations of lack of regulatory oversight and absence of scientific proof. Moreover, for the first time in nearly a quarter century, FTC is also tightening regulations and enforcement around claims, releasing the new landmark Health Product Compliance Guidance in December 2022, investigating social media companies for allowing paid advertising of misleading health products, and cracking down on companies using unproven health claims. In April 2023, nearly 700 FTC warning letters were sent to some of the world’s leading health and wellness brands, putting them on notice "that they should avoid deceiving consumers with advertisements that make product claims that cannot be backed up or substantiated."


Unsurprisingly, those in the supplement industry are increasingly interested in using clinical trials on finished product formulas to validate claims and bolster consumer confidence. To have a product that is "clinically proven" (i.e., found to perform significantly better than placebo in high quality human clinical trials compliant with FTC and FDA regulations) is among the highest forms of validation—effectively safe-guarding companies from reproach by the media, litigators and regulators, while also enabling them to rise above competitors and gain the trust of consumers. 

A recent consumer psychology study conducted by the University of California San Diego (UCSD) in collaboration with Radicle Science sheds light on the consumer perception of "clinically proven" claims and the value of clinical research and strong claims in consumer purchasing behavior of supplements.

Radicle Science, an Inside the Bottle partner, is a healthtech B-Corp, offering dietary supplements an easy path to prove their true effects beyond placebo, across diverse conditions and populations. Launched in 2021, Radicle Science combines gold-standard double-blind randomized placebo-controlled scientific design, with a unique AI-driven, virtual, direct-to-consumer approach, to deliver standardized and automated “Proof-as-a-Service” clinical trials at unprecedented affordability, speed and scale. The purpose of Radicle’s collaboration with UCSD was to further explore factors affecting consumer purchase decisions for dietary supplements. The hypothesis going into the study was that strong effectiveness claims would increase consumer intent to purchase and/or pay a premium. 

The UCSD Study


A large sample (N=1,231) of consumers were recruited online to participate in the study. There were roughly equal numbers of men and women, and the sample was well-distributed across age groups from 18 to 65 and over. 

The findings:

  • "Clinically proven" significantly increases consumers’ intent to purchase.

Each subject was randomized to see an image of a supplement bottle, and asked to report their likelihood of purchasing the product (0-10, on sliding scale, with ‘0’ being "Not likely at all" and ‘10’ being "Very likely"), assuming they were feeling stressed.  All the bottles shown were identical in appearance and carried the claim “reduces stress,” except some carried an additional “clinically proven” claim on the label. 

Based on their responses, participants were categorized as “Not likely to purchase” (score of 0 to 6), “Neutral” (score of 7 to 8) and “Likely to purchase” (score of 9 to 10). The odds of being “Likely to purchase,” relative to being “Not likely to purchase,” were then compared across product groups.

Those who saw the bottles carrying the additional “clinically proven” claim had approximately two-fold greater odds of being “Likely to purchase,” relative to those who saw the bottles that only carried the “reduces stress” claim. This difference was statistically significant.[1]

  • "Clinically proven" significantly increases the amount consumers are willing to pay for a product

Each respondent was once again shown the product to which they were randomized, and asked to provide the amount of money they were willing to spend ($0-$100, on a sliding scale), assuming they were feeling stressed.

The addition of the “clinically proven” claim on a product label significantly increased the amount respondents were willing to spend.[2] Those who saw the labels containing the “clinically proven” claim were willing to spend approximately $5 more for their product, on average, relative to those who saw the labels that only carried the “reduces stress” claim—this was at least a 20% increase in the price they were willing to pay compared to those who were shown the base label without the “clinically proven” claim.

  • "Clinically proven," "Tested for contaminants," and "Good user reviews" were the top factors that influence intent to purchase.

Respondents ranked 7 factors in descending order in terms of their importance when purchasing a product (1 being most important). Based on the frequency of appearing in the top 3 rankings, the most influential factors were identified:

  • “The product has been proven effective in clinical trials” emerged as the most important factor; 76% of respondents ranked this as a top 3 factor

  • “The product has been tested to be free of contaminants” was the second most important factor; 52% of respondents ranked this as a top 3 factor

  • “The product has good user reviews” was the third most important factor; 50% of respondents ranked this as a top 3 factor

  • “Whether the product uses ingredients I recognize” was the fourth most important factor; 43% of respondents ranked this as a top 3 factor

  • “Whether the product has been recommended by someone I trust” was the fifth most important factor;  37% of respondents ranked this as a top 3 factor

  • “Whether the product taste/smell is acceptable” was the sixth most important factor; 27% of respondents ranked this as a top 3 factor

  • “Whether the product is organic” is the seventh most important; 15% of respondents ranked this as a top 3 factor


This study sheds light on the importance of strong claims in consumers’ purchasing behavior of supplements.  To our knowledge, it is the first study to assess how the incremental addition of a strong health claim on a supplement label could impact consumers’ likelihood of purchasing and willingness to pay. 


Participants were more likely to purchase—and pay far more for—products with labels that contained the phrase "clinically proven."  Specifically, consumers who viewed the label containing “clinically proven” were about twice as likely to have high purchase intent, and willing to pay at least 20% more, compared to those who saw the label without that additional claim.  Moreover, respondents most frequently ranked “proven effective in clinical trials” as a top factor when purchasing a supplement.  These findings highlight the consumer-driven need for high-quality clinical trials on supplement products that meet FTC and FDA requirements to substantiate strong structure/function claims.

While insightful, the study is not without its limitations. Namely,  it relies on self-reported data on potential behaviors among consumers, not on their actions in the real world. Data on actual purchasing behavior would more accurately reflect consumer priorities and the impact of substantiated claims on purchasing behavior.

Nevertheless, the study provides compelling evidence supporting the significant return on investment a “clinically proven” claim could garner due to consumers’ greater willingness to pay as well as higher intent to purchase.  It also highlights the importance of monitoring and anticipating evolving requirements from retailers and regulators as to the appropriate substantiation required in order to make strong label claims. 

While the shifting dietary supplement consumer sentiment and evolving regulations pertaining to claims may be viewed by some as headwinds, when coupled with actual independent consumer preference data, these trends are not only good for consumers to find products that work better than placebo, they also appear to be good for the bottom line for companies who undergo rigorous clinical trials and can prove (and make claims about) their effectiveness. 


[1] Based on  a multivariate logistic regression model adjusting for sex, age, race and ethnicity. The analysis excluded those classified as ‘Neutral’ (n=382).

[2] Based on Tukey pairwise-comparison tests, which adjust for the family-wise error rate.

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