Why a dietary supplement product page without reviews doesn't stand a chance. Not even with AI
Dietary supplements are bought on trust. Customers have no way to verify whether a capsule is easy to swallow or if it smells fishy; all they have is the experience of someone who has already used the product. And starting this year, the same applies to the AI assistant they consult instead of a search engine.
How many reviews a customer needs to see
The first five reviews increase the likelihood of purchase by 270% (Spiegel Research Center, Northwestern 2017). However, customers aren't satisfied with just five: 68% want to see 26 or more (PowerReviews 2021).
In the health and beauty category, conversions increase with review volume by up to 275.7%, and for food and drugstore items by up to 686.2% (PowerReviews 2021, 1.5M product pages).
And the number that hurts the most in this category: a rating of 4.0 to 4.7 stars sells the best (Spiegel 2017). A clean 5.0 rating from just three reviews looks suspicious.
A new reason to deal with it now
A growing number of people no longer type queries like 'which magnesium for night cramps' into a search engine, but into an AI assistant instead. A brand without a review profile is mentioned in its answers in just 1% of cases, while a brand with a profile of 1 to 13 reviews appears in 53.5% of cases (Seer Interactive 2026, 804,491 answers).
And Google Ads will only show star ratings in ads once you reach at least 100 reviews over 24 months.
Conversion growth by category
Review volume has the strongest impact on conversion rates in categories where trust and repeat purchases matter most.
PowerReviews 2021, 1.5M product pages
What about legislation?
The most common objection isn't 'it's not worth it', but 'we're not allowed to'. Yet, dietary supplements are the least regulated of all health categories.
Testing and reviewing is allowed
They must not write that it 'cured' their joints.
What to do right now
In supplements, capsule size, taste, and dosage come up repeatedly â the exact factors that determine whether someone buys a second package.
Recommendations
A single campaign produces more than just stars: it generates text for the product page written in the customer's language, social media photos, and reviews with retail partners.
At Testuj.to, we build campaigns in this category based on legal assessments and moderation; however, we do not promise a specific growth percentage in advance, as results vary from tens of percent to multiple folds depending on the initial state of the product page.
Sources: Spiegel Research Center, How Online Reviews Influence Sales (2017) · PowerReviews, The Ever-Growing Power of Reviews (2021) · Seer Interactive (2026) · Google Ads Help, Seller Ratings · Regulation (EC) No 1924/2006.
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