Assessing reviews and testimonials: what a review can prove and what it cannot

A customer review can say reliably whether an order arrived, when, in what condition, and how the shop responded when something went wrong. About the identity, purity or content of a research material it can say almost nothing, because the writer had no way of measuring them. That distinction — the experience of the transaction on one side, the quality of the material on the other — is half of assessing a review. The other half is judging whether the review is genuine at all.

European and Greek law now treat fake reviews as an unfair commercial practice and require shops to say whether and how they check that reviews come from real buyers. That helps, but it does not solve the underlying problem: a perfectly genuine review is still not evidence of what is in a vial.

Why testimonials are not evidence

A testimonial is one person's account of something that happened to them. Even when it is sincere, it has three limits that no number of testimonials overcomes. There is no comparison: the writer does not know what would have happened with different material or without it. There is no measurement: what it describes is perception, not data. And there is selection: people write mainly when they have something unusual to say, and a shop displays mainly what flatters it. The same mechanism makes a study without a control group unreliable; the four checks that decide whether a study deserves trust all fail when applied to a testimonial.

With research materials there is an additional problem. A testimonial describing what someone felt after using a material supplied only for laboratory research is not merely unreliable as data; it describes a use that the product itself excludes. A shop that publishes such testimonials, or leaves them standing on its pages, is making through its customers the claim it could not make directly.

Verified versus unverified reviews

A "verified purchase" label means only what it says: that the account which wrote the review completed an order. It does not mean the review is objective, that the writer received nothing in return, or that the shop publishes every review it receives. The international standard ISO 20488:2018 on online consumer reviews sets out what a reliable process requires: a written code of practice, transparency about how reviews are collected and moderated, and measures to limit biased or fraudulent reviews ^[5].

Since 2022 this has been more than good practice. Directive (EU) 2019/2161 added an express provision to the Unfair Commercial Practices Directive: where a trader provides access to consumer reviews, information about whether and how it ensures that published reviews originate from consumers who actually used or purchased the product is regarded as material ^[1][2]. Leaving it out is a misleading omission. In practice, a shop with reviews should explain somewhere how it checks them. If it does not, you already have an answer.

Signs of fabricated reviews

No single sign proves that a review is fake. But the more of them occur together, the less weight the whole set deserves:

• Ratings almost exclusively at five stars, with no middling or negative review at all.
• Many reviews within a few days, often just after the shop opened or a product launched.
• Generic text that would fit any product — "excellent quality, will buy again" — with no detail about delivery, packaging or contact.
• The same phrases, the same spelling mistakes or the same structure across reviews from different "customers".
• Reviews describing effects on the body for material sold for research only.
• Claims of "lab-confirmed" purity from customers who do not say which laboratory or which report.
• No response from the shop to complaints, or, conversely, identical responses to all of them.
• Reviews that appear only on the shop's own website and nowhere else.

The reverse holds too: a few negative reviews to which the shop replies specifically are often more reassuring than a hundred perfect ones. They show that reviews are not filtered and that someone deals with problems.

The legal framework for false reviews

Directive (EU) 2019/2161, known as the "Omnibus" Directive, has applied since 28 May 2022 and added two items on reviews to the list of practices considered unfair in all circumstances ^[2]. The first prohibits a trader from stating that reviews of a product are submitted by consumers who have actually used or purchased it without taking reasonable and proportionate steps to check this. The second prohibits submitting, or commissioning another person to submit, false consumer reviews or endorsements, and misrepresenting consumer reviews or social endorsements, in order to promote products ^[1][2]. As the European Commission summarised it, selling, buying and submitting false consumer reviews is now expressly prohibited ^[4].

In Greece, the Directive was transposed by Law 4933/2022, which amended Law 2251/1994 on consumer protection — among other things Article 9e on misleading omissions, so that it covers information on how reviews are checked ^[3]. Enforcement lies with the General Secretariat of Commerce, which accepts complaints through an online platform and the 1520 consumer line ^[6], while the Hellenic Consumer Ombudsman, an independent authority, mediates in the out-of-court resolution of disputes between consumers and businesses ^[7].

The problem is not theoretical. In an EU-wide website check coordinated by the Commission, consumer authorities in 26 member states, Iceland and Norway examined 223 major websites: on 144 they could not confirm that the trader was doing enough to ensure reviews were authentic, 118 gave no information about how fake reviews are prevented, and at least 55% were found to potentially breach the Unfair Commercial Practices Directive ^[4]. The check covered large online shops, marketplaces and booking sites, not the research-materials trade specifically; for that trade no published measurement exists.

What information a review actually gives

Take away what a review cannot know, and something useful remains. A buyer who describes when the parcel arrived, whether the coolant was still cold, whether the batch number on the label matched the certificate, and how the shop responded to a mistake is describing things they saw and could judge. That is the information worth looking for.

A special case is the review that cites its own analysis. If it names a laboratory and a report number, it can be checked like any other report. If it does not, it is a third party's claim about something you cannot see.

Where to look for real documentation

For the quality of the material, the documentation is not in the reviews but in the batch documents: a certificate of analysis with a named laboratory and report number, the batch number matching the label, and confirmation of the report by the laboratory itself. Where the outcome of an experiment depends on the identity and purity of the material, the only conclusive evidence is independent analysis of a sample — and how you tell whether a peptide is real is explained precisely as a succession of such layers of documentation.

Reviews have their place in the decision: they tell you whether a shop delivers, how it packs and how it behaves when something goes wrong. Read them for that, and only for that.