Anyone who is on Instagram, YouTube, Facebook or TikTok often comes across offers that sound tempting: from weight loss powder to lucrative investments. In our series, reporter Judith Henke takes a look at these products. What is behind it, how serious are you?


It’s finally summer. At least in my eyes this is the most beautiful time of the year. No more wool sweaters, no more biting wind blowing in your face while cycling. Only one thing bothers me: Somehow everyone around me turns brown. Only I remain so pale, as if I would like to apply for a fifth Twilight film.

That’s why an Instagram post by Gerda Lewis, the former participant in the casting show “Germany’s Next Topmodel” and then “Bachelorette” in the RTL show of the same name, caught my attention.

In the picture, she has her well-tanned back turned sideways to the camera, holding a spray can in her hand. “If you want to keep your tan for an extra long time, I can give you ‘forever

Lewis, who has around a million followers on Instagram, is just one of many influencers currently promoting self-tanning brand b.tan. The “Germany’s Next Topmodel” winner Celine Bethmann and the model Marie Dahmen also rave about the tan from the can.

Some even make little videos demonstrating how to use the self-tanner. So does Gerda Lewis. She shares a few tips to keep your tan from being patchy or short-lived. “Leave the product on for 6-8 hours for the strongest result,” for example.

Handy, especially for self-tanner newbies like me. Armed with such tips, I buy two different self-tanners from the brand and try them on only one leg to be on the safe side. Not that I’ll be totally orange later.

I decide to apply the self-tanner just before bed – that way it should be left to soak in for six hours. Not a good idea, because the next morning I notice that my bed sheet has also browned.

But at least my legs are tanned now, but I’m not satisfied. Because the tan has settled a little more in the skin pores than on the skin itself.

Luckily it got better over the next two days. But three days later my legs are more red than brown – and that’s so noticeable that I’m even asked about it in the outdoor pool.

I’m pissed off. Gerda Lewis promised me that I could “bring the summer home” with it. Does she even use the product herself? At least that’s what she emphasizes on Instagram.

But is “b.tan” really responsible for her even tan? Or is it because in six months she has vacationed in sunny countries more often than I have in the last four years?

Unfortunately, she does not answer my question. Even though I’m not the first to be disappointed with their product recommendation. Among her promotional posts, some of her followers are also criticizing “b.tan.”

“The color was absolutely not nice and it didn’t last,” writes an Instagram user. Another follower even describes the self-tanner as “horrible” and adds a tip to Lewis: “Stop such incredible advertising.” Lewis responds to a few of the critical comments, writing for example: “One must not forget that every person has a other skin types.”

Critical customer reviews are also piling up on the online shopping site of the drugstore chain “dm”, which sells the “b.tan” self-tanning lotion.

Just like me, some customers, especially with the “b.tan” product “Love at first tan”, experience that the tan settles in the pores.

Others complain of dry skin. One customer even writes: “After applying it, I unfortunately noticed that a rash had formed on my body. Normally, I’ve never had problems like this after using a self-tanner.”

Another review says: “Everything is itching for it.” And a buyer writes in complete shock: “I’m actually orange!”

Doesn’t exactly sound like a trustworthy product. But I’m all the more surprised how many reviewers are completely enthusiastic and give the self-tanner five stars.

The “Love at first tan” self-tanner has an overall rating of 4.5 out of five stars. Were the disappointed customers and I perhaps too strict? Or is it more because about 90 percent of the five or four star ratings were given by so-called product testers?

Product testers do not have to pay for the product – in this case the self-tanner. “Dm” sends it to them, and it’s their job to leave a review on the online site. When it comes to the “love at first tan” self-tanner, the product testers seem to be significantly happier than the paying customers.

Only 13 percent of the one to two star ratings come from product testers. If only product testers were to rate the “b.tan” tanning mousse, it would even receive 4.7 instead of 4.5 stars.

I am surprised that “dm” only sends customers free products for a few online reviews. What’s in it for the drugstore? I’m asking someone who should know: Martin Fassnacht.

He heads the Chair of Strategy and Marketing at WHU – Otto Beisheim School of Management. “Consumers have a need to feel validated in their purchasing decisions,” he explains. “Customer ratings play a very important role in this.”

If a potential buyer sees that other customers rate a product as good or very good on average, they feel strengthened in their decision to buy it.

“The credibility of positive customer reviews is higher than normal advertising.” The fact that the reviews come from product testers is often not even noticed by customers who have little time to think about it before making a purchase decision.

Accordingly, “dm” does not send its products to test customers out of sheer generosity. This is also the assessment of Christian Fichter, Professor of Business Psychology and Head of Research at the Kalaidos University of Applied Sciences in Zurich.

“Rating systems are very important in a customer’s purchasing decision,” he says. “So the temptation to trick the system is all the greater.”

The product testers, who were selected by “dm” by drawing lots, are usually grateful for receiving the product free of charge. That’s why they would also unconsciously write better reviews, after all they wanted to “give something back”, as Fichter puts it.

In technical jargon, this is called the “principle of reciprocity.” Or colloquially formulated: “As you do to me, so I to you.”

But the psychologist Arnd Florack, who is a professor for consumer behavior research at the University of Vienna, points out that this principle of reciprocity could also work in another, more consumer-friendly direction: “In order to balance the product gift and the selection as a test subject, the evaluator can now also be motivated be able to make a particularly well-founded assessment,” he says.

Nevertheless, the customer is also willing to remain particularly polite. He would probably package criticism nicer and soften negative judgments.

I also asked dm if it might be possible for the product testers to give slightly friendlier reviews than regular customers. Unfortunately, the drugstore chain did not want to answer this question for me.

What I continue to ask myself: why have some customers – including myself – reacted so sensitively to the “b.tan” self-tanning lotion? I check with Marq Labs, the company that developed b.tan. But there is no answer.

On the other hand, Kerstin Effers from the North Rhine-Westphalia consumer center has an idea. The chemist looked at the list of ingredients in the products “love at first tan” and “forever ever”.

You both would use the dye C.I. 19140 Tartrazine included. This can cause allergic skin reactions and even cause breathing difficulties when inhaled.

This is not the only potentially harmful active ingredient. So both products would contain polyethylene glycols.

Complicated word – but what we simply have to remember: According to the consumer advocate, these polyethylene glycols can weaken the skin barrier and make it more permeable to pollutants.

The dermatologist Marion Moers-Carpi also warns of this ingredient. The starting material, which bears the complicated name of ethylene oxide, is potentially mutagenic and carcinogenic. “It’s used in antifreeze,” she says.

And in both “b.tan” products – for a little bit of summer on the skin. But there is another ingredient that both consumer advocate Effers and Moers-Carpi warn about: dihydroxyacetone, abbreviated to DHA.

It is used for almost all self-tanners. It is only through this active ingredient that we get a tan at all when we use products like “b.tan”.

But DHA is problematic, as Moers-Carpi explains. “When this DHA comes into contact with the skin, formaldehyde splits off.” On the one hand, this is a contact allergen – some people react allergically, their skin turns red or starts to itch.

But that’s not the only problem. “Formaldehyde is carcinogenic,” says the dermatologist. She therefore advises against self-tanners with the active ingredient DHA. It is particularly risky to store them at high temperatures or for a longer period of time because this also promotes the release of formaldehyde.

Fortunately, I paid attention to cool storage during my product test. But I wonder if every customer who became aware of the product through influencer advertising was as mindful.

If not, he can at least console himself with the fact that according to self-promotion, “b.tan” contains natural ingredients and is vegan.

Buzzwords that give ordinary influencer marketing an instant semblance of sanity and mindfulness.