Podcast: Episode 33, Yuka, is this the best app?

Listen to the audio episode to become an expert on your sunscreen

Summary of the episode:

  • Explanation of how cosmetic product scanner apps work
  • How does Yuka work? Why is it such an effective app? Is there a better app than Yuka?
  • Why I recommend the Claire application.


1. How does it work?

Cosmetics analytics apps are mobile apps that give users information about the ingredients in cosmetics .

This is usually information related to product safety . These applications are increasingly used and are popular in France but also internationally, among them: Yuka, Inci Beauty, Clean Beauty, Mireille App for France, EWG for the United States, Think Dirty for Canada or Beauty Evolution for China.

Their operations are quite similar. These are applications that are generally downloaded for free on their smartphone, and which have access to the camera functionality of the phone. Through the application, the user can either scan the barcode of the cosmetic or directly take a photo of the list of ingredients of the cosmetic to be analyzed. The application gives a score either in the form of a fraction, on /100 for Yuka, /20 for Inci Beauty, or using a color code, or the letters of the alphabet.


When the application uses the barcode, then the analysis of the cosmetic requires that the product has been identified previously.

This is the case of Yuka. In most cases, the application involves the user . That is to say, when the user scans the barcode of a product that has never been identified, the application asks the user to enter data relating to this product.

For Yuka, you have to scan the barcode, indicate the name of the product and its brand, choose the category of the product from a list, you have to upload two photos: one of the product, one of its ingredient list, check the transcription from the ingredient list.

The analysis is very fast and can be done in an hour. After that, all users who scan the products will have access to its analysis: each ingredient is noted with a color code, with an associated description and categories .

3. The INCI photo

If the application allows to take a picture of a list of ingredients (INCI), then the analysis is carried out directly.

The product does not need to be referenced beforehand but there will not really be a product page with the name, the photo of the product etc.


1. Presentation & ingredient note

To explain how applications rate cosmetics, let's take the example of Yuka, the most downloaded application in France on iOS or Android

It launched in January 2017 in the analysis of food products and diversified in June 2018 with the analysis of cosmetic products. Yuka has a database of cosmetic ingredients, which they rate according to 4 criteria (endocrine disruptor, allergen, irritant, carcinogen) and according to 4 levels of risk (a high risk corresponds to a red color, a moderate risk is represented by a orange color, a yellow color corresponds to a limited risk and a green color to no risk).

According to them, the Yuka team relies on scientific literature to assign color notations to ingredients. It's a team of 11 people, who are computer scientists or marketers, with the added help of a nutritionist for their blog.

It goes without saying that it is difficult for a team of 11 people who are not toxicologists to analyze in detail the safety of thousands of ingredients . Namely that at European level, it is the delegation of the CSSC (Scientific Committee for Consumer Safety) to review the safety of ingredients. It is a committee made up of several dozen doctors and European professors. Suffice to say that the work done by Yuka's team is colossal.

2. Scoring of the cosmetic: the levels

After all the cosmetic ingredients are rated, the app has an algorithm that gives the rating of the finished product based on the rating of its ingredients.

The finished product has a mark out of /100. Its color is dark green if its score is between 75 and 100, it is light green between 75 and 50, orange between 50 and 25 and red below 25/100.

The algorithm is extremely harsh because the finished product contains only one red ingredient even if it is in minimal quantities then the finished product will have a red note .
In fact the color of the finished product cannot be better than the color of its worst ingredient. If your shower gel contains an orange ingredient then it will be rated orange at best. The exception is for ingredients whose color is yellow or light green, they do not force the finished product note to match the color of the ingredient.

3. The algorithm

The scoring method changes in stages. Depending on the color, the counting of points is different: if the product has no orange or red then each yellow ingredient will remove 7 points + penalties if it is noted as a carcinogen or endocrine disruptor.
If the product contains at least one orange ingredient, it will be a maximum of 49 and each additional orange ingredient will deduct 6 points, and each additional yellow ingredient will deduct 2 points, with always penalties for ingredients noted as carcinogenic or endocrine disruptors.
The maximum score for a cosmetic with a red ingredient will be a maximum of 24/100.


1. Technical limitations

One of the biggest issues is that when the app uses the barcode to reference the product, the ingredient list may not be up to date .
It should be kept in mind that the barcode is normally used by the distributor and does not store information about the list of ingredients. It's the mobile app that links the barcode to the ingredient list that was sent to it when the product was added. That is to say, the brand has no platform available to indicate a change of ingredients . If the brand reformulates their products, changes the ingredient lists but keeps the same barcodes then the application will not reflect the new ingredient lists and you will analyze a cosmetic that is not the right one.

The second problem is that when the application asks to take a photo of the list of ingredients then some ingredients may not be recognized, especially if the packaging is cylindrical and all the ingredients are not present in a single photo.

2. "The dose makes the poison"

In toxicology, one of the key principles is “It's the dose that makes the poison”. This means that our body's response to a molecule, a compound will depend on the dose to which we are exposed. Some studies show that the relationship is not always linear, but what is certain is that our body's response depends on the dose administered.
Water can be deadly , some died after drinking 6 L of water. Knowing that water can kill us, should water be noted as a risky ingredient in cosmetics? It sounds complicated.
However, water is generally the main ingredient in cosmetic creams. Knowing this, should it be rated red?
Because the route of administration and the quantity of this ingredient under the normal conditions of use of cosmetics do not correspond to a risk situation. But to assess this, you need to have access to the concentrations of the ingredients within the formula . That is to say to the formula which is confidential. Mobile cosmetics analysis applications obviously do not have access to the formula and are unable to assess the risk of ingredients in products.

Fortunately, it is the work of a toxicologist who necessarily intervenes during product development and before it is put on the market.

The law obliges the brand to request a toxicological analysis from an expert in this field by giving him access to confidential documents such as the formula, or documentation on the raw materials, and the tests which have been carried out on the finished product such as the skin irritation tests or eye irritation for example. For those interested, episode 13 goes into depth about the various tests performed on cosmetics .

This expert thus has all the keys to assess the harmlessness of the product, he is independent and signs in his name. He partly takes some responsibility.

The biggest limitation of cosmetic analysis apps is that they don't have access to the formulas of the finished products they analyze, so they don't know the concentrations of the ingredients. And without the concentration, it is impossible to scientifically assess the risk of an ingredient.

3. My recommendations

My first recommendation is to not be afraid of your cosmetics because they have been extensively tested and studied before arriving in your hands.

My second recommendation is to use an application like Claire , which does not list the ingredients but gives a description of them. It will allow you to learn more about their uses in cosmetics and their skin benefits . This application works by taking a photo of the list of ingredients, and it can have small technical hiccups such as forgotten ingredients or misinterpreted by the application.

It is educational and does not surf on fear marketing. It was developed by cosmetic experts who are the FEBEA (the Federation of BEAUTY Companies) and the SFC (the French Society of Cosmetology) .

It does not call into question the safety of the product, which had to be evaluated beforehand by a toxicologist, but it indicates the known benefits of the ingredients . Again, the app doesn't know the concentrations, it can't claim that the finished product contains enough of the raw material to receive the ingredient's benefits . It does not question the work of the toxicologist and provides the most objective information on the ingredients. That's why, it's the only app I recommend.

Also, if you ask yourself the question of the objectivity that I could have with regard to the applications, in my capacity as founder of Mastel. Know that as all my content is purely objective and that moreover Mastel skincare is rated 100/100 on Yuka, so I really have no interest in advising against the application, on the contrary. But from a scientific point of view, I don't trust mobile apps to rate/evaluate the safety of a cosmetic product.

Did you miss the last episodes? Take a look at episode 32 - Solutions against greenwashing or the 5 tips for sunscreen experts .

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My recommendations for using the best cosmetic scan application available in France. Episode 33 of Below Cosmetics.
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A chemist in the cosmetics industry for more than 5 years and a graduate of the Natural Raw Materials in Cosmetics Master's degree from ISIPCA, Julie is an expert in the development of natural cosmetic products.