About Us

Prüfengel offers authentic consumer tests in which real users share their experiences with products. Our tests are based on practical applications in everyday life and reflect the opinions of consumers. As we focus on consumer tests, we do not carry out any material, long-term or laboratory tests. The tests are carried out by 1-2 independent consumers over a period of 7-14 days. The exact test conditions can be viewed in the test plan of the respective test report – click here to go directly to the test plan.

Manufacturers provide the tested products free of charge. We charge a one-off test fee for carrying out the tests. In addition, manufacturers pay an annual licence fee for the use of the Prüfengel seal. We also receive a commission for linking to manufacturers’ websites. These remunerations have no influence on our test results or ratings.

We guarantee transparency and a fair evaluation. For a detailed insight into our comprehensive evaluation process, please click here.

R(h)ein Nutrition®
Biotin + zinc + selenium capsules

The biotin + zinc + selenium capsules from R(h)ein Nutrition support beauty from the inside out with a unique combination of biotin, zinc and selenium.
They promise not only healthy skin, hair and nails, but also normal energy metabolism and normal functioning of the nervous system. Biotin is a key building block for healthy skin and hair.
The capsules are manufactured in certified German production facilities and are vegan, which guarantees the highest quality.
R(h)ein Nutrition attaches great importance to pure food supplements without superfluous additives.
The high dosage of biotin can lead to concerns for some people. People who already take other supplements containing biotin should keep an eye on the total dose.
Overall, R(h)ein Nutrition ‘s Biotin + Zinc + Selenium capsules are a promising way to promote beauty and well-being from the inside out.
They offer a wide range of benefits for skin, hair and nails in particular.
The high-quality processing and the absence of unnecessary additives underline the quality of these products.
However, to avoid a possible overdose, you should be aware of the high dosage of biotin and carefully check whether it fits into your own diet. If in doubt, always consult a doctor.
All in all, the capsules are a promising product for anyone who wants to support their beauty routine from the inside out.

Advantages

✅ High bioavailability
✅ High quality processing
✅ Vegan and free from unnecessary additives

Disadvantages

❌ Very rare intolerance
❌ Very high dosage of biotin

The first impression

Packaging and contents

ℹ️ Here we take a closer look at packaging. Sustainability is becoming an increasingly important factor. In addition, adequate protection of the product must of course also be guaranteed. Are the contents of the packaging complete and does the manufacturer make it as easy as possible for me to use the product straight away?

CriterionRemarkScore achieved*
Product protectionProduct was not provided in the original box for the testn/A
Sustainability PackagingUnnecessary packaging waste has been avoided, the plastic film protects the product components90 points
Package contents & scopeAll parts of the product and the accessories according to the description available100 points
Instructions for useConsumption recommendation available, written in German, complete and comprehensible100 points
Total97 points
Weighting: 20%
*The maximum score is 100 points

The biotin + zinc + selenium capsules from R(h)ein Nutrition were not provided for the test in their original packaging, but in a normal shipping carton together with other products from the brand.
There are positive and negative features with regard to the sustainability of the packaging . The capsules are stored in a plastic container that is well suited for transportation.
The plastic film used around the lid protects it from unintentional opening and therefore also contributes to better product safety. The avoidance of unnecessary packaging waste is commendable.
When checking the contents and scope of the packaging, we found that all parts of the product and accessories were present as described.
The instructions for use are available in German on the back of the tin in the form of a consumption recommendation. It is complete and easy to understand.
Overall, the first impression of the packaging and contents of the R(h)ein Nutrition Biotin + Zinc + Selenium capsules is very positive.

The first time in your hand

Product processing and appearance

ℹ️ Before we start the practical test, we take a close look at the workmanship of the products. How high quality are the materials used? Are the look and feel satisfactory?

CriterionRemarkScore achieved*
Visual appearanceappealing design, visual appearance is flawless100 points
ProcessingVery good workmanship100 points
StabilityVery stable100 points
Sustainability of the productHigh-quality raw materials, vegan, made in Germany100 points
OtherAccording to Amazon, over 100 trees were planted with Aktion Baum100 points
Total100 points
Weighting: 20%
*The maximum score is 100 points
Back of the can

The external appearance of the biotin + zinc + selenium capsules from R(h)ein Nutrition is very appealing. The product presents itself in perfect condition, without scratches, dents or other damage. The surface is smooth and even and the colors are vibrant and appealing.
This undoubtedly contributes to the attractiveness of the product and leaves a positive first impression.
The workmanship of the capsules is of very high quality. There are no defects to be found and the product meets the expectations of precise and careful manufacture.
There are no sharp edges or protruding material on the capsules or the tin.
The product is fully stable. The packaging is made of hard plastic and therefore proves to be extremely robust.
Another noteworthy aspect is the sustainability of the product. The manufacturer attaches great importance to high-quality raw materials, which are selected with the utmost care and processed in certified German production facilities. This underlines the manufacturer’s commitment to quality and professionalism. The product is also vegan, which makes it accessible to a broad target group.
Production in Germany is also a commitment to environmental protection and compliance with strict quality standards.
Another positive aspect is that the manufacturer has already planted over 100 trees in collaboration with Aktion Baum. This is a commendable contribution to environmental protection and demonstrates the company’s social commitment.
To summarize, the first impression of the biotin + zinc + selenium capsules from R(h)ein Nutrition is extremely positive in terms of processing and appearance. The stability and commitment to sustainability and environmental protection are further positive features that characterize the product.

This is what our practical test showed

Does the manufacturer keep its advertising promises?

ℹ️ Our practical test has the highest relevance and therefore weighting. Here, the product has to undergo a wide range of criteria and tests. We check the functions and product promises of the test article.

CriterionRemarkScore achieved*
IngestionWith water, 1 capsule per day100 points
IngredientsZinc gluconate, sodium selenite, very high doses of D-biotin, coating agents and fillers harmless to health100 points
Offer120 capsules, no further dosages or pack sizes available90 points
StorageKeep out of the reach of children, in a cool, dry and dark place100 points
DurabilityOver two years100 points
Total98 points
Weighting: 45%
*The maximum score is 100 points

With a length of approx. 16 mm and a width of approx. 6 mm, the Biotin + Zinc + Selenium capsules from R(h)ein Nutrition are easy to swallow and can easily be taken with water. The capsules provide impressive amounts of essential nutrients.
With 110% of the NRV (nutrient reference value) for zinc in the form of zinc gluconate, 111% of the NRV for selenium in the form of sodium selenite and even 20,000% of the NRV for biotin in the form of D-biotin per capsule, they represent a high-dose food supplement.
The use of these specific nutrient forms contributes to high bioavailability .
It is also pleasing that no harmful coating agents or fillers are used.
The product is offered in packs of 120 capsules. Unfortunately, capsules with different dosages are not available, which could limit customization to individual needs.
Recommended storage in a cool, dry and dark place and protection from children are common recommendations for dietary supplements and should be adhered to in order to maintain the quality and effectiveness of the product.
With a shelf life of more than two years, the capsules have a sufficiently long shelf life.
Overall, the biotin + zinc + selenium capsules from R(h)ein Nutrition impress with their well thought-out combination of zinc, selenium and biotin.
The high bioavailability makes them a promising option for those who want to supplement these specific nutrients.
However, the limited availability of other options may be a limitation for some consumers.
Nonetheless, this product is a high-quality supplement for supporting nails, hair and skin.
However, it should be noted that it is always recommended to consult a doctor before taking such supplements.
The practical test does not provide any information on the effectiveness of the capsules, as it was not possible to test them during the intended test period.

Price/performance ratio

and ratings from consumers

ℹ️ Finally, we examine how the product compares to the competition. Can it keep up with the competition in terms of price and quality? Would we generally recommend buying it? We also look at the consumer reviews and check whether the critical and positive reviews are actually justified.

CriterionRemarkScore achieved*
Price / performance ratioAppropriate75 points
Rating cut4.3 out of 5.0 on Amazon65 points
Total70 points
Weighting: 15%
*The maximum score is 100 points

On the Amazon platform, consumers rate the product with an average of 4.3 stars.

The positive effect on nails, skin and hair is emphasized. Many users report positive changes after taking the product, particularly with regard to the strength of the nails. Skin and hair are also perceived as improved.
The high dosage of biotin, which is present in bioactive form and therefore offers good bioavailability, is also appreciated.
In addition, the capsules are described as easy to digest and easy to swallow.
They are odorless and tasteless.
Customers also praise the clear communication of the product information, including the recommended dosage and the origin of the ingredients.
On the other hand, concerns are expressed about the extremely high dosage of biotin, which is far above the recommended daily dose. This can lead to falsifications in laboratory diagnostic tests and requires caution when taking the product.
It should therefore be noted that additional biotin intake from other food supplements should be taken into account in order to avoid overdosing.
In our practical test, we found that the biotin + zinc + selenium capsules from R(h)ein Nutrition contain high-quality ingredients.
We found the well-tolerated capsules very pleasant to take and easy to integrate into the daily routine.
However, the high dosage of biotin is a double-edged sword that requires caution. It is advisable to consult a doctor before taking it, especially if other supplements are also being taken.

Prices of up to around €30 are charged on the Internet for equivalent products. Very cheap products are available from around €8 . The biotin + zinc + selenium capsules from R(h)ein Nutrition are therefore currently in the middle price segment with a price of €16.91. For the quality and performance received, the price-performance ratio is reasonable.

Overall result

WeightingScore achieved*
1. packaging & contents20%97 points
2. product processing & appearance20%100 points
3. in the practical test45%98 points
4. price/performance & consumer ratings15%70 points
Total94 points
*The maximum score is 100 points
Biotin + zinc + selenium capsules
 of the brand 
R(h)ein Nutrition®
achieved
94
Points in our test and therefore passed. The test was carried out in the test period
09/23
and is stored in our database under the licence number
230828005
. Further information on our test procedure can be found at www.pruefengel.de/testverfahren.

The practical tests are based on careful observations and do not include long-term or laboratory tests. The test judgements reflect the personal impressions and opinions of the testers who try out the products in everyday use. We would like to emphasise that these evaluations do not claim to be exhaustive and may reflect both subjective and objective impressions. The evaluations are made to the best of our knowledge and belief, without any liability being assumed for the accuracy or completeness of the test results. It is important to note that our tests are not based on legal requirements, medical effects or specific ingredients of the products. We rely on the advertising claims and information provided by the manufacturers, but use of the information is always at your own risk. Our efforts are aimed at ensuring a serious and thorough testing procedure, which has been developed in a long and professional process in close co-operation with our testers.

The practical tests are based on careful observations and do not include long-term or laboratory tests. The test judgements reflect the personal impressions and opinions of the testers who try out the products in everyday use. We would like to emphasise that these evaluations do not claim to be exhaustive and may reflect both subjective and objective impressions. The evaluations are made to the best of our knowledge and belief, without any liability being assumed for the accuracy or completeness of the test results. It is important to note that our tests are not based on legal requirements, medical effects or specific ingredients of the products. We rely on the advertising claims and information provided by the manufacturers, but use of the information is always at your own risk. Our efforts are aimed at ensuring a serious and thorough testing procedure, which has been developed in a long and professional process in close co-operation with our testers.

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Evaluation process

You can find a detailed insight into our evaluation process, which forms the basis for our product ratings, here:

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