According to approved EFSA claims, biotin supports the maintenance of normal skin and normal hair, provided that a portion provides at least 7.5 µg. For nails, however, there is not a single approved EFSA claim, even though biotin is marketed in Germany as the best-selling "nail vitamin." According to the German Nutrition Society (DGE), the actual daily requirement for adults is only 40 µg, yet many supplements on the market contain 5,000 to 10,000 µg—125 to 250 times that amount. This article explains in detail whether this is actually useful and for whom.

What is biotin (vitamin B7) and what does the body actually need it for?

Biotin, formerly also known as vitamin H or vitamin B7, is a water-soluble B vitamin. In the body, it functions as a coenzyme for several carboxylases—enzymes that catalyze key steps in fat, carbohydrate, and amino acid metabolism. As a result, biotin is involved in energy production from macronutrients, fatty acid synthesis, and gluconeogenesis. Since skin cells and hair follicles are among the tissues with particularly high cell division rates, biotin has traditionally been associated with skin and hair health, even if this connection, as shown later in this article, must be viewed with more nuance than advertising claims suggest.

The body cannot produce biotin itself to any significant extent. While a small amount is produced by the gut flora, its contribution to overall supply is considered rather minor and difficult to quantify. Therefore, the main supply comes from the diet. According to the DGE, good sources of biotin include liver and kidney, nuts and sunflower seeds, cooked egg yolk, soybeans, oats, and mushrooms (with 200 g of button mushrooms providing about 29 µg). In Germany, dairy products are considered the most important overall source of biotin because they are consumed regularly and in larger quantities, even if their biotin content per 100 g is comparatively low.

As a B vitamin, biotin belongs to a group of eight water-soluble vitamins that work together in energy metabolism but each have independent, EFSA-verified functions. Unlike fat-soluble vitamins such as A, D, E, and K, excess biotin is not stored in body fat but is excreted via the kidneys once requirements are met. This mechanism is one of the main reasons why the DGE does not expect any additional efficacy from very high intake levels: what the body cannot metabolize is simply excreted rather than stored in hair or nails.

Does biotin really work against hair loss?

The EFSA has officially approved the statement "biotin contributes to the maintenance of normal hair," which is one of seven approved biotin claims (the full list follows below). The exact wording is important here: the claim speaks of "maintenance," not "promotion" or "improvement." It therefore describes that biotin is required for a normal hair structure, not that additional intake beyond requirements leads to more or thicker hair.

After reviewing the available study data, the consumer protection agency (Verbraucherzentrale) reached a clear conclusion: "The study situation regarding skin and hair health is weak, and the conditions are sometimes questionable." Most studies showing an improvement in hair growth through biotin supplementation were conducted on individuals with a proven biotin deficiency—a rare situation in Germany. For people who already have an adequate biotin supply, the DGE expects no additional effect on hair structure, as the body does not store excess biotin in hair follicles but excretes surplus amounts renally.

This also explains why many user reports on high-dose biotin preparations are contradictory: those who actually had a mild, often unrecognized deficiency may experience a noticeable improvement. Those who are already well-supplied and experiencing hair loss for other reasons (more on this below) will notice no change from taking even more biotin.

Biotin for skin: What is actually proven?

There is also an approved claim for skin: "biotin contributes to the maintenance of normal skin," supplemented by the statement "biotin contributes to the maintenance of normal mucous membranes." These approvals are based on the well-documented role of biotin in the lipid metabolism of the skin and on classic deficiency symptoms, which include scaly, reddened skin changes. However, the same limitation as with hair applies here: the claim describes the maintenance of already normal skin function given an adequate supply, not a cosmetic improvement in people who are already well-supplied.

In its scientific assessment, the EFSA itself noted that biotin intake in the general population is usually sufficient, which is why no further effect on skin or hair is to be expected from additional intake. This is an unusually clear statement from an authority that also approved the claim itself, and this nuance is often lost in many marketing texts.

Biotin for nails: The uncomfortable fact check

This is where the greatest gap between marketing and regulatory approval lies: there is not a single EFSA-approved biotin claim for nails, even though biotin is marketed in Germany primarily as a "nail vitamin." This is remarkable because, unlike the topic of hair, there is actually a randomized, placebo-controlled, double-blind study with 60 participants regarding brittle nails, in which 2.5 mg of biotin daily improved nail growth behavior and clinical nail quality—a result that, according to an analysis by the Pharmazeutische Zeitung, could be classified as largely proving a therapeutic benefit for reduced nail quality. Despite this single positive study, the EFSA has not yet approved a corresponding claim, presumably because a single, medium-sized study does not meet its requirements for robust overall evidence for permanent, EU-wide approval. For consumers, this means: an effect on brittle nails is more plausible than for hair, but it is not regulatorily secured.

The comparison with two other trace elements is interesting: Zinc is currently the only micronutrient for which the EFSA has approved claims for all three areas simultaneously, namely "zinc contributes to the maintenance of normal hair," "zinc contributes to the maintenance of normal skin," and "zinc contributes to the maintenance of normal nails." Selenium also has approved claims for hair and nails ("selenium contributes to the maintenance of normal hair" and "selenium contributes to the maintenance of normal nails"). Those who want to do something specifically for brittle nails will find zinc or selenium to be the legally and scientifically more substantiated option, rather than biotin alone. The Veyt Biotin High-Dose Complex contains selenium in addition to biotin—a detail that is more relevant to product selection than the name of the product might suggest.

For better perspective, it is worth comparing the three nutrients most frequently mentioned in advertising for skin, hair, and nails, which have different levels of approval:

Zinc is therefore the only one of the three nutrients with a full "triple approval." Anyone looking for a supplement that covers all three areas simultaneously with an approved claim should look specifically at the zinc content, not just the biotin amount on the label. This does not rule out a sensible combination of biotin, zinc, and selenium—on the contrary: since all three nutrients have different, complementary mechanisms in energy metabolism and antioxidant protection, a combined intake in an amount appropriate to one's needs is biologically more sensible than an isolated, high-dose biotin preparation.

What do the individual studies really show? An honest look at the data

Most beauty guides on biotin refer generally to "studies" without naming them. A closer look at the research actually cited shows why the EFSA remained cautious regarding hair and did not approve a claim for nails despite one positive study:

Nails: The aforementioned double-blind, placebo-controlled study with 60 participants and 2.5 mg of biotin daily showed improvement in both objective measurements of nail growth behavior and subjective clinical assessment of brittle nails. This is the methodologically strongest human study available on biotin and nails, but it is a single study, not a series of independently replicated investigations.

Hair: A frequently cited study by Floersheim examined 93 patients with hair loss taking biotin. An analysis of this study in the Pharmazeutische Zeitung attests to "significant methodological flaws": there was no standardized diagnosis of the hair loss, no trichogram for objective hair root analysis, and the assessment was based solely on a yes/no self-assessment by participants without a placebo control group. In addition, 10 of the 93 participants simultaneously used other hair-growth-promoting products, which further biased the results. The sobering conclusion of the analysis: there are no investigations into biotin and hair loss that meet strict scientific criteria. This explains why, although the EFSA claim for hair is approved (it is based on the established physiological mechanism and classic deficiency symptoms), a specific "biotin against hair loss" claim for non-deficiency situations does not exist.

Skin: According to the same analysis, controlled studies on the connection between biotin and skin conditions such as seborrheic dermatitis are almost completely lacking. A single, uncontrolled observation reported clinical improvement in 25 children taking 5 mg of biotin daily, while at the same time, investigations on 60 patients with seborrheic skin lesions found no pathologically low biotin plasma levels, which fundamentally calls the assumed mechanism of action (biotin deficiency as the cause) into question.

In summary: The evidence is strongest for nails, methodologically weakest for hair, and hardly controlled for skin—a finding that is exactly the opposite of the marketing priority of many products, which advertise primarily with hair.

What is the actual biotin requirement according to the DGE, and why do supplements contain so much more?

In 2020, as part of the revised D-A-CH reference values, the German Nutrition Society (DGE) published estimated values for adequate biotin intake. These are expressly estimates, not established requirement figures, because the data situation is insufficient for a more precise derivation. Nevertheless, they provide a realistic orientation as to how low the actual daily requirement is in comparison to the dosages standardly found on the market.

The large gap between the requirement and the common market dose is not a safety issue—more on this in the section on BfR limits—but it is also not proof of efficacy. Higher doses were not assessed by EFSA as necessary for the approved claims; the minimum amount for labeling with one of the seven claims is only 7.5 µg per serving, 15 percent of the EU nutrient reference value of 50 µg.

Legally, biotin supplements in Germany are classified as food supplements under the Food Supplement Regulation (NemV), not as medicinal products. Manufacturers must indicate the amount contained per recommended daily serving on the packaging and may only use the officially approved EFSA claims—a requirement that is not always met in practice, as evidenced by the numerous unsubstantiated nail-related promises in the market. Unlike medicinal products, food supplements do not undergo official efficacy testing before sale; there is merely an obligation to notify the Federal Office of Consumer Protection and Food Safety (BVL). The responsibility for accurate, EFSA-compliant advertising claims therefore lies primarily with the manufacturer itself.

Which biotin effects are officially recognized by EFSA?

Unlike many plant-based food supplements, EFSA has officially approved several health claims for biotin under Regulation (EU) No 432/2012. We intentionally list them here in their full original wording:

• "Biotin contributes to normal energy-yielding metabolism", approved from 7.5 µg of biotin per daily serving
• "Biotin contributes to normal functioning of the nervous system", approved from 7.5 µg of biotin per daily serving
• "Biotin contributes to normal macronutrient metabolism", approved from 7.5 µg of biotin per daily serving
• "Biotin contributes to normal psychological function", approved from 7.5 µg of biotin per daily serving
• "Biotin contributes to the maintenance of normal hair", approved from 7.5 µg of biotin per daily serving
• "Biotin contributes to the maintenance of normal mucous membranes", approved from 7.5 µg of biotin per daily serving
• "Biotin contributes to the maintenance of normal skin", approved from 7.5 µg of biotin per daily serving

What these claims explicitly do not say: There is no approved statement that biotin stops hair loss, accelerates hair growth, hardens nails, or improves acne. These formulations nevertheless frequently appear in product descriptions and influencer advertising without an EFSA basis. Reputable providers limit themselves to the approved "maintenance" formulations and refrain from "improvement" or "enhancement" promises.

Biotin deficiency: Who is really affected and how is it recognized?

A classic biotin deficiency is considered rare in Germany because a balanced diet generally covers the low daily requirement of 40 µg. The DGE identifies the regular consumption of large amounts of raw egg whites as a primary risk factor for a deficiency: it contains the glycoprotein avidin, which binds biotin in the intestine and blocks its absorption—an effect that largely disappears when heated (cooked, fried). Other risk factors include heavy, chronic alcohol consumption, smoking, and the long-term use of certain antiepileptic drugs that can affect biotin metabolism.

Typical deficiency symptoms, according to the DGE, include growth disorders, skin changes, hair loss, and neurological complaints, and in severe cases, impairments to the immune system. A rare congenital disorder, biotinidase deficiency, is routinely covered in Germany by newborn screening and treated early. In the case of unexplained, persistent hair loss or brittle nails without a recognizable external cause, medical clarification is more sensible than non-specific biotin supplementation on suspicion, if only because other, more common causes (see below) could be overlooked.

Caution: Biotin can falsify laboratory results

A safety note that is frequently missing from high-dose biotin supplements: many modern lab tests, including those for thyroid values (TSH, fT3, fT4) and cardiac markers such as troponin, use biotin-streptavidin binding as a technical principle. High-dose biotin intake can thereby falsify these tests and lead to falsely high or falsely low readings, with potentially relevant consequences for medical diagnosis in individual cases. The Federal Institute for Risk Assessment (BfR) points to documented cases of test falsification starting from an intake of 150 µg of biotin per day—an amount that many commercially available products with 5,000 to 10,000 µg per serving exceed by many times.

The BfR has therefore deliberately not set a maximum amount for biotin in food supplements because no toxicologically substantiated upper limit can be derived from the available data, and no harmful health effects occurred in observations at standard intake levels. Instead, the authority recommends labeling on the product that advises users to inform medical personnel about taking biotin supplements before a blood draw. Anyone who regularly takes high-dose biotin and is due for a blood test should typically pause intake for a few days beforehand after consulting with their doctor.

What really helps against thin hair and brittle nails, if not biotin alone?

Since an isolated biotin deficiency is rare, it is worth looking at more common causes for persistent hair loss or brittle nails before spending money on high-dose biotin. In dermatological practice, diffuse hair loss is one of the most common reasons for consultation among women, and the underlying causes are in the majority of cases nutritional or hormonal and cannot be explained by an isolated vitamin deficiency. The following overview categorizes the most relevant causes based on how frequently they actually occur and how well they can be clarified by laboratory diagnostics:

• Iron deficiency: One of the most common causes of diffuse hair loss in women, especially with heavy menstrual bleeding, during pregnancy, or with intense endurance sports. More on this in the guide Iron for Women: Requirement, Dosage, and Signs of a Deficiency.
• Zinc or selenium deficiency: Both trace elements, unlike biotin, actually have approved EFSA claims for nails and are among the first candidates for targeted cause clarification in cases of brittle nails.
• Thyroid dysfunction: Both hyperthyroidism and hypothyroidism can manifest through hair loss and brittle nails and should be clarified medically, especially because high-dose biotin, as described above, can falsify these very thyroid tests.
• Protein intake: Hair and nails consist mainly of the structural protein keratin. A consistently insufficient protein intake can directly affect hair and nail quality, regardless of biotin status.
• Genetic predisposition and hormones: Androgenetic hair loss (hereditary) and hormonal changes—such as around menopause, in the cycle phase after birth (postpartum hair loss), or when discontinuing hormonal contraception—cannot be influenced by biotin, as other mechanisms than vitamin supply are at play here.

Especially for women, a structured clarification of causes is worthwhile because several of these factors, above all iron deficiency and hormonal shifts, overlap over the course of life. A ferritin value (iron stores) and a basic thyroid value (TSH) are among the most sensible first laboratory tests for persistent, diffuse hair loss before high-dose biotin is taken on one's own, which, as described above, could subsequently falsify these very thyroid values.

Biotin supplements in comparison: Shot or capsules?

Anyone who decides on targeted supplementation, for example because a medically confirmed deficiency exists or to ensure the maintenance of already normal skin and hair function, has a choice between different dosage forms. The two Veyt formulas differ primarily in format and additives:

Detailed background on the efficacy of collagen as an ingredient, including the fact that EFSA has not approved a skin claim for collagen either, can be found in the guide Collagen Dosage: How Many Grams Per Day Really Work. The actually approved collagen formation statement is carried by vitamin C, by the way, not collagen itself; read more in the guide Vitamin C Dosage: How Many mg Per Day Really Make Sense.

Biotin during pregnancy and breastfeeding: What women should know

During pregnancy, biotin metabolism changes noticeably; among other things, the breakdown of biotin in the body increases. However, the DGE currently does not derive an increased reference value from this; according to the DGE, pregnant women have the same estimated value of 40 µg per day as non-pregnant adults. During breastfeeding, the value increases to 45 µg per day because biotin is passed to the child through breast milk.

A balanced diet generally covers this requirement without problems. Anyone considering a combination preparation with biotin, for example as part of a more comprehensive micronutrient supply, should keep an eye on the total intake from all sources and discuss intake with their attending gynecologist or midwife, as with any food supplement during pregnancy and breastfeeding. This is especially true if a pregnancy multivitamin is already being taken, to avoid unintended dual supply.

Also relevant for many women is so-called postpartum hair loss, a diffuse, usually temporary hair loss in the months after birth. The cause is primarily the drop in estrogen levels after pregnancy, which causes more hair follicles to enter the resting phase (telogen phase) simultaneously than usual—a hormonal mechanism that has nothing to do with biotin status. It is generally self-limiting and resolves on its own within a few months. Biotin supplementation cannot accelerate this hormonally driven process, even if it often coincides in time with a general depletion of nutrient reserves, such as iron stores, which is why a targeted clarification of causes is more sensible in this phase of life than non-specific biotin intake on suspicion.

What to look for when buying a biotin supplement?

Since the legal framework for nail claims is missing and dosages vary significantly, it is worth looking at the following criteria when purchasing: transparent declaration of all micronutrients contained, including exact quantity per serving; independent laboratory testing for purity and heavy metals; manufacturing according to recognized quality standards such as HACCP or GMP; as well as realistic, non-exaggerated advertising claims that are oriented toward the actually approved EFSA claims rather than unsubstantiated nail or growth promises. Combination preparations that contain zinc, selenium, or collagen alongside biotin cover the topic of skin, hair, and nails more broadly than an isolated biotin supplement alone because they also provide the nutrients with an actual nail claim.

Another often overlooked criterion is the dosage form in relation to your own everyday life: A liquid shot like the Veyt Biotin High-Dose Complex provides the daily dose all at once and is easy to integrate into a morning routine, while capsules allow for finer dosage control and can be carried on the go more easily without refrigeration. Anyone who already takes a multivitamin, a pregnancy supplement, or individual B vitamins in addition to biotin supplements should keep an eye on the total amount from all sources—not to avoid a danger, because as described, no toxicological upper limit is known for biotin, but to realistically assess unnecessary double costs and the laboratory test falsification described above.

Veyt Biotin formulas at a glance

Conclusion: Is biotin useful for hair, skin, and nails?

Biotin is undeniably important for metabolism, and the EFSA claims regarding hair, skin, the nervous system, and energy metabolism are real and scientifically founded. For healthy people without a proven deficiency, however, high-dose supplementation is, according to the DGE and EFSA, no guarantee for visibly thicker hair or harder nails, and for nails, an approved claim is completely missing. More sensible than taking biotin in isolation and in high doses is often a combination with zinc or selenium—the two nutrients with an actual nail claim—combined with a clarification of more common causes like iron deficiency or thyroid problems, before money and hope are invested in biotin alone.

Frequently asked questions about biotin

Sources: German Nutrition Society, FAQ Biotin, German Federal Institute for Risk Assessment, Maximum level suggestions for biotin, Consumer Center, Does biotin ensure healthy skin, shiny hair, and strong nails?, Pharmazeutische Zeitung, Biotin only helps the nails. This article does not replace individual medical advice.