Biotin deficiency: when it actually occurs

The short answer: a diet-related biotin deficiency is rare in Germany. The German Nutrition Society (DGE) names four situations for it — a very one-sided diet with a lot of raw egg white, artificial nutrition without added biotin, high alcohol consumption, smoking and certain medicines, and inherited defects of biotin metabolism. Outside these cases the measured intake of the population is already within the range of the reference value. So anyone who notices brittle nails or more hair in the brush does not yet have an indication of a biotin deficiency — the symptoms are unspecific, and statistically the vitamin is almost never the cause at that point.

That does not make the question superfluous, it shifts it. Not "do I have too little?" but "am I in one of the groups in which too little occurs at all?" is the usable question in front of the shelf.

Why a deficiency hardly arises from food

Biotin is widely distributed in the diet. In foods of animal origin it is mostly protein-bound as biocytin, which is split in the small intestine and absorbed quickly; in plants it occurs partly in free form. On top of that the gut flora produces biotin itself — how much of that is actually used, however, cannot be quantified cleanly and therefore does not enter into any reference value.

The second German National Nutrition Survey determined a mean intake of 40 µg per day in women and 46 µg in men. The D-A-CH estimated value for adults is 40 µg, for breastfeeding women 45 µg. The two almost coincide — and that is not a coincidence but method: because robust dose-response data are missing, the DGE derives the estimated value from the average intake in the population, in which no deficiency symptoms occur.

In practice this means that an ordinary mixed diet covers the estimated value without anyone having to pay attention to it. Which foods do the work is shown in Biotin in foods.

The triggers that are actually documented

Trigger	What happens	How common
A lot of raw egg white	Avidin binds biotin in the gut	rare, only with one-sided habits
Artificial nutrition without added biotin	Intake ceases	clinical situation
Alcohol, smoking, anticonvulsants	Absorption impaired, breakdown promoted	relevant with sustained use or long-term therapy
Inherited enzyme defects	Biotin is not released, or more is needed	biotinidase deficiency approx. 1 in 80,000

Raw egg white: the egg-white injury

The best-known trigger is at the same time the easiest to avoid. Raw egg white contains avidin, a glycoprotein that forms a very stable complex with biotin. This complex is not split in the gastrointestinal tract — so the bound biotin is not available to the body. Anyone who eats or drinks very large amounts of raw egg white over a longer period can trigger a deficiency dermatitis this way, the so-called egg-white injury (product information for Biotin-ratiopharm 5 mg).

What matters is the state of the egg: heating inactivates avidin. After boiling or frying, biotin absorption is no longer restricted, and the egg — the yolk above all — becomes one of the better biotin sources there is. Under usual eating habits the matter is settled with that; it only becomes a problem where raw eggs are part of the daily routine.

An exact limit — from how many raw egg whites a day it becomes critical — is named neither by the DGE nor by the product information. Both speak of "high consumption" or "very large amounts", an honest wording behind which lies the simple fact that nobody carries out this experiment systematically in humans.

Artificial nutrition without added biotin

If a person is fed parenterally over a longer period and the solution contains no biotin, intake ceases completely. That is exactly what biotin-containing medicines exist for: among other things they are authorised for the supply of vitamins in the context of parenteral nutrition (Rote-Hand-Brief on biotin, 2019). This is a clinical situation, not a question of diet — the treating clinic takes it into account.

Alcohol, smoking and medicines

The DGE names three factors that impair biotin absorption or promote its breakdown: high alcohol consumption, smoking and taking anticonvulsants — medicines intended to prevent epileptic seizures. This is the point at which a deficiency is most likely to arise in everyday life without anyone eating anything unusual.

The order of magnitude matters: this is about sustained patterns, not about a glass of wine or a short course of medication. And the consequence belongs in the consulting room, not on the shelf — anyone taking anticonvulsants permanently clarifies an additional vitamin intake with their doctor instead of starting it themselves.

Inherited defects of biotin metabolism

Biotinidase is the enzyme that releases protein-bound biotin again. If it is missing, the best diet is of little use. A biotinidase deficiency occurs with a frequency of about 1 in 80,000 and shows itself, among other things, in hearing and vision disorders, developmental disorders, skin changes, hair loss (alopecia), seizures, low blood pressure and ketoacidosis. That is why the German newborn screening tests for it: without an early, lifelong supply of free biotin in pharmacological doses — the DGE names 5 to 20 mg per day — a fatal course is possible.

Alongside this stands multiple carboxylase deficiency, in which a genetic defect raises the biotin requirement. Both are cases for medicines with a defined strength — biotin medicines are available in Germany with 5 mg per tablet, for instance — not for food supplements. Where the boundary between the two categories runs, and what that means for high microgram figures on the shelf, is described in High-dose biotin.

What a deficiency looks like

The symptoms named by the DGE are: growth retardation, skin changes, hair loss and neurological disorders such as movement disorders and lethargy. Disorders of the immune system can occur as well. For a pronounced deficiency the product information adds complaints affecting the skin and skin appendages, psychiatric symptoms and gastrointestinal complaints.

The problem with this list: not a single item is specific. Hair loss has dozens of causes, skin changes likewise, lethargy all the more so. A symptom from the list is therefore a reason to look into the causes — but no proof that biotin of all things is missing. What the authorised claims about hair actually allow and what they do not is set out in Biotin for hair.

Why biotin status is hard to measure

The obvious move would be to settle the question in the laboratory. In principle, biotin status can be described via concentrations of biotin and various breakdown products in blood and urine as well as via functional parameters. Only: so far there are neither uniform analytical methods for these biomarkers nor uniform assessment criteria, and no sufficient data on them — that is the reason why the DGE derives the reference values from population intake instead of from a status marker.

As a rough guide: for free and weakly bound biotin in blood the product information gives 200 to 1,200 ng/l as normal, and urinary excretion as 6 to 50 µg in 24 hours. A generally accepted threshold below which a deficiency begins does not follow from this, however.

On top of that comes a trap that hits precisely the people who take an interest in the subject: a biotin supplement already being taken distorts many blood tests. Numerous immunoassays are based on streptavidin-biotin binding; free biotin in the blood interferes with this reaction, upwards or downwards depending on the test design. In 2019 the European Medicines Agency saw sufficient evidence for such interactions from 150 µg of biotin per day. So anyone who first takes a high-dose supplement and then has blood drawn is not measuring their status but a confounder — which values are affected and what interval is needed is described in Biotin and blood tests.

What this means for the purchasing decision

The DGE is brief on this point: since there is no widespread deficiency in the population, no general recommendation for biotin supplements can be made; preventive effects of an intake above the reference values are not established on current data. That is not a warning but a classification: for most people a supplement closes no gap, because there is none.

The question remains reasonable for the groups further up — and for anyone who wants the estimated value secured independently of the menu. For that, amounts in the range of the nutrient reference value of 50 µg are enough; they are at the same time below the 150 µg threshold from which laboratory tests can be disturbed.

Our Biotin 10,000 µg sits deliberately far above that — it is a high single dose and not a way of covering requirements; anyone choosing it should keep the laboratory appointment in mind. Further strengths and combinations are in the Biotin category. Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle.

The authorised claims for biotin are set out word for word in Regulation (EU) No 432/2012 and apply from 7.5 µg per daily dose:

Biotin contributes to normal energy-yielding metabolism.

Biotin contributes to normal macronutrient metabolism.

Biotin contributes to normal functioning of the nervous system.

Frequently asked questions

I am losing more hair than before — is that a biotin deficiency? Usually not. Hair loss is on the list of symptoms, but it is entirely unspecific; a diet-related biotin deficiency is rare in Germany and then has one of the triggers named above. Anyone who has none of them is better off looking for the cause elsewhere — the DGE states explicitly that the structure and condition of hair and nails cannot be improved by an intake above the estimated value.

How many raw eggs would be a problem? The German sources do not name a figure. They speak of "high consumption" of raw egg white over a longer period. A raw egg in a batter or occasionally in a drink does not fall under that — and boiled eggs not at all, because heating inactivates the avidin.

Can I have a biotin deficiency established in the laboratory? Only to a limited extent. Uniform analytical methods and assessment criteria for the biomarkers are missing. And anyone already taking a high-dose supplement may be distorting the test itself — biotin interferes with immunoassays based on streptavidin-biotin binding.

Do pregnant women need more biotin? Not according to the D-A-CH reference values: for pregnant women the same estimated value of 40 µg per day applies as for other adults. Only during breastfeeding does it rise to 45 µg — by the amount given off in breast milk.

Sources: DGE, "Selected questions and answers on biotin", as of 10 September 2025 (occurrence, triggers, symptoms, biotinidase deficiency, intake data from the National Nutrition Survey II, assessment of supplements) · BfR, "Proposals for maximum levels of biotin in foods including food supplements", 2021 · Product information for Biotin-ratiopharm 5 mg, as of March 2019 (avidin/egg-white injury, multiple carboxylase deficiency, blood and urine values) · Rote-Hand-Brief on biotin-containing medicines, 2019 · EMA/PRAC, Recommendations on signals, January 2019 · Regulation (EU) No 432/2012, Annex.