Biotin
Biotin (vitamin B7) is a B vitamin that five enzymes need to process fat, sugar and protein. Adults need 30 mcg a day in the US and 40 mcg in the EU, which a normal diet with eggs, meat, fish or seeds usually covers.
30 µga day for adults, adequate intake (US)
40 µg a day for adults in the EU (EFSA adequate intake)
Upper limit · none set, because no harm has been shown from high intakes
- Richest food 31µg in 3 oz of cooked beef liver
- Everyday source 10µg in one cooked egg
- Supplements Also a source some hold thousands of mcg per capsule
- Blocked by Avidin in raw egg white; cooking destroys it
Daily amount: the US adequate intake for adults aged 19 and over (NIH). Food figures from the NIH Office of Dietary Supplements; the Caltide food library has no biotin figures yet.
Food Sources of Biotin
Animal foods lead, eggs and liver above all. Most fruit and vegetables have under 1 mcg a serving.
| Food | Serving | Biotin |
|---|---|---|
| Beef liver, cooked | 3 oz (85 g) | 30.8µg |
| Egg, whole, cooked | 1 large | 10.0µg |
| Salmon, pink, canned | 3 oz (85 g) | 5.0µg |
| Pork chop, cooked | 3 oz (85 g) | 3.8µg |
| Hamburger patty | 3 oz (85 g) | 3.8µg |
| Sunflower seeds, roasted | 1/4 cup | 2.6µg |
| Sweet potato, cooked | 1/2 cup | 2.4µg |
| Almonds, roasted | 1/4 cup | 1.5µg |
| Spinach, boiled | 1/2 cup | 0.5µg |
| Broccoli, fresh | 1/2 cup | 0.4µg |
Bacteria in the large intestine also make biotin, but how much of it the body absorbs is not known.
What Is Biotin (Vitamin B7)?
Biotin is a water-soluble B vitamin. Its job is narrow and essential: it is the coenzyme for five carboxylases, enzymes that add a carbon dioxide unit to other molecules. Those steps let the body build fatty acids, make glucose between meals and break down several amino acids, including leucine.
Biotin also appears to play a part in gene regulation and cell signaling, but that role is much less understood than its work in the carboxylases.
How the Body Absorbs Biotin From Food
In food, most biotin is bound to protein. Digestion frees it with the help of an enzyme called biotinidase, and the small intestine then absorbs the free vitamin. People born without enough biotinidase cannot recycle biotin; US newborn screening checks for this, and lifelong biotin supplements treat it.
Raw egg white is the one food that works against it. It contains avidin, a protein that grips biotin so tightly the gut cannot take it up. Cooking breaks avidin down, so a cooked egg is a source of biotin while a raw-egg habit, two or more raw whites a day for months, has caused deficiency.
Biotin Supplements
Biotin comes in multivitamins, B-complex tablets and biotin-only products, usually as free D-biotin, which is absorbed almost completely. Some products sold for hair, skin and nails hold thousands of micrograms per capsule, far beyond the 30 to 40 mcg adults need.
To put a large dose in food terms: a 10,000 mcg capsule holds as much biotin as about 1,000 cooked eggs, at roughly 10 mcg an egg. No upper limit has been set, because high intakes have not been shown to cause harm, but the dose matters for one practical reason below.
Common Biotin Mistakes
Taking it for hair without a deficiency. Thinning hair and a red, scaly rash around the eyes, nose and mouth are signs of a real shortage. In people who are not deficient, there is little evidence that extra biotin makes hair or nails grow better.
Forgetting to mention it before a blood test. Many lab tests use biotin as part of how they measure. High-dose biotin in the blood can make results for thyroid hormones, troponin (a heart attack test) and others read falsely high or low. Tell the doctor or lab you take it.
Assuming only animal foods supply it. Liver and eggs lead, but sunflower seeds, sweet potato and almonds also supply biotin. Deficiency is very rare in people who eat a varied diet; the groups at risk are listed below.
Who Is Most Likely to Be Low in Biotin
Biotin status often falls during pregnancy and breastfeeding, the same stretch when the need for folate peaks. Long-term heavy drinking blocks absorption. The seizure medicines carbamazepine, phenytoin, phenobarbital and primidone speed biotin breakdown. Another B vitamin with a central role in turning food into energy is pantothenic acid (vitamin B5).
Sources: NIH Office of Dietary Supplements, EFSA. Not medical advice.
Biotin in Caltide
- Not totaled yetFood databases rarely list biotin, so Caltide does not add it up from the foods you log. The vitamins it does total, such as folate, appear in the Nutrition tab, and every food in the food library shows its full breakdown.
Biotin Sources and References
The figures and claims on this page are checked against these sources.
Questions About Biotin
Adults need 30 mcg a day in the US (adequate intake) and 40 mcg in the EU (EFSA). Breastfeeding raises the US figure to 35 mcg.
Liver and eggs. A 3 oz serving of cooked beef liver has about 31 mcg and one cooked egg about 10 mcg, according to the NIH. Salmon, pork and seeds give smaller amounts.
There is little evidence that they do in people who are not deficient. Hair loss and a scaly rash are signs of a real shortage, which is rare, and they clear when biotin is restored.
Yes. High doses can make some lab tests read falsely high or falsely low, including thyroid tests and troponin, a test for heart attacks. The US FDA has warned about this. Tell your doctor before a blood test if you take biotin.
Raw egg white does. It contains avidin, a protein that binds biotin so the gut cannot absorb it. Eating two or more raw egg whites a day for months has caused deficiency. Cooking destroys avidin.
No upper limit has been set, because no harm has been shown from high intakes from food or supplements. The practical risk of large doses is the lab test interference.
People born with biotinidase deficiency, people with long-term heavy alcohol use, and pregnant or breastfeeding women, whose biotin status often drops. Some seizure medicines also lower biotin levels.
Not yet. Food databases rarely list biotin, so Caltide does not total it from logged foods.
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