Who Found Biotin, and Why Raw Egg White Caused a Vitamin Mystery

Raw egg white made animals sick because avidin binds biotin and blocks its absorption. Paul György's vitamin H turned out to be biotin, a molecule other groups had named separately. High-dose biotin now matters for some blood tests, which can read falsely high or low.

Biotin has no single discoverer. Its history starts with a diet problem: animals fed large amounts of raw egg white lost hair and developed skin rashes, even though eggs are among the foods with the most biotin, according to the [NIH Office of Dietary Supplements](https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/). The answer took decades to assemble. It turned out to be a protein in the white that binds biotin tightly. The same kind of bond is also why some blood tests now misread people taking high-dose biotin. ## Egg white made animals sick before biotin had a name In 1916, W. G. Bateman reported that large amounts of raw egg white in experimental diets caused hair loss and dermatitis in rats, according to a [1998 chapter by G. F. M. Ball](https://doi.org/10.1007/978-1-4899-3414-7_12). Margarete Boas took up the question in rats. According to PubMed, her 1924 papers tested egg white as the sole source of nitrogen for young growing rats ([DOI](https://doi.org/10.1042/bj0180422)), and her 1927 paper on how drying affected the nutritive value of egg white followed ([DOI](https://doi.org/10.1042/bj0210712)). [Bristol's chemistry page](https://www.chm.bris.ac.uk/motm/biotin/biotinh.htm) credits Boas with coining the term "egg-white injury" for the skin rash, hair loss and loss of muscle coordination the rats developed. ## Vitamin H was named for hair and skin Food clues drove many vitamin discoveries, and our [B12 history](/blog/history/history-of-vitamin-b12-from-liver-cure-to-cobalamin) starts with one. Paul György, working at Case Western Reserve University in Cleveland, took up egg-white injury in the 1930s. He called the factor vitamin H, from the German words for hair (*Haar*) and skin (*Haut*). The name did not last. Other groups had isolated the same molecule from foods such as yeast and named it co-enzyme R or biotin. Science carried the identity question through 1940. According to PubMed, three papers from György, Vincent du Vigneaud and colleagues on whether vitamin H was biotin appeared that year, in March, July and December ([DOI](https://doi.org/10.1126/science.91.2358.243), [DOI](https://doi.org/10.1126/science.92.2377.62), [DOI](https://doi.org/10.1126/science.92.2400.609)). Working with Esmond Emerson Snell, György fed chicks egg white alone and found them short of biotin, even though the diet contained it. Mixing egg white with yeast extract, which is rich in biotin, lowered the biotin measured in the mixture. Bristol says that pointed to a factor in the white that removed biotin. According to PubMed, the group's 1941 *Science* paper was titled "Egg-white injury as the result of nonabsorption or inactivation of biotin" ([DOI](https://doi.org/10.1126/science.93.2420.477)). ## Avidin locks biotin away The protein in raw egg white is avidin, a name built from "avid" and biotin, because it grabs biotin eagerly, according to Bristol. The bond between the two is among the strongest known non-covalent bonds. NIH's Office of Dietary Supplements describes avidin as a glycoprotein in raw egg white that binds dietary biotin tightly and prevents its absorption. Cooking denatures avidin, so cooked egg does not interfere in the same way. Cooked egg still supplies biotin: | Food (ODS serving) | Biotin (mcg) | % Daily Value | |---|---|---| | Beef liver, cooked, 3 oz | 30.8 | 103 | | Egg, whole, cooked | 10.0 | 33 | | Salmon, pink, canned in water, 3 oz | 5.0 | 17 | Source: NIH ODS biotin fact sheet, Table 2. The Daily Value and the adult adequate intake are both 30 mcg a day. ## Five enzymes depend on biotin ODS says biotin is a cofactor for five carboxylases: propionyl-CoA carboxylase, pyruvate carboxylase, methylcrotonyl-CoA carboxylase, and acetyl-CoA carboxylases 1 and 2. They catalyze steps in the metabolism of fatty acids, glucose and amino acids. Biotin also has roles in histone modification and gene regulation. For context, see our [NAD longevity guide](/health/nad-longevity-complete-guide) and [mitochondrial health guide](/health/mitochondrial-health-complete-guide). Deficiency is rare. ODS says severe deficiency has never been reported in healthy people eating a normal mixed diet, and average intakes in other western populations, about 35 to 70 mcg a day, appear to meet the need. Biotinidase matters at birth. ODS says the enzyme releases free biotin from food proteins. According to PubMed, the same enzyme recycles biotin, and untreated biotinidase deficiency can cause neurological and skin symptoms that treatment at birth can prevent ([DOI](https://doi.org/10.1016/j.gene.2015.10.010)). ODS says all newborns in the United States and many other countries are screened for it. ## Hair and nail claims rest on small studies Signs of deficiency include skin rashes, hair loss and brittle nails, which is why supplements are often promoted for hair, skin and nails, per ODS. ODS says those claims are supported, at best, by a few case reports and small studies. Three nail studies had no placebo group. One included 22 women with brittle nails and 10 healthy volunteers taking 2.5 mg a day for 6 to 15 months. Another reported firmer nails in 41 of 45 patients after an average of 5.5 months. The hair evidence comes from case reports in children with uncombable hair syndrome, a rare hair shaft disorder. The skin evidence comes from case reports in infants. ## High-dose biotin can change blood test results Many lab tests use biotin-streptavidin technology, and extra biotin in the blood can distort them. According to PubMed, a 2017 *JAMA* study gave six healthy adults 10 mg a day of biotin for seven days. Interference appeared in 9 of 23 biotinylated assays (39%) and in none of 14 assays without biotin ([DOI](https://doi.org/10.1001/jama.2017.13705)). Five of eight biotinylated competitive immunoassays read falsely high, and four of 15 sandwich immunoassays read falsely low. The authors described it as a preliminary study. ODS also cites case reports of falsely abnormal thyroid results in people taking 10 to 300 mg a day. It also reports that, according to FDA, a patient with a high biotin intake died after a troponin test, used to help diagnose a heart attack, gave a falsely low result. FDA advises providers to ask patients about biotin-containing supplements and to consider biotin interference when lab results do not match the clinical picture. ## Bottom line The egg white story shows that a nutrient can be present in food and still be unavailable to the body. The lab-test problem is the newer lesson, and the practical step is simple: tell the clinician who orders your blood work about any biotin you take. The bond that once locked biotin away in egg white is the same kind labs use to tag and measure proteins, which is also why high-dose biotin can throw those results off. ## Frequently asked questions ### Why did raw egg white make some animals sick? Raw egg white contains avidin, a protein that binds biotin tightly and prevents absorption, according to NIH ODS. Rats fed egg white as their only protein source developed skin rashes, hair loss and loss of muscle coordination in the 1920s experiments, and Margarete Boas named the syndrome egg-white injury. Cooking denatures avidin, which is why cooked egg does not block absorption in the same way. ### What did the name vitamin H refer to? Paul György named vitamin H for the German words for hair (*Haar*) and skin (*Haut*), because he linked the factor to healthy hair and skin. The name did not last. Other groups had isolated the same molecule under other names, including co-enzyme R and biotin, and Science papers in 1940 tested whether they were identical. Biotin became the official name, and the vitamin was reassigned as vitamin B7. ### Who isolated biotin, and from which food? No single person did. A 1998 chapter by G. F. M. Ball reports that Kögl and Tönnis isolated a crystalline growth factor from egg yolk in 1936 and named it biotin. Other groups isolated the same molecule from foods such as yeast under other names. The chapter's abstract sums up the sequence: the 1936 yolk isolation, the 1940 identity finding, and the structure established in 1942 by du Vigneaud's group. ### How does avidin in raw egg white block biotin? Avidin has a pocket that holds one biotin molecule in each of its four identical units, and the bond is among the strongest known non-covalent bonds, according to Bristol's chemistry page. NIH ODS describes avidin as a glycoprotein in raw egg white that binds dietary biotin tightly and prevents its absorption. Heat denatures avidin, so cooked egg does not interfere with absorption in the same way. That is why the injury was a raw-diet problem. ### Which biotin-dependent enzymes matter for metabolism? ODS lists five carboxylases that depend on biotin: propionyl-CoA carboxylase, pyruvate carboxylase, methylcrotonyl-CoA carboxylase, and acetyl-CoA carboxylases 1 and 2. They catalyze steps in the metabolism of fatty acids, glucose and amino acids. Biotin also has roles in histone modification and gene regulation. Deficiency is rare, and ODS says severe deficiency has never been reported in healthy people eating a normal mixed diet. ### Why do some lab tests change with high-dose biotin? Many immunoassays use biotin and streptavidin to link antibodies to a readout, and extra biotin in the blood can interfere with that link. According to PubMed, a 2017 JAMA study of six healthy adults taking 10 mg a day for a week found interference in 9 of 23 biotinylated assays. ODS reports thyroid results falsely pointing to an overactive thyroid in case reports. FDA advises providers to ask about biotin supplements and to consider interference when results do not fit the clinical picture. ### What do the hair and nail studies actually show? Mostly case reports and small studies. NIH ODS says the claims are supported, at best, by a few case reports and small studies. The three nail studies had no placebo group, and the hair evidence comes from children with uncombable hair syndrome. ODS says future studies are needed to show whether biotin supplements help hair, skin or nails, especially in healthy people. The well-established part is deficiency, which causes hair loss, skin rashes and brittle nails. What extra biotin does for people who already get enough is the open question. ## Next reads - [Mitochondrial health: the complete guide](/health/mitochondrial-health-complete-guide): the reference page for the energy pathways where biotin-dependent enzymes do their work. - [The history of vitamin B12, from liver cure to cobalamin](/blog/history/history-of-vitamin-b12-from-liver-cure-to-cobalamin): another vitamin whose discovery began with a food clue. ### Related reading - [the B-complex origin story, from one factor to eight](/blog/history/history-of-the-b-complex-from-one-factor-to-eight) - [the B5 origin story, from everywhere vitamin](/blog/history/history-of-pantothenic-acid-b5-from-everywhere-vitamin)