Biotin for hair: It’s not that powerful, and you probably don’t need it

A quick Google search is enough to confirm that biotin is a hot topic. YouTube videos call it a “super-powerful vitamin” and boast that “it made my hair grow 15 centimeters.” TikTok users echo its benefits, showing off brilliant and healthy manes. In recent years, the ingredient has become an essential element of shampoos, hair masks and nutritional supplements. But is its success deserved? What does it actually consist of?

Dr. David Saceda, a dermatologist and trichologist at the Spanish Group of Aesthetic and Therapeutic Dermatology, explains that biotin “is vitamin B7, necessary for the proper functioning of the hair cycle, the growth of hair and its maturation. When there is a deficit, the result is hair loss.” It is also an essential vitamin for cellular multiplication. Fortunately, it is present in our everyday diet, particularly in egg yolks, avocado, salmon, legumes, mushrooms and spinach. If we eat a balanced diet, we don’t need it, according to the specialist. “A varied diet fulfills the daily biotin requirement, which is 30 micrograms,” he says. Eating well is enough — or is it?

Yes, in the proper conditions. Several situations can inhibit us from absorbing the substance properly, the dermatologist explains, particularly pregnancy, the presence of digestive problems and the ingestion of alcohol or pharmaceutical drugs. “These situations can cause a deficit, and it is worth it to think about a supplement,” he says. Biotin is a fairly safe vitamin, easily eliminated by the body and with little risk of overdose, Dr. Saceda says.

The pharmacologist and nutricosmetics expert Eduardo Senante adds that biotin is water soluble, meaning that its excess is eliminated in urine. But, he adds, “if we don’t have a deficit of the nutrient, it isn’t necessary to take it. When we have more hair loss than normal, the best thing to do is to go to a dermatologist, preferably a trichologist, who, if they see it necessary, will do an analysis to see if we have a nutritional deficit.” Dr. Saceda affirms that if we don’t have a deficit, biotin will not help us at all.

Studies: Few and far between

Scientific studies can help us understand just how much good biotin can do. And, the dermatologist David Saceda says, “studies that defend its use for hair are very few and of very poor quality. The most useful in this field is by Dr. Ralph Trüeb of Switzerland, who found that 38% of women with hair problems had a biotin deficiency because of the aforementioned issues.”

Senante recommends being careful of unsupported claims about the substance. Even though it’s safe, it does have contraindications, according to the FDA. High levels of biotin due to supplements could alter results of certain medical analyses, including those related with thyroid hormones and troponin, a biomarker used to diagnose cardiac disease. And, the pharmacologist adds, “There are more and more references that relate an excess in biotin with an imbalance in the skin barrier, which can lead to acne breakouts.”

That’s the case with the vitamin’s ingestion, whether in our diet or via supplements, but what about all of those shampoos, conditioners and masks that claim to use biotin to strengthen hair? Do they work?

Shampoo and other topical products

The response comes with another question: how long do we let a shampoo act? Conditioners, on the other hand, do not typically act on the root of the hair. “The absorption of ingredients in the scalp is very limited with these products, and its action on the level of the hair follicle is practically null. I like to remind people that a shampoo will not make lost hair grow back, and it’s not made to act on the hair we still have, but on the scalp, if it is left to act for a few minutes,” Eduardo Senante says. Even so, if we want to buy a biotin shampoo, the expert recommends looking for one that also has keratin protein, which helps keep the fiber strong, and conditioning ingredients to keep it hydrated.

Biotin is not a treatment for alopecia. But there are other treatments, which Dr. David Saceda mentions: “Minoxidil and finasteride, among other pharmaceuticals. We have to use supplementary treatments, like iron supplements, to make sure everything goes well, but alopecia requires treatment prescribed by a doctor, specifically a dermatologist.”

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