Doctors warn this popular vitamin may quietly disrupt cancer care

There is little scientific evidence that oral biotin helps hair or nail growth in people undergoing or recovering from cancer treatment. More concerning, it may interfere with medical testing, according to Brittany Dulmage, MD, an oncodermatologist at The Ohio State University Comprehensive Cancer Center — Arthur G. James Cancer Hospital and Richard J. Solove Research Institute.

Biotin, also known as vitamin B7, helps the body produce proteins such as keratin, which supports hair, skin and nails. However, true biotin deficiency is uncommon because the vitamin is widely found in foods like fruits, vegetables, meats, eggs and dairy products.

“People have the misconception that biotin supplements are harmless and there’s no reason not to take them. The reality is that the supplements may cause inaccurate lab results, resulting in a delay or change in patients’ treatment plans,” she said.

Dulmage also serves as associate director of dermatology at The Ohio State University College of Medicine and leads the Oncodermatology Clinic, where patients receive care for hair, skin and nail side effects caused by treatments such as chemotherapy, immunotherapy or targeted therapy.

“More than half the patients who come to see me with a problem related to hair loss are on a supplement that they’ve started on their own after learning about it online, by word of mouth and sometimes even at the advice of their doctor,” she said.

To highlight these concerns, Dulmage authored a paper in JCO Oncology Practice urging oncologists to discuss hair loss openly with patients and explain how biotin could affect test results.

How Biotin Can Distort Cancer Lab Results

Biotin can interfere with certain blood tests used to monitor cancers, including prostate, thyroid, ovarian and breast cancers. Some of these tests rely on chemical reactions that involve biotin, so taking supplements can cause results to appear higher or lower than they truly are.

“Biotin does not actually change the levels of hormones in the body, but it interferes with the way those levels could be checked when blood work is done,” she said. “For some of the hormones such as prostate specific antigen, PSA, or thyroid stimulating hormone, TSH, it may falsely suppress or lower those levels, potentially masking cancer recurrence in cancer survivors. For reproductive hormones including estrogen and testosterone, it may falsely elevate levels, resulting in delayed therapy.”

A Patient’s Experience With Biotin and Lab Results

Anna Malagoli of Columbus, like many cancer patients, worried about losing her hair during breast cancer treatment.

“Your hair is very much a part of you. One of the first things you ask is ‘Am I going to lose my hair?’ It’s such an important thing for people — not everybody looks good with no hair,” she said.

After her cancer went into remission, she wanted to restore her long curly hair and began taking biotin supplements after reading about them online.

“The amount of information on the Internet can lead you in different directions. I was taking so much biotin it’s not even funny,” she said. “Nobody mentioned one word that biotin vitamins or minerals or supplements could interfere with your treatment or your testing.”

Inconsistent Test Results Raise Concerns

Malagoli only became aware of the issue during a visit with Dulmage. Looking back, she said the explanation fit her experience.

“My lab results were inconsistent. They just didn’t balance out with what I was feeling so that was a red flag. I think it had to do with the supplements I was taking,” she said.

For patients who choose to keep using biotin, Dulmage advises stopping it at least 72 hours before scheduled blood tests.

“The challenge is that not all blood work is planned so you may not be able to hold your biotin. Biotin can also impact the levels of troponin, which is a marker of whether or not someone is having a heart attack,” she said. “Obviously, you’re not planning to have a heart attack so you can’t hold biotin before troponin levels are checked. This is why I recommend to patients — think about not taking it at all, especially since very few people are biotin deficient.”

Safer Options for Hair Loss During Cancer Treatment

Instead of biotin, Dulmage suggests using minoxidil to address hair loss. This treatment is FDA approved, widely available over the counter, and comes in topical forms such as lotions and foams. It is considered safe and effective for most people, though it is not recommended during pregnancy or breastfeeding.

“If you have been trying minoxidil for several months and not seeing any improvement or want to know about other options, see a dermatologist. There are many other types of treatments that may be an option,” she said.

Malagoli has tried both approaches and found that minoxidil worked better for her.

“I don’t know if my body just doesn’t assimilate the supplements as well, but minoxidil is definitely more effective long-term,” she said. “I would say it’s super important to listen to your doctors and not just do your thing.”