Cancer patients warned popular supplement may interfere with treatment

FOR IMMEDIATE RELEASE: Jan. 20, 2026
NOTE TO EDITOR: Video and photos are available for download at bit.ly/45wHtTx

Key Takeaways

• Biotin supplements promoted for hair and nail growth may interfere with lab results for cancer patients, potentially affecting treatment.

• Instead of using biotin supplements, dermatologist recommends FDA-approved minoxidil for hair loss.

• For patients who choose to stay on biotin supplements, stop taking them 72 hours before blood work.
   

COLUMBUS, Ohio – For many cancer patients, hair loss is one of the most distressing side effects of their therapy. Increasingly, they have been taking oral supplements of biotin, which are marketed to consumers for their potential to improve hair regrowth and brittle nails. 

However, there is little scientific evidence that oral biotin supplements promote hair and nail growth for those living with or recovering from cancer, and they may actually interfere with lab results, said 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, or vitamin B7, is used by the body to build protein, including keratin, which is a key component of hair, skin and nails. Biotin deficiency is rare because it is readily available in everyday 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 is associate director of dermatology at The Ohio State University College of Medicine and director of the Oncodermatology Clinic, which addresses hair, skin or nail side effects from patients’ cancer treatment 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. 

Determined to raise awareness about the unintended consequences of taking biotin, Dulmage is the senior author of an article published in JCO Oncology Practice. The article urges oncologists to talk with patients about their hair loss and educate them about how biotin could affect their test results. 

Biotin supplements can affect blood work for some cancers

Biotin in particular can mask changes in prostate, thyroid, ovarian and breast cancers, she said. Some lab tests rely on a chemical reaction involving biotin so when patients take biotin supplements, lab results may falsely be high or low. 

“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.”

Like many patients, Anna Malagoli of Columbus was concerned about the side effects of her breast cancer treatment, in particular hair loss. 

“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 was determined to regain her long curly hair. She started taking biotin supplements based on information she read 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.”

Patient had inconsistent lab results while taking biotin supplements

Malagoli first learned about biotin possibly affecting lab results during an appointment with Dulmage. She was surprised but in reflecting, she said it made sense.

“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 want to continue to take biotin supplements, Dulmage recommends they stop taking them 72 hours before blood work.

“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.”

FDA-approved minoxidil is a safe, effective alternative to biotin supplements

For hair loss, Dulmage recommends patients take minoxidil instead of biotin supplements, pointing out that it is both effective and safe, except for those who are pregnant or breastfeeding. Over-the-counter minoxidil is FDA approved for hair loss and available in topical forms such as lotions or foams. 

“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 taken both minoxidil and biotin supplements and noticed less effectiveness from the biotin. 

“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.”

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