Biotin, Lab Interference and Safer Options for Cancer-Related Hair Loss

Hair changes related to cancer treatment can lead patients to explore supplements that promise regrowth or strengthening, frequently without realizing those products may carry unintended clinical consequences, according to Dr. Brittany Dulmage, a physician and associate professor of dermatology at the Ohio State University Wexner Medical Center.

New research is drawing attention to biotin, a widely used vitamin found in many hair and nail supplements, and its potential to disrupt laboratory testing that oncologists rely on to monitor disease status and guide care. These findings, published in JCO Oncology Practice, underscore the need for greater awareness of supplement use during and after cancer treatment, particularly when lab results play a central role in treatment decisions.

Dulmage also serves as associate director of dermatology and director of the Oncodermatology Clinic at The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute.

As senior author of the study, Dulmage investigated how biotin supplementation can interfere with commonly used laboratory testing and outlined safer, evidence-based approaches to managing cancer-related hair loss. She sat down with CURE to discuss her research and its implications.

CURE: Why do so many patients who are experiencing cancer-related hair loss turn to biotin supplements? What are the common misconceptions about their safety during treatment?

Many patients turn to biotin supplements because of their perceived safety. They are easy to obtain from the supplement aisle at a local drugstore; it seems like there is not a lot of risk associated with them. Cancer patients are often looking for things that are lower risk regarding the potential for interaction with their treatments. They are often cautious about adding more prescription medications to their regimen because they are already undergoing treatment with chemotherapy, immunotherapy or other therapies. This may cause hesitation toward prescription medications, whereas supplements often seem to be lower risk and are perceived to be more natural.

How can biotin interfere with routine blood tests? Why is this risky for patients undergoing active cancer treatments?

Biotin does not change hormone levels in the body; it does not cause your body to produce more or less of a hormone. Instead, when blood is drawn, biotin can bind to some of the reagents (the chemicals added to the test tube) and interfere with the lab results. This can cause some readings to appear too high and others to appear too low.

Some of the most pertinent interferences occur with thyroid hormone levels, which can be misestimated. It can lead to falsely low prostate-specific antigen (PSA) levels, which are a marker of prostate cancer. Furthermore, it can lead to misinterpretations of sex hormones like testosterone and estradiol, a type of estrogen. These are important because oncologists may use these labs to track response to therapy. In the case of PSA, it is used to track the risk or presence of recurrence.

These labs are used to make treatment decisions. For a woman undergoing breast cancer treatment, estradiol levels are measured to determine if she is pre- or post-menopausal, which may dictate the treatment she receives for hormone-receptor-positive breast cancer.

Additionally, biotin interferes with labs that monitor the side effects of cancer therapy. Thyroid function, in particular, is often impacted by various types of immunotherapy. If your thyroid hormone levels are misrepresented, it may appear as though you are or are not having a reaction to immunotherapy when the opposite is true.

Can biotin potentially alter treatment decisions?

Even if it does not alter treatment decisions, it has the potential to lead to additional unnecessary tests or imaging. If a patient were to receive falsely incorrect lab values, they may need to undergo additional unnecessary labs or imaging to further work up those false results.

What safer evidence-based options do you recommend for patients who are concerned about hair loss or changes to skin and nails during treatment?

As far as hair loss is concerned, one of our safe, readily available options is minoxidil, which is available over the counter, typically as a foam or a solution. It is safe when applied topically, except when used by pregnant or breastfeeding women. Other than for that patient group, minoxidil is very safe for the majority of patients and is readily available as an over-the-counter option.

Beyond that, there are some oral medicines that may be options depending on the type of cancer and the type of hair loss being treated. These would typically be prescribed by a dermatologist or someone who is comfortable managing different forms of hair loss. There are some prescription medicines that we avoid in patients who have hormone receptor-positive cancers, in particular, breast cancer. Therefore, for each individual patient, it is important to determine their cancer type and their hair loss type, as there are different patterns and forms of hair loss, and then ultimately unite those two factors to decide on a safe and effective medication plan.

What conversations should patients have with their oncology team before starting any over the counter supplements, even those that seem harmless?

I think a couple of things are important. First, you want to know if the supplement you are taking or plan to take has evidence to support its use. In the case of biotin, not only does it have the potential to interfere with lab results, but there is very little evidence that it is actually helpful for hair growth. There are no objective studies using measures of hair regrowth over time that show any demonstrated benefit to biotin.

While very small studies show that patients may subjectively feel better on it, there is no evidence that it actually helps grow hair. Relatively recently, within the last few years, the American Academy of Dermatology stated that we need to stop telling patients to take biotin because it does not have a proven benefit, and this applies to all patients, not just those with cancer.

On top of that, it carries the risk of interfering with blood work. Importantly, you want to know if a supplement has any demonstrated benefit for the specific side effect you are planning to treat. Another important consideration is whether there is a risk of interference beyond just blood work. Supplements may alter the way treatment drugs are metabolized. Some supplements may interfere with how your body breaks down other medications, leading to levels of those medicines that are either too high or too low.

Most oncology teams include a clinical pharmacist who can review a planned supplement alongside a patient's medication list. They can highlight any “red flags” or risks for drug-drug interactions, where the two substances interact with each other.

What risks does biotin pose beyond cancer-specific laboratory testing?

There are two other types of labs that biotin interferes with. It may not be as immediately relevant for cancer patients, but they are important. One is that it interferes with troponin levels, which are a marker of whether someone is having a heart attack. Number two is that it interferes with a lot of commercially available pregnancy tests. So, they can interfere with the likelihood of getting a positive pregnancy test if someone is pregnant.

The reason why I point those two things out, the troponins, is because in the paper we talk about how if a patient knew they were taking biotin and wanted to continue it, and knew they had blood work coming up, they could hold the biotin for 72 hours before the blood work, and that would reduce any effect the biotin would have on the blood work. The problem with troponins is that no one plans to have a heart attack, so no one thinks, “I’m going to have a heart attack, so I better hold my biotin for 72 hours before the heart attack.” And that’s problematic, because if you show up at the hospital and you are possibly having a heart attack, they check those troponin levels, they are going to potentially be altered by the biotin, and you would have had no idea that you were supposed to hold it.

I think that’s another important interaction to point out, even though that’s not specific to cancer patients. The other thing I would just add is that I was driven to write this paper and to kind of bring this to light because one of the main parts of my practice is taking care of patients with hair loss from cancer. Patients who are dealing with hair loss from breast cancer therapies, and a lot of them come in on biotin at their very first visit. If you ask what they have tried for hair loss, supplements are the number one thing people have tried if they have tried something before they came in. Pretty much all of the supplements that are marketed as hair, skin or nail vitamins or supplements contain biotin.

I had this conversation over and over and over again with new patients, and I wanted to write a paper that would try to be directed at the oncology audience, because patients who are undergoing cancer treatment are often going to talk to their oncologists before they ever make it to a dermatologist. And I wanted to make sure that oncologists were aware of this risk, because I think many oncologists assume that biotin is relatively safe because it is readily available and it is a B vitamin, and that there is not a lot of risk in it.

We wanted to bring this potential effect on lab values to light.

References

1. “Cancer Patients Warned Popular Supplement May Interfere with Treatment,” by The Ohio State University Comprehensive Cancer Center. News release; Jan. 2026.
2. “Biotin Supplements for Hair and Nail Regrowth: A Caution for Oncologists,” by Layna Mager, et al. JCO Oncology Practice.

Transcript has been edited for clarity and conciseness.

For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.