Nobody mentioned biotin could interfere with your treatment or testing
In the quiet desperation that follows hair loss during cancer treatment, many patients have turned to biotin supplements — a remedy that feels harmless and hopeful, yet carries a hidden cost. Oncologists at Ohio State University are now warning that biotin can distort the very blood tests used to detect cancer recurrence, silently bending the numbers that guide life-or-death treatment decisions. The problem is not malice but misinformation: patients seeking dignity and normalcy online, unaware that a common vitamin could obscure what their doctors most need to see. In this collision between emotional need and medical precision, the call is for open conversation between patients and physicians before the supplements ever reach the medicine cabinet.
- More than half of cancer patients presenting with hair loss are already self-medicating with biotin before their oncologists even know — a quiet epidemic born from internet searches and well-meaning friends.
- Biotin distorts blood tests for prostate, thyroid, breast, and ovarian cancers, suppressing some markers and inflating others, meaning a recurrence could go undetected or a treatment plan could shift based on entirely false data.
- One breast cancer survivor discovered her lab results had been inconsistent for months, only realizing in retrospect that the biotin she'd been taking in large doses had been quietly corrupting her numbers all along.
- The danger extends beyond cancer monitoring — biotin also interferes with troponin tests used to detect heart attacks, a scenario where patients cannot simply pause their supplements and wait.
- Oncologists are now urging patients to abandon biotin entirely and turn instead to FDA-approved minoxidil, a topical treatment proven more effective for hair regrowth and free of laboratory interference.
Hair loss during cancer treatment cuts deeper than appearance — it is a visible wound to identity, and the urgency to reverse it drives many patients online, where biotin supplements are marketed as a natural, harmless solution. Thousands of cancer patients have quietly begun taking them, often without mentioning it to their doctors.
Brittany Dulmage, an oncodermatologist at Ohio State University's Comprehensive Cancer Center, began noticing the pattern in her clinic: more than half of patients arriving with hair loss concerns were already self-medicating with biotin. The problem, she explains, is not toxicity — it is interference. Biotin can skew the blood tests oncologists rely on to monitor cancer, producing falsely suppressed readings for PSA and TSH, or artificially elevated hormone levels. The cancer itself may be unchanged, but what the tests reveal becomes unreliable, potentially delaying or misdirecting treatment.
One Columbus patient, Anna Malagoli, experienced this firsthand after her breast cancer went into remission. Determined to restore her hair, she began taking large doses of biotin she'd researched online. No one had warned her of the risks. When her lab results came back inconsistent with how she felt physically, she and Dulmage eventually traced the distortion back to the supplements.
The stakes are compounded by the fact that some tests cannot be scheduled around supplement use. Biotin also interferes with troponin, the marker for heart attacks — an emergency that offers no advance notice for patients to pause their vitamins.
Dulmage now recommends that cancer patients avoid biotin altogether, noting that true deficiency is rare and the supplements offer little real benefit for hair regrowth. For those seeking a genuine solution, minoxidil — an FDA-approved topical treatment available over the counter — offers a safer and more effective path. Malagoli herself found it superior. Dulmage published her findings in JCO Oncology Practice, calling on oncologists to raise the conversation about hair loss proactively, before patients turn to the internet for answers that could quietly compromise their care.
Hair loss during cancer treatment is not merely a cosmetic problem. For many patients, it becomes a crisis of identity—the visible marker of illness that strips away normalcy and confidence. So when hair begins to fall out, the search for solutions becomes urgent. Online, the answer appears simple: biotin supplements, widely marketed as a natural way to restore hair and strengthen nails. Thousands of cancer patients have turned to them, often without telling their doctors.
But oncologists are now sounding an alarm. Brittany Dulmage, an oncodermatologist at Ohio State University's Comprehensive Cancer Center, has seen the problem firsthand in her clinic. More than half of her patients who come in with hair loss concerns are already taking biotin supplements they've started on their own—found online, recommended by friends, sometimes even suggested by well-meaning physicians who didn't know better. The trouble is not that biotin is toxic. The trouble is that it interferes with the blood tests that oncologists use to monitor whether cancer is returning.
Biotin, also known as vitamin B7, helps the body produce keratin, the protein that makes hair, skin, and nails strong. It's found naturally in eggs, meat, dairy, fruits, and vegetables. True biotin deficiency is rare. For most people, taking extra biotin does nothing to improve hair growth. Yet the supplements have become ubiquitous in cancer communities, promoted as harmless and simple. "People have the misconception that biotin supplements are harmless and there's no reason not to take them," Dulmage said. "The reality is that the supplements may cause inaccurate lab results, resulting in a delay or change in patients' treatment plans."
The interference is subtle but serious. Biotin can skew blood tests used to monitor prostate, thyroid, breast, and ovarian cancers. Some of these tests rely on chemical reactions that involve biotin, so when a patient is taking supplements, the results come back wrong—sometimes falsely high, sometimes falsely low. For prostate-specific antigen (PSA) and thyroid-stimulating hormone (TSH), biotin can suppress the readings, potentially masking a cancer recurrence that a patient and their doctor would otherwise catch. For reproductive hormones like estrogen and testosterone, it can artificially elevate levels, leading doctors to delay or change treatment decisions based on false data. Biotin doesn't actually change what's happening in the body. It just changes what the tests can see.
Anna Malagoli of Columbus learned this the hard way. After her breast cancer went into remission, she became determined to regrow her long, curly hair. She found information online about biotin and started taking it—a lot of it. "The amount of information on the Internet can lead you in different directions," she said. "Nobody mentioned one word that biotin vitamins or minerals or supplements could interfere with your treatment or your testing." When she saw Dulmage for a follow-up appointment, her lab results were inconsistent, not matching what she felt physically. Looking back, she realized the biotin had been throwing off her numbers all along.
The challenge for patients is that not all blood work can be planned around supplement use. Dulmage points out that biotin also interferes with troponin, a marker used to detect heart attacks. A patient can't simply stop taking biotin before a troponin test because heart attacks don't announce themselves in advance. This is why Dulmage now recommends that cancer patients simply avoid biotin supplements altogether, especially since so few people actually need them. "Think about not taking it at all," she said.
For patients who want to address hair loss, there is a safer option: minoxidil, an FDA-approved topical treatment available over the counter in lotions and foams. It is effective and generally safe, except for pregnant or breastfeeding women. Malagoli has tried both treatments and found minoxidil superior. "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. Dulmage published her findings in a study in JCO Oncology Practice, urging oncologists to discuss hair loss openly with patients and explain how biotin supplements can compromise the very tests that keep them safe. The message is straightforward: listen to your doctors, not the internet.
Notable Quotes
People have the misconception that biotin supplements are harmless. The reality is that the supplements may cause inaccurate lab results, resulting in a delay or change in patients' treatment plans.— Dr. Brittany Dulmage, oncodermatologist at Ohio State University Comprehensive Cancer Center
My lab results were inconsistent. They just didn't balance out with what I was feeling so that was a red flag.— Anna Malagoli, breast cancer patient
The Hearth Conversation Another angle on the story
Why does biotin specifically interfere with cancer monitoring tests when so many other supplements don't?
Biotin gets involved in the actual chemical reactions that these tests use to measure hormone levels. It's not that it's toxic—it's that it hijacks the test itself. The test can't see the real number because biotin is in the way.
So a patient could be in real danger and not know it because their numbers look fine?
Exactly. If biotin is suppressing PSA levels, a man with prostate cancer recurrence might get a normal reading. He goes home thinking he's clear when he's not. That's months of undetected cancer.
Why do so many cancer patients turn to biotin if it doesn't actually work for hair regrowth?
Because hair loss is devastating—it's the visible proof of illness. Patients are desperate. They find testimonials online, they see it marketed as natural and safe, and no one tells them it's a problem until something goes wrong.
Could doctors have prevented this by talking to patients about it earlier?
That's exactly what Dulmage is pushing for. Most oncologists weren't trained on this issue. They didn't know biotin could interfere with their own tests. Now that word is getting out, the conversation needs to happen at the first sign of hair loss.
Is minoxidil a perfect solution then?
It's much better—it's FDA-approved, it actually works, and it doesn't mess with blood tests. But it takes time and patience. Some patients won't see results for months. That's why the conversation matters so much. If doctors explain the real options and the real risks, patients can make an informed choice instead of just grabbing whatever they find online.