From the hair salon to the dermatologist’s office to Facebook mom groups, it seems like everyone is talking about hair growth treatments. Hormonal shifts (like those that come with pregnancy and perimenopause), stress, post-COVID fallout, rapid weight loss from GLP-1s, aging—there are countless reasons women feel they’re shedding more strands than usual.
And they’re desperate for solutions.
Among the most popular options: oral hair growth supplements—blends of vitamins, minerals, and herbal ingredients touted to spur growth—and topical or oral drugs, available over the counter and by prescription. The category has exploded. In fact, the global hair loss treatment market is expected to hit $2.22 billion this year and surpass $3 billion by 2030, according to market intelligence and consulting firm Coherent Market Insights.
Meet the experts: Chesahna Kindred, MD, is a dermatologist in Marriottsville, Maryland, who specializes in hair loss. Melissa Piliang, MD, is a dermatologist and hair loss specialist at the Cleveland Clinic. Karan Lal, DO, is a dermatologist in Scottsdale, Arizona.
Yet as interest in these treatments grows, so do concerns. Late last year, a case study linking a widely used nutraceutical (a fancy word for supplement) to liver injury was published in the American Journal of Gastroenterology (AJG). And just a few months ago, the FDA issued a warning about the topical drug finasteride, following numerous reports of men experiencing devastating side effects from spraying it on their scalps.
It’s caused some alarm—and confusion. For a long time now, the most common question experts would get about these therapies was, “Do hair growth treatments work?” Now, it’s, “Are they safe?”
Let’s start where many women do—with supplements.
Supplements: Natural Isn’t Always Better
Many women assume supplements are safer than drugs—after all, they’re “natural,” right? But doctors push back on that assumption. “While natural supplements can be effective, it’s a common misconception that ‘natural’ means ‘safe,’” says Chesahna Kindred, MD, a dermatologist in Marriottsville, Maryland, who specializes in hair loss.
In the U.S., supplements are regulated by the FDA, but as a food category—not as drugs. That means there’s no rigorous pre-approval process to vet them for safety or effectiveness before they hit the shelves. The FDA oversees manufacturing, labeling, and marketing claims, but that’s about it. “Many supplements contain excessively high doses of ingredients, sometimes exceeding ten times the recommended daily allowance,” says Dr. Kindred.
Take biotin (vitamin B7), a popular ingredient in hair supplements. In 2019, the FDA issued a warning about high doses of biotin interfering with lab tests—especially thyroid panels and cardiac enzyme tests used to diagnose heart attacks. “I recommended biotin for years, but I’ve stopped because of this risk,” says Melissa Piliang, MD, a dermatologist and hair loss specialist at the Cleveland Clinic. “If someone comes to the ER with chest pain, doctors look at these cardiac markers to decide if it’s a heart attack. If biotin is skewing the results, you might not get the treatment you need.” It’s an error that could be deadly.
And the concerns don’t stop there. In a 2020 paper published in the Journal of the American Academy of Dermatology, a panel of experts issued a call to action to improve hair growth supplement safety. “Quality data, including randomized controlled trials examining dietary supplementation for hair growth in well-nourished adults, are limited,” the authors wrote. Among their biggest concerns:
- Biotin, for its interference with lab tests
- Vitamin E, which can increase bleeding risk in high doses
- Saw palmetto, a botanical often included in mystery doses and at extremely high levels, that may cause abnormal genital development in male fetuses
- Vitamin A, which can also cause hair loss when over-supplemented—ironic, right?
- Selenium, which in excess can cause hair and nail loss and brittleness, along with GI and neurological symptoms
Then came the AJG case study: A 26-year-old woman with a history of obesity developed jaundice and was diagnosed with liver damage. She’d been taking Nutrafol daily for five months. Her labs were normal before starting the supplement, and they improved after she stopped, so her doctors attributed her condition to Nutrafol. The supplement contains multiple ingredients with potential for liver toxicity, including turmeric, ashwagandha, horsetail, saw palmetto, kelp minerals, and resveratrol, according to the paper.
If you’re among the one million people taking Nutrafol, don’t panic—but don’t ignore the warning, either. “I don’t think the average person taking Nutrafol is at major risk—it was one report. It’s not like these are flooding in,” says Dr. Piliang. “But it’s important to be thoughtful about what we put in our bodies,” she says. “I have patients afraid to take well-studied medications, but they’ll take supplements with 20 ingredients we haven’t really studied—that’s a harder risk profile to assess.”
I have patients afraid to take well-studied medications, but they’ll take supplements with 20 ingredients we haven’t really studied—that’s a harder risk profile to assess.
With any supplement you take, treat it like a medication, says Dr. Kindred. “When purchasing a supplement, the brand should educate you about potential side effects,” she says. “If they are unable to do so, I recommend consulting your doctor.” Your doctor can tell you if it might interact with any other medications (including other vitamins and supplements) you’re taking. “However, it’s important to note that while many supplements have been available for years, some have undergone little to no clinical research, meaning data on their safety may not be readily available.”
Prescription Pitfalls
The side effects don’t stop at supplements—prescription treatments also come with potential downsides. The difference? Your doctor generally knows what to expect—and who’s a good candidate—when it comes to Rx options. But these drugs are no longer prescribed exclusively by dermatologists during in-office visits. And that’s where things can go wrong.
Earlier this year came the FDA warning about adverse effects tied to topical finasteride being sold through tele-health platforms. Between 2019 and 2024, the agency tracked 32 adverse event reports. In most cases, these platforms were sending patients compounded topical finasteride—usually mixed with minoxidil, another hair loss drug that works via a different pathway. Neither topical finasteride nor these compounded versions are currently FDA-approved.
Related Stories
The reported side effects mirror those seen with the oral version of finasteride: anxiety, depression, fatigue, insomnia, brain fog, and sexual dysfunction in men, including decreased libido. According to the FDA, some patients said they weren’t warned about any side effects at all—others were told there was no risk. “Some consumers expressed they became very depressed, suffering with pain, and that their lives were ruined because of these symptoms,” the alert stated.
Dermatologists say the issue isn’t necessarily the medications—it’s how and to whom they’re being prescribed. “When patients come into the office, whether they’re starting oral or topical therapy, we screen them very heavily,” says Karan Lal, DO, a dermatologist in Scottsdale, Arizona. “You want someone who asks the right questions, monitors for side effects, and confirms you’re a good candidate. I don’t think that’s happening on these platforms—they’re handing these drugs out like candy.”
On their own, finasteride and minoxidil are both well-studied and typically well-tolerated, adds Dr. Piliang. “The vast majority of patients do quite well without significant side effects,” she says. “With topical finasteride, we rarely see someone develop a headache, dizziness, or heart palpitations—and if they do, we adjust the dose.”
Minoxidil, originally a blood pressure medication, can lower blood pressure in high doses. “The amounts we use for hair loss are so low that shouldn’t be a concern,” Dr. Piliang says. “But if someone has a history of heart issues or arrhythmias, I send them to a cardiologist first.”
The concern? That level of screening just isn’t happening on these fast-track platforms.
Serious Treatments, Serious Considerations
If your supplements or medications are working, no one’s saying stop. But talk to your doctor to make sure you understand the risks and that your therapy of choice plays nice with whatever else you’re taking. And if you’re thinking about starting a medication, see a board-certified dermatologist—not just a website with a slick logo and same-day shipping.
“It’s so important for people to be informed when making decisions about hair growth treatments or supplements,” says Dr. Piliang. “Whatever choice you make, you should understand how it might affect your health. If something doesn’t feel right, speak up—and it’s crucial to let your doctors know you’re taking it.”
Bottom line: If the potential side effects are more alarming than the hair shedding, it’s worth thinking long and hard about your fix of choice.
Writer Krista Bennett DeMaio has covered beauty and health for over 20 years. Her work has appeared in women’s magazines and websites, including Women’s Health, Oprah Daily, Allure, Cosmopolitan, HealthCentral, and Prevention.com. She’s also the founder of Pretty Local, a platform that keeps tabs on local beauty and wellness.