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Over the past several years, a plethora of new supplements have emerged on the scene, promising to boost human longevity and preserve youthfulness. Now, longevity doctors are scrambling to get people to slow down.

“In our clinic, we are de-prescribing,” Dr. Andrea Maier, a leading longevity doctor who runs both a private and a public longevity clinic in Singapore, told Business Insider. “We first have to diagnose what’s wrong, what somebody needs, and that might differ.”

Maier, also a professor of medicine and functional aging at the National University of Singapore, is one of several longevity medicine doctors who told BI that they are recommending patients stop taking many of the supplements they have learned about online.

“People think that more helps more, and it’s not the case,” Dr. Evelyne Bischof, who practices longevity medicine in China, Switzerland, and Israel, told BI. “There are interactions, there are side effects.”

Bischof and other longevity medicine practitioners say the trend toward overdoing it has been supercharged in recent years by more aggressive and flashy online marketing of longevity supplements. Ads on Facebook, books by longevity influencers, along with gyms and resorts are touting antiaging fixes.

According to a recent McKinsey survey, demand for healthy aging products is soaring; 70% of American consumers across all age groups are spending more in this category than they used to post-pandemic.

Doctors like Maier and Bischof say supplements can slowly build up to dangerous health issues, impacting vital organs like the kidneys and the liver or interacting with other drugs and supplements in toxic combinations.

Increasingly, they are seeing concerning results from blood, urine, and other tests on patients who take many different products. Overdoing supplements can hurt your health hand with lots of different supplements in it More isn’t always more when it comes to taking supplements Strauss/Curtis/Getty Images

In the past, patients typically hadn’t invested in healthy aging supplements on their own. They would learn about them for the first time from their longevity medicine doctor, said Bischof, who serves patients at hospitals in Shanghai and Tel Aviv, as well as in her own VIP concierge longevity medicine business. Related stories

Things have shifted since the pandemic. In the public clinic where she works in Israel, she estimates that 20% of patients come in with a laundry list of longevity supplements in their regimen, most of them too highly dosed.

“Five years ago, it was really the opposite,” Bischof said. “It was trying to convince a patient to actually take a supplement — besides the vitamins.”

In her practice, she has seen through clinical testing how supplements can build up in vital organs. One 40-year-old patient who “really overdid” his longevity supplement doses had a biological age four years older than his actual age, as measured by his blood. He also had suboptimal kidney function.

He didn’t want to quit taking the pills (Bischof did not name the products), but his subsequent blood tests were only looking worse and worse, and his biological age kept creeping up.

Eventually, Bischof was able to convince the patient to stop taking his longevity supplements. “And, of course, the biological age reversed,” she said.

Others have noticed the same trend.

Pharmacologist Myriam Merarchi, founder and CEO of the Swiss fertility and biological age testing company Beyond Genomix, sees a lot of “biohackers” wanting to test their telomeres, since telomere health is tightly correlated with aging. The ones with a “suitcase” full of supplements tend to have horrible results.

“You take 50 pills a day that are interfering with every metabolic pathway of your cells,” Merarchi said. “Of course!” The interactions doctors worry about Maier with a dog on the couch Dr. Andrea Maier often recommends that patients pare down their supplement regimens. Courtesy of Andrea Maier

Longevity supplements are a booming market. Popular new products touted on TikTok and Instagram include NAD boosters (a popular antiaging supplement among the Hollywood elite), urolithin A (ostensibly boosts cellular health, improves muscle strength, and slows aging), and coenzyme Q10 (a popular antioxidant for fertility and aging).

Doctors are also seeing a lot of alpha-ketoglutarate (AKG). The compound, being studied clinically as a potential antiaging supplement, is one of the main ingredients in a new $49 “Longevity Mix” sold by tech biohacker Bryan Johnson.

Dietician Naras Lapsys, chief clinical officer at Chi Longevity, a private clinic in Singapore, says many people are piling these newer pills on top of older, popular longevity supplements. That could be resveratrol (used for heart health) or spermidine (touted as being good for rejuvenating cells).

“If you’re taking a longevity supplement, there’s no evidence to suggest at all taking one is good and therefore two is even better and three is even better again,” Lapsys said. “A good starting point is to strip down to a lesser number and start measuring.”

Someone who’s dehydrated regularly might want to think twice before taking a supplement like NMN, which can build up in the kidneys and cause inflammation. CoQ10 can make blood thinners less effective, and resveratrol might help hormonal cancers like breast cancer thrive and proliferate.

“If you are just taking supplements because a book has told you or an influencer has told you, if we think about levels of evidence, that sits pretty low,” Lapsys said. “Test, don’t guess.” Experts recommend a personalized, data-driven approach

All of this is deeply personal. One patient might benefit from getting more calcium, while another could benefit from ditching their B vitamins.

“I understand that not everybody can get a doctor,” Bischof said. “We’re trying to say, just educate yourself on what could be the side effect and how — a little bit — to track it.”

For patients who are excited about longevity supplements, Bischof recommends cycling them, taking one for a few months, and then pausing instead of taking them continuously throughout the year.

When you are taking a new kind of longevity supplement, you should keep tabs on how it is affecting your health in specific ways. Is your VO2 max improving? Do you have fewer colds during flu season than you used to? These are the kinds of simple check-ins that can help determine if a supplement is doing something for you.

“Have at least one marker that you can follow, an objective marker, to make sure that it’s actually helping you,” Bischof said. “Do not take something where you think it might help. You need to have an objective measure that will confirm that it works for you at this dose, at this frequency, at this age, in your current situation.”