Commonly-used herbal and dietary supplements taken by millions of Americans to stay healthy have been tied to a rising number of cases of liver damage and toxicity.

Supplement-related liver failure that required U.S. patients to be put on a waitlist for a transplant increased by eight times the previous level from 1995 through 2020, according to a 2022 study in the journal Liver Transplantation. Another study found that 20 percent of liver toxicity cases around the country are linked to the supplements, according to research published in the journal Hepatology.

The result of the damage can be life-threatening. Liver disease results in more than 50,000 deaths each year, according to federal health officials. The result of the drug-induced liver injury known as hepatotoxicity can be impaired liver function and liver failure. Cases of hepatotoxicity may be rare, but it remains unclear just how rare.

Still, some 15 million Americans are using supplements containing ingredients that are potentially harmful to the liver.

“I think people assume these things are safe,” Dr. Dina Halegoua-De Marzio, a Jefferson Health hepatologist, told NBC News. “The No. 1 reason we see people taking these are for good health or to supplement their health, and so I don’t think that they realize that there is a real risk here.”

So, what are the offending supplements tied to these cases? You may regularly use them in cooking. Many patients take them with the aim of improving their health. The bright yellow spice turmeric is the most commonly consumed in the U.S., according to a study published last year in the journal JAMA Network Open. Black cohosh, red yeast rice, Garcinia cambogia, and green tea extract were also identified on a list compiled by researchers at the University of Michigan.

“When you cook with turmeric, that could be really safe. But some of the supplements now are 2,000 milligrams plus, which is a very high dose of turmeric,” Halegoua-De Marzio said, noting that adding black pepper could make the liver “really sick.”

Online, many of these supplements are promoted as more natural options than prescription medications. But, they are not subject to the same kind of testing and scrutiny as other drugs. That’s not the only issue. Physicians say insufficient attention in medical screenings and mislabeling are two other problems to be aware of.

“We performed analytical chemistry and found about a 50 percent mismatch between stated ingredients on the label and what they actually contained, which is quite alarming,” Dr. Robert Fontana, a University of Michigan Medicine hepatologist, said in a statement. “If you buy a supplement and it says it has a certain ingredient, it’s basically a coin flip if that’s true or not.”

Fewer than 40 percent of patients willingly tell their doctors about the supplements they are taking, according to Kaiser Permanente primary care physician Dr. Crystal Xue.

Without the guiding hand of doctors, people who take too much may not realize the risk. New Jersey’s Robert Grafton told NBC News that if he hadn’t been in the medical field, he might have taken more supplements to help him feel better. Instead, following a trip to the hospital, he found out he had a drug-induced liver injury after taking ashwagandha, turmeric pills, and other supplements.

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Some people are even genetically vulnerable to this kind of damage. Although, that’s also true for prescription drugs.

Symptoms of liver damage and toxicity can differ, but generally include fever, fatigue, abdominal pain, nausea and vomiting, urine changes, and jaundice.

There are some 44,000 estimated cases of liver damage associated with the drugs each year, including 2,700 deaths. That number is likely an undercount.

People can still take supplements, given they do so safely. However, given the lack of regulation in this area, researchers hope to raise awareness about the issue to try to prevent future deaths.

“We’re not trying to create alarm,” Fontana said.

“We’re just trying to increase awareness that the over-the-counter supplements people are taking and buying have not been tested nor necessarily proven to be safe,” he said.

Your mom thinks it’s steroids, your gym bros think it’s a magic powder that gets you jacked overnight: Unfortunately, the best creatine supplements are decidedly neither of those things. That being said, creatine is one of the most thoroughly studied supplements on the market—a veritable beacon of hope in an otherwise largely unregulated industry—that actually does help boost strength, athletic performance, and muscle mass to a small (but not insignificant!) degree. “I recommend [creatine] to anyone who wants to improve strength, power, and lean muscle mass growth,” Mike Dewar, strength coach and founder of J2FIT, says. “Some newer studies show that creatine can also improve brain health.”

I’ve personally been taking five grams of creatine every day for years, and pretty much every serious gym rat I know swears by the stuff. (Of course, you should consult with your healthcare provider before taking any dietary supplement.) Will creatine magically make you a vascular, engorged freakbeast overnight? No. Will it—when coupled with hard training and good recovery—help with your gains? For sure. If you’re not sure where to start, check out our top picks for the best creatine supplements below.

The Best Creatine Supplements, at a Glance:

Best Creatine Overall: Nutricost Creatine Monohydrate Powder

If you’ve read anything I’ve written about protein powder or supplements, you know that I’ve got a soft spot for Nutricost. The value here is really solid, and if you’re just looking for a big tub of creatine monohydrate—the only kind of creatine you should be buying, by the way—you can’t go wrong with Nutricost. (It also has the standard dose of five grams per scoop, which is key.) I’m partial to the unflavored version, since I don’t really mind the taste, but the brand offers a bunch of different options, ranging from Blue Raspberry to Mandarin Orange. If you’re looking for something to whack into a protein shake or slug down with some water, this is your best bet.

Best Pre-Workout With Creatine: Gorilla Mind Gorilla Mode Pre-Workout

It’s easy to get bogged down in the supplement aisle—I myself am certainly guilty of having a few cabinets in my kitchen that look more like a GNC than I’d care to admit. For those trying to streamline their supplementation regimen, taking a pre-workout that has your daily dose of creatine built into the formula is a great way to get two birds stoned at once. With a grip of decent flavors and both stim and stim-free options, this is a solid choice for gym rats everywhere. (This also happens to be our top pick for the best pre-workout for resistance training on the market.) One thing to note, though: Creatine only works if you take it every day, so on rest days, it’s best to use a regular creatine supplement instead.

Best Creatine Pills: BulkSupplements Creatine Monohydrate Capsules

Don’t mess with powders and potions? We feel you. For on-the-go meatheaderry, I like to pack these creatine pills instead of making a mess trying to funnel a bunch of powder into, say, an airport water bottle using a rolled-up magazine. (Though if you’re going to go that route, make sure you use an issue of GQ.) A word of warning, though: The serving size for these is seven pills, which is (obviously) a lot of pills. It never bothers me, but it’s good to keep in mind.

Best Creatine Gummies: Legion Creatine Monohydrate Gummies

More of a Flintstones vitamin dude? You’re in luck: Legion makes some delicious creatine gummies that are truly a joy to eat. Is hammering five gummies the most efficient way to get your creatine in? Probably not—but it make every morning a little more fun, which is always worth it in our book.

Best Creatine for Traveling: Nutricost Creatine Monohydrate Powder Variety Stickpacks

For on-the-go supplementation, it’s tough to beat these little stick packs of creatine from Nutricost—especially if you’re not a fan of knocking back a handful of horse pills. They come in a ton of great flavors, and contain your tried-and-true five grams of creatine monohydrate in each stick. They’re not as cheap as bulk powder, but you’re paying for convenience.

Best Creatine Tablets: Animal Creatine Chews Tablets

While these chewable creatine tablets from Animal are marginally less fun than the gummies we listed above, they’re marginally more fun than an unflavored powder or a handful of gel-caps. Animal is an OG in the supplement game, and if you’ve been in the iron game for a while, you might remember their old school black-and-white print ads or the Animal Cage at the Arnold.

More Creatine Supplements We Love

What to Look for in Creatine Supplements

Dose: For most people, five grams (often listed as 5,000mg on nutrition labels to… make it seem like more?) is going to be the sweet spot. There’s anecdotal evidence that bigger guys see bigger gains with bigger doses of creatine—and some studies suggest doses up to 20 grams a day help with cognitive function—but five grams is where it’s at, IMO. Plus, going above five grams is tough on the ol’ stomach, anecdotally.

Type: Stick with creatine monohydrate. This is the gold standard and the most researched kind of creatine on the market with no additives. Every other type of creatine is pretty much just marketing.

Creatine FAQ

How We Tested

In my 15 years of strength training, I’ve taken a ton of creatine, from no-name Wal-Mart brands to high-end, probably-too-expensive tubs from the newest, most hyped-up DTC brands in the game. Plus, I also consulted with my network of meatheads testers, which includes my fellow gym rats office, former NCAA athletes, NASM– and ACE-certified trainers, and competitive BJJ grapplers.

Meet the Expert

Mike Dewar is the founder and strength coach at J2FIT. With 13+ years of experience as a personal trainer, five years as a NCAA Strength Coach at New York University, and over 550+ published fitness and nutrition articles, he knows a thing or two about fitness. He also holds a masters in Exercise Physiology from Columbia University and a bachelors in Exercise Science from Bowling Green State University in Ohio. You can check him out on Instagram and YouTube.

Ultraviolet (UV) emission plays a vital role in applications such as sterilization, anti-counterfeiting, phototherapy, forensic analysis, and communication. To meet these demands, researchers have developed various UV-emitting materials, including colloidal quantum dots, small molecules, and polymers. However, many of these materials rely on toxic metals like cadmium (Cd) or lead (Pb), critical raw materials, or non-renewable petroleum-based chemicals. Additionally, their synthesis often involves complex and expensive processes, raising significant environmental concerns.

A team of materials scientists, led by Associate Professor Jia Wang from Umeå University in Sweden, in collaboration with Professor Ludvig Edman and colleagues, recently introduced a sustainable alternative. They synthesized carbon dots (CDs) with efficient UV emission, derived from a renewable and abundant biomass feedstock—green tea extract.

This peer-reviewed article was published in Nano Research in April 2025.

“In this study, we convert a common green tea extract into UV-emitting CDs through a simple hydrothermal process,” explained Jia Wang, the corresponding authors. Wang is also a research PI with the Wallenberg Initiative Materials Science for Sustainability. “These CDs exhibit a photoluminescence peak at 384 nm with a quantum yield (PLQY) of 17% in water. Interestingly, when dissolved in ‘poor’ solvents, their emission becomes blue-shifted and nearly five times stronger.”

CDs are metal-free, quasi-zero-dimensional nanostructures typically smaller than 10 nm. These nanoparticles can achieve optical performances comparable to inorganic quantum dots while being environmentally friendly. Because CDs can be synthesized from various carbon-rich sources, they hold great potential as a sustainable alternative.

The team highlighted the progress being made in biomass-derived CDs, which have been gaining attention for their environmental benefits. “Biomass sources like food waste, forest and agricultural residues, and even household waste have been used to produce CDs, demonstrating efficient emission in both the visible and near-infrared regions. However, successful UV emission from CDs has been rare,” Jia Wang noted.

In this study, the UV emission of CDs exhibited clear solvent dependence. As the solvent polarity index increased, the PLQY decreased, with the highest PLQY of 81% achieved using the highly hydrophobic solvent 3-phenoxyanisole. Wang’s team attributed this enhancement to aggregation-induced emission. “These CDs are about 3.5 nm on average,” Wang explained. “In poor solvents, they form larger aggregates (10–30 nm) due to reduced dispersibility. This aggregation creates more compact molecular structures and rigid scaffolds, which limits non-radiative recombination and significantly enhances PLQY.”

The team also explored the synthesis of CDs from green tea bag powder instead of green tea extract. However, the resulting CDs only emitted blue light, not UV. “Even simple pretreatment steps like extraction or isolation can decisively influence the structure and properties of the final CDs,” Wang said. “Rational design of these pretreatments is an important action for advancing biomass-derived functional materials.”

Beyond their optical properties, the team is also eager to explore additional applications. “Our preliminary results suggest that these CDs can strongly inhibit the proliferation of SH-SY5Y neuroblastoma cells,” said Wang. “Our collaborators are conducting more detailed studies on their antioxidative properties.

The first author of the study is Dr. Henry Opoku. Other contributors include Dr. Junkai Ren, Dr. Xin Zhou, and Dr. Shi Tang from Umeå University, Sweden; Peijuan Zhang and Prof. Dongfeng Dang from the School of Chemistry at Xi’an Jiaotong University, China.​

This work was supported by generous funding from J. C. Kempes Minnes Stipendiefond (SMK-21-0015 and SMK-1956), the Swedish Research Council (2019-02345, 2020-04437, and 2021-04778), Bertil & Britt Svenssons stiftelse för belysningsteknik (2021 höst-14 and 2022 höst-31), the Knut and Alice Wallenberg Foundation for a Proof of Concept grant (KAW 2022.0381), the Wallenberg Initiative Materials Science for Sustainability (WISE) funded by the Knut and Alice Wallenberg Foundation (WISE-AP01-D02), and the European Union through an ERC Advanced Grant (ERC, InnovaLEC, 101096650).

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 17 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2023 InCites Journal Citation Reports, its 2023 IF is 9.6 (9.0, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.