Good News on Tea: Few Contaminants, Lots of Health Benefits - Consumer Reports (2025)

Tea has long been synonymous with good health, and for good reason. True teas—brews made from leaves of Camellia sinensis, aka the tea plant—are packed with antioxidants, which are potent disease-fighting compounds. No wonder studies show that regular tea drinkers may have lower risks of heart attack, type 2 diabetes, cancer, and cognitive decline.

And herbal teas—infusions steeped with herbs, flowers, and spices—may have health benefits of their own and, if nothing else, can be a great no-calorie way to keep yourself hydrated.

But some research has also suggested that teas can be contaminated with potentially harmful chemicals. That includes residues of pesticides sprayed on the plants when they are in the field, lead or other heavy metals absorbed by the plants when they are growing, and plasticizer chemicals like phthalates that may get into the brews from tea bags or other sources, says Eric Boring, PhD, a food safety scientist at Consumer Reports.

Boring, at CR, says that the amounts of lead we found in those two products were not high enough to pose an immediate health threat but could be a concern if regularly consumed, especially if you have other exposures from your diet or the environment. “So for those teas, I would recommend limiting yourself to one cup a day,” he says.

He also says that while CR’s tests covered a broad cross-section of themarketplace, “there are obviously many teas we did not look at, and some contaminants we didn’t measure.” He says that CR’s tests “overall, suggest that people can drink tea without much concern about many key contaminants.”

Still, that may leave you wondering whether some kinds of tea are better for you than others and what, exactly, the health benefits of tea are anyway. Here’s what you need to know.

How Tea Affects Health

Teas made from the tea plant come in four basic varieties: black, oolong, green, and white. They differ in flavor and color depending on how the leaves of the plant are picked, rolled, crushed, and exposed to air before drying.

For example, black teas are exposed to the air for an extended period before being steamed and dried, which promotes oxidation and gives the tea its dark color and deep flavor. Oolong teas are exposed for a shorter time, creating a slightly milder color and flavor. The leaves in green tea retain their color because they’re steamed and dried soon after picking, preventing most oxidation, so green tea has a grassier, more herbal flavor. White teas are even lighter in color and flavor because they’re made from young tea buds that are steamed and dried immediately after picking.

In addition to the obvious differences in color and flavor, there are some differences in health effects. Most notably, the darker the tea, the higher the caffeine level tends to be. An 8-ounce cup of black tea, for example, usually has about 40 to 60 milligrams of caffeine, about half of what’s in a typical cup of brewed coffee and about twice as much as what’s in green tea.

While caffeine can promote alertness, too much can make you jittery and possibly pose other health risks. That’s why the Food and Drug Administration recommends consuming no more than 400 mg of it per day. If you are watching your caffeine intake, then, you may want to drink more green tea, for example, than black. Note, though, that how much caffeine ends up in a cup of tea can vary from product to product, and also depends on how long you let it steep. So monitor how you feel after drinking your tea and adjust accordingly.

There are also some subtle differences among tea types in the amounts of antioxidants—a broad class of substances that offer a multitude of health benefits—they contain. But overall, they are all excellent sources of those beneficial compounds, says Michelle Francl, PhD, professor of chemistry at Bryn Mawr College in Pa., who’s also the author of the book “Steeped: The Chemistry of Tea” (Royal Society of Chemistry, 2024). “Even though we tend to think of green tea as kind of healthier than black tea, the [antioxidant] profiles are practically all the same,” she says.

Here’s a quick rundown of tea’s likely health benefits and the compounds thought to contribute to them.

Heart Disease

Diabetes

Weight Loss

Bone Health

Cancer

Cognitive Decline

What About Herbal Teas?

Peppermint, chamomile, eucalyptus, echinacea, ginger, slippery elm—those are just a few of the hundreds of herbal teas you can buy, alone or in combination. They often have purported health benefits, from helping to soothe a sore throat, improving sleep, and relieving menstrual pain to easing stress, boosting immunity, and aiding digestion. But in part because there are so many of them, with so many different potential health claims, it can be hard to document their benefits with hard, scientific research.

That said, herbal teas often contain some of the same antioxidants and other healthful compounds found in true teas. Many of them also have long histories of use as traditional medicines from around the world, with few known risks when consumed in typical formulations. And, of course, they can be no-calorie ways to keep yourself hydrated—and many people find relief, or just comfort, from a soothing cup of hot herbal tea.

How to Make a Healthy Cup of Tea

Advice on making the perfect cup of tea focuses mostly on taste. While that varies in part depending on your preferences, there are a few general tips. Black tea, for instance, can be made with water just after it reaches the boiling point, while green teas need a little more delicate treatment, with water that’s not as hot, roughly 175° F.

But there are also a few things to consider in terms of maximizing tea’s health benefits.

For example, people who like to add a splash of milk to their black or oolong tea may want to reconsider the habit, at least occasionally. Protein in milk may bind with some of the compounds in black tea, reducing your body’s ability to absorb them, researchers say.

And while adding milk or cream to your tea may be delicious, it also adds fat and calories. Similarly, sweeteners like sugar and honey—especially in the amounts you’d find in chai or bubble teas—may undermine some of tea’s health benefits.

On the other hand, squeezing some lemon juice may be a good idea. According to research from Purdue University, that could help some of the beneficial chemicals in the drink survive digestion.