It reduces your risk of heart disease and stroke, protects brain cells and improves brain health, improves muscle mass, boosts your metabolism, and helps lower your risk of certain types of cancer. Take a cursory glance at green tea’s health benefits, and it’s easy to think you should be getting it pumped through an IV every morning. But alas, nothing’s perfect — green tea included. Can it actually be bad for you though?

Well, how good it is for you can certainly vary. When it comes to all the good stuff in green tea — active compounds EGCG and other catechins — how much you actually get can depend on the brand and variety. A Consumer Lab study found that bottled green teas contain anywhere from 4 mg to 47 mg of EGCG (epigallocatechin-3-gallate) per cup. Brewable green tea (from tea bags, loose tea, or a K-Cup) ranged from 25 to 86 mg of EGCG per serving. Matcha tea varieties ranged from 17 mg to 109 mg of EGCG per serving. Translation: brew your own — chances are that the average bottled brew from your supermarket’s fridge won’t cut it. But heads up, all that EGCG isn’t great for everyone. Avoid green tea completely if you’re pregnant, since EGCG can mess with the way folate works in the body and can pose risks like low birth weight and premature birth.

A surprising ingredient you probably didn’t expect in your cup? Lead. Don’t panic yet — yes, the study also found lead in some of the green teas, but it’s not necessarily cause for concern. Some, like Teavana varieties, found none, while others, like Lipton and Bigelow, were found to contain 1.25 to 2.5 micrograms of lead per serving. Sounds scary, but it’s not unique to green tea — any plant can take lead up from the ground into its leaves. But Dr. Tod Cooperman, president of ConsumerLab.com, does tell the New York Times, “The green tea plant is known to absorb lead at a higher rate than other plants from the environment, and lead also can build up on the surface of the leaves.”

So why does the amount vary so much? It depends on where the tea leaves originated — China, for one, is likely to have more lead because of pollution. If you’re drinking decaf, your cup will also have less lead, since the process of decaffeinating also removes lead. Whatever you’re drinking, though, Cooperman assures the New York Times that the lead won’t cause health issues. “The majority of the lead is staying with the leaf,” he tells them. “If you’re brewing it with a tea bag, the tea bag is very effectively filtering out most of the lead by keeping those tea leaves inside the bag. So it’s fine as long as you’re not eating the leaves.”

The thing that may actually pose a risk is caffeine content. If you’re generally sensitive to caffeine or have a sensitive stomach, pace yourself — it can lead to heart palpitations, restlessness, and sleep problems. Check with your doc if you take stimulant medication with amphetamines too — since those speed up the nervous system and increase heart rate, and adding green tea on top of them can cause serious heart rate and blood pressure issues. Other common medications that may have interactions with caffeine are birth control pills, MAOIs for depression, and some antibiotics, so if you’re drinking a lot of the stuff, let your doctor know at your next checkup.

Bottom line: If you’re generally healthy and drinking a couple cups a day of brewed green tea and not combining it with other caffeine or stimulants, chances are that the benefits outweigh the risks. But, as with everything else, you can have too much of a good thing — so, best to skip that green tea IV after all.

Diana Vilibert is a freelance writer and copywriter living in Brooklyn, NY. She loves flea markets, martinis, to-do lists, traveling, and wearing leggings as pants. You can see more of her writing at www.dianavilibert.com and follow her on Twitter at @dianavilibert.