Yerba Mate Side Effects: An Honest Look

Because yerba mate is a caffeinated drink, the most common side effects are the familiar ones of too much caffeine. Drink more than your body is used to and you may feel jittery or anxious, notice a faster heartbeat, or have trouble falling asleep if you drank it late. None of this is unique to mate — it's what coffee, tea, or an energy drink would do at the same caffeine dose.

The practical takeaway is to treat mate's caffeine the way you'd treat coffee's: know roughly how much you're getting, watch the timing, and stop before you hit your personal limit. A long gourd session and a canned mate both deliver meaningful caffeine, so they count toward your daily total alongside everything else.

The one side-effect topic that's genuinely specific to mate is heat, and it's important to state it accurately. The IARC classifies drinking very hot beverages — above about 65°C (149°F) — as probably carcinogenic to humans (Group 2A). Crucially, that finding is about the temperature of any hot drink, not about yerba mate as a plant.

Mate comes up in this research because of how it's traditionally consumed: piping hot, through a metal bombilla, which delivers scalding liquid directly to the mouth and throat. So the documented caution isn't "yerba mate causes cancer" — it's "drinking anything scalding hot is a risk, and people have historically drunk mate scalding hot."

Some people get an upset or acidic stomach from yerba mate, and the usual culprit is caffeine on an empty stomach. Like coffee, a strong mate first thing in the morning before you've eaten can feel harsh on the gut.

If that's you, the easy adjustments are to drink mate with or after food, choose a milder con-palo leaf, use slightly cooler water, and don't push the session too long or too strong. And as with any caffeine, drinking it late in the day is the most common cause of disrupted sleep — keep mate to earlier hours if you're sensitive.

Moderation makes mate a normal drink for most healthy adults, but some people should be more cautious — mostly because of the caffeine.

Pregnant and breastfeeding people are generally advised to keep caffeine well below the typical adult guidance, so mate should be limited accordingly. Caffeine-sensitive people, anyone with a heart condition or high blood pressure, and people prone to anxiety or insomnia may want less or none. And if you take medications, caffeine can interact with some of them. The blanket rule: if a health condition or medication is in the picture, ask your doctor what's right for you. General caffeine guidance is up to about 400mg a day for healthy adults — a population average, not a personal prescription. This is not medical advice.

Drunk in moderation and not scalding hot, yerba mate is a normal caffeinated beverage for most healthy adults. The side effects worth knowing are caffeine's familiar ones if you overdo it, plus the well-documented advice to let any very hot drink cool before drinking.

So the two habits that cover almost everything: keep your total caffeine sensible across the day, and drink your mate warm rather than scalding. Do those and you've addressed the side effects that the evidence actually points to — without buying into either fear-mongering or the overblown "miracle drink" claims.