You grab a Red Bull to push through your 3 p.m. brain fog. Or maybe it’s a Celsius before the gym. But according to a new study, the thing giving you “energy” might also be giving cancer cells a growth boost.

Researchers at the University of Rochester have discovered that taurine—an amino acid added to most energy drinks—is being used as a fuel source by leukemia cells. The study, published in Nature, showed that taurine actually helps cancer cells survive, divide, and spread. Which means while you’re sipping it for a productivity hit, leukemia might be getting one, too.

The researchers noted, in classic science-speak, that we should “carefully consider the risks and benefits” of taurine. Which is a polite way of saying: this stuff might be supercharging cancer and maybe we should talk about that.

This Energy Drink Ingredient May Be Fueling Cancer

Taurine isn’t new or exotic—it’s found in protein-heavy foods like meat and fish, and your body produces it naturally. But in energy drinks, it’s added in concentrated doses, marketed as a metabolism booster and focus enhancer. It’s also used in some cancer treatments to help ease chemo side effects. Ironically, that extra taurine may be doing more harm than good.

In the study, scientists implanted human leukemia cells into mice, then tracked how those cells interacted with taurine. Turns out, healthy bone marrow cells naturally produce taurine, which is then carried directly into leukemia cells via a gene called SLC6A6. Once inside, the taurine kicks off glycolysis—a cellular process that turns sugar into energy—and helps the cancer cells grow faster.

Researchers found that when taurine was blocked, the cancer didn’t grow as fast. That opens the door to a new kind of treatment—one that focuses on starving the disease instead of just attacking it.

And it might not stop with blood cancer. The team is also looking into whether taurine could be playing a similar role in other cancers like colorectal.