A new study published Tuesday in the journal Science Signaling found that mice with melanoma who drank a specific kind of tasty sugar water reduced the spread of their cancer by 50-60%.

The sugar, called ‘fucose,’ (that’s pronounced fyook-ose) is found in seaweed and brewer’s yeast. In mice, it seems to be working in tandem with proteins in the body to help stop skin cancer from spreading and block tumor growth. Fucose conducts a kind of syrupy, sugary magic on fast-spreading cancer: When mice drank it in their water, the solution made their cancer cells stick in place. The result? Metastasis (cancer spread) slowed, preventing the melanoma from moving into mice lungs.

The news comes as the feds prepare the finishing touches on their first changes to how sugar is labeled on nutrition facts in five years. Proposed changes, set to be released this month, could require companies to spell out just how much added sugar and what %DV (daily value) of a consumer’s daily sugar dose is in packaged foods (a can of Coke, for example, serves up 120% of an adult’s recommended sugar for a day).

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What’s happening with the fucose in the mice is different from what happens when we digest those more standard table sugars like glucose and fructose. The sweeter sugars, found in treats like sugar cane, fruit, and corn syrup actually tend to fuel cancer growth.

Fucose is not as saccharine (or as popular) as “Big Sugar,” the sweets with their own lobbying platforms on Capitol Hill. (Interestingly, Chinese medicine has relied on fucose-rich seaweeds to treat cancer for centuries.)

But “don’t go out and start drinking seaweed smoothies thinking that you’re going to stop your cancer,” cautions Eric Lau, a researcher at Moffitt Cancer Center who co-authored the study while at Sanford Burnham Prebys Medical Discovery Institute.

The sugar will need further study, both animal and human trials, before patients can sip their fucose water cancer treatment through a straw. Today, melanoma patients are often treated with a combination of radiation, medications, and chemotherapy. The National Cancer Institute estimates about 9,940 people will die from melanoma in the U.S. this year.

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Update (7:20 pm ET) This story has been updated to clarify Eric Lau’s workplace affiliation while performing the sugar study.