Quick & curious · Physics

Bananas are slightly radioactive.

Hanging banana bunches at a market stall
Photo: Alpha from Melbourne, Australia · CC BY-SA 2.0 · Original

0.1µSvper banana

The story behind it

Bananas are a tiny bit radioactive.

Natural potassium-40 is to blame. One banana is about 0.1 microsieverts; a chest CT about 70,000 bananas. And because the body excretes excess potassium, it doesn't add up.

Sources

Every statement in this discovery is backed by one of these sources and was checked before publication.

  1. Wikipedia: Banana equivalent dose (accessed 2026-10-05)

Image credits

  • “Bananas by the bunch - Carrara Market (2569636765).jpg”, Alpha from Melbourne, Australia, CC BY-SA 2.0