The Best and Worst Smells in the World, According to Science

The best smell in the world, according to the biggest cross-cultural study so far, is vanilla. The worst, among everyday smells, is isovaleric acid, the main smell of sweaty feet. Beyond the lab, the list of contenders includes cut grass, rain, the sea, rotten eggs, durian and a chemical so foul it once evacuated part of a German city.

What Does Science Say Is the Best Smell?

In a 2022 study in Current Biology, researchers asked people from nine very different communities, from hunter-gatherers to city dwellers, to rank the same set of smells. Karolinska Institutet’s summary gives the result: vanilla came first, ethyl butyrate (a fruity, peach-like smell) second, and isovaleric acid last.

The striking part is that culture explained surprisingly little. Personal taste mattered more than where people grew up, and the molecule itself mattered too. A 2024 follow-up with 582 people found similar cross-cultural overlap, while stressing that experience still shapes preference. So vanilla isn’t loved everywhere by accident, and it isn’t loved by everyone either.

The Best Smells

Vanilla. The winner. Its main molecule, vanillin, is warm, sweet and creamy, and it’s one of the most used materials in perfume for exactly that reason. Our vanilla perfumes show how many ways it can go.

Freshly cut grass. That green smell is mostly cis-3-hexenal and its relatives, the “green leaf volatiles” a plant releases when it’s damaged. It’s a distress signal from the lawn, and most of us find it lovely.

Rain on dry ground. Petrichor comes partly from oils that plants release in dry weather, which collect on rocks and soil, and partly from geosmin, an earthy molecule made by soil bacteria. Our noses are extraordinarily sensitive to geosmin, which is why you can smell rain coming. Rain perfumes try to bottle it.

Baking bread and coffee. Both owe their smell to the Maillard reaction, the browning chemistry between sugars and amino acids that also gives toast and roasted meat their smell. Coffee alone has hundreds of aroma compounds. Our coffee perfumes go further.

The sea. Sea air’s smell comes largely from dimethyl sulfide, made by plankton. On its own it smells of boiled cabbage. Diluted in the wind off the ocean, it smells like a holiday.

The Worst Smells

Sweaty feet. Isovaleric acid, the bottom-ranked smell in the 2022 study, is made by skin bacteria breaking down sweat. It also turns up in some cheeses, which is why a strong cheese can smell alarmingly like socks.

Rotten eggs. Hydrogen sulfide, the smell of hot springs, swamps and drains. It’s toxic at high concentrations, and at very high levels it deadens the sense of smell, which makes it more dangerous.

Durian. The Southeast Asian “king of fruits” divides people completely: sweet and custardy to some, sewage and rotten onion to others. Its sulfur compounds are the problem, and it’s banned on Singapore’s public transport.

The corpse flower. Titan arum smells of rotting flesh to attract the beetles and flies that pollinate it. Kew’s scientists found sulfur compounds behind the stench, and found that its relatives in the same genus smell of fruit, anise and even chocolate instead. The worst of the smell comes on a single evening.

Thioacetone. Possibly the worst smell ever made. In 1889, an attempt to make it in the German city of Freiburg released a smell that caused vomiting and fainting over a wide area of the city, and the work was abandoned. Chemist Derek Lowe describes it as one of the compounds he won’t work with.

What Does This Mean for Choosing a Perfume?

That shared favourites are a good starting point, and your own nose is the final word. Vanilla and fruity notes top the charts for a reason, which is why they’re everywhere in perfume. But if you hate sweet scents, you’re not wrong, just in the minority. Start with the everyday smell you love, work out which part of it you love (the roast in coffee or the milk? the wet earth in rain or the cool air?), and look for that in a note list. The fragrance wheel guide and the notes guide help put it into words.