Maybe — the honest answer is that nobody knows the exact number. A 2014 Rockefeller University study estimated that humans can discriminate more than one trillion olfactory stimuli, but a published critique argued that figure depends heavily on the mathematical model used to calculate it. What both sides support is that human smell is far more powerful than the old claim of about 10,000 odors.
The Rockefeller team did not test a trillion smells one by one — nobody could. Instead, volunteers sniffed vials containing mixtures drawn from a set of 128 scent molecules, and the researchers measured how different two mixtures had to be before people could reliably tell them apart. From that threshold, they extrapolated across all the possible mixtures those molecules could form, and the math landed above one trillion distinguishable combinations.
It was a clever design, and it made headlines because it suggested smell had been badly underestimated compared with vision and hearing.
The critique that followed did not dispute that people performed well in the tests. It disputed the leap from the tests to the headline number. Gerkin and Castro showed that the same experimental data, run through different but reasonable assumptions about how the discrimination threshold behaves, could produce dramatically different totals — far lower, or even higher. In other words, the trillion is less a direct measurement than the output of a model, and the model does much of the work.
That does not rescue the old 10,000 figure, which traced back to a rough estimate from the 1920s rather than solid testing. The defensible conclusion is the middle one: your nose discriminates vastly more scents than the textbooks used to claim, and pinning down the real number will take better methods than either side has so far.
See the 20-second version: "Can You Really Smell a Trillion Scents? — Things You Didn't Know" on LOE PRESSURE (TikTok @loepressure and YouTube @LoePressure).
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Sources: Bushdid et al. (2014), Science — Rockefeller University study on human olfactory discrimination; Gerkin & Castro (2015), eLife — critique of the trillion-stimuli estimate.