Sweetener Bitterness

Your result, the one DNA position behind it, and what the research says.

5/10 confidence.

About Sweetener Bitterness

Most non-sugar sweeteners are not purely sweet: saccharin, acesulfame K and the steviol glycosides in stevia carry a bitter or metallic edge that some people notice strongly and others barely at all. That difference is partly down to bitter receptors, which sweeteners activate as a side effect of their shape. TAS2R9 is one of the receptors involved, and this change swaps an amino acid in it.

Good to know: Most non-sugar sweeteners activate bitter receptors as a side effect of their shape. Different sweeteners hit different receptors, so this does not apply to all of them. This is a third bitter receptor, separate from the two other bitter cards on the site.

Fun fact: Saccharin was discovered in 1879 by a chemist who did not wash his hands before dinner and noticed his bread tasted sweet.

Discovery: Two bitter receptors were shown to respond to saccharin and acesulfame K in 2004, and this position in TAS2R9 was tied to acesulfame K bitterness in 2013.

The Variant

The single variant behind this trait

Gene: TAS2R9

Variant (rsID): rs3741845

Location: Chr 12:10,809,516

dbSNP rs3741845

The studies

Bitterness of the non-nutritive sweetener acesulfame potassium varies with polymorphisms in TAS2R9 and TAS2R31 (Allen AL et al., Chemical senses, 2013)

Other lifestyle traits

Salt Taste: A change in the tail of the TRPV1 gene, studied alongside salt taste perception and how much salt people add.

Sense of Smell: A change next to APOE, linked in an older-adult study to how well people identify smells.

Asparagus Odor Detection: A marker in a cluster of smell-receptor genes that is linked to how readily you notice the distinctive smell asparagus gives urine.

Back to All Traits

Content updated September 2026.

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