TAS2R38: The Bitter-Taste Gene Behind Your Broccoli Feud
The gene that decides whether kale tastes green or like soap.
TAS2R38 is the gene behind one of the oldest party tricks in genetics: whether a strip of PTC paper tastes like nothing or like the back of a soap bottle. The receptor it builds sits on your tongue and reacts to a family of bitter compounds. The same compounds, or close cousins, show up naturally in broccoli, kale, Brussels sprouts, and the rest of the cabbage family. So your version of this receptor has a real say in how bitter your greens taste to you, and not to the person sitting next to you. The variant we report here is rs713598. It changes one amino acid in the receptor at position 49. One version of the receptor grabs those bitter molecules tightly and fires hard. The other version is sluggish about it. If you got the sensitive build from both parents, raw kale can taste genuinely punishing. If you got the quiet build, the same kale reads as mild and green. Most people land somewhere in between with one copy of each. Here is the honest part. None of this tells you what to eat or whether you have a health problem. It explains a preference. A lot of people who "hate vegetables" are not being difficult; they are tasting a bitterness that the rest of us mostly cannot. Knowing that is useful, because the fix is about preparation, not willpower.
What TAS2R38 does
Builds a bitter-taste receptor (TAS2R38) on the surface of your taste cells.
Reacts to PTC and PROP, two lab compounds chemists use to measure bitter sensitivity, plus the glucosinolate compounds found naturally in cruciferous vegetables.
Sets how intensely you register the bitterness in broccoli, kale, Brussels sprouts, cabbage, and similar greens.
Influences taste preferences for other bitter or strong-flavored items too, like black coffee, dark beer, and tonic water.
Comes in a sensitive build and a quiet build; rs713598 is one of the spots that decides which you carry.
Your variants, decoded
This single letter change swaps one amino acid in the bitter-taste receptor at position 49. In the orientation we use here, the C version builds the sensitive (proline) receptor and the G version builds the sluggish (alanine) one. It travels with two nearby variants as a package, but this site does a lot of the work on its own. One caution worth knowing: this is a notoriously strand-flippable SNP. Consumer files (like 23andMe or AncestryDNA) report it with the letters C and G, but different labs read it from opposite DNA strands, so the same physical result can be printed with the taster and non-taster letters swapped relative to the rows below. Because of that, the safest way to read your result is by the taster vs non-taster interpretation your provider gives you, or a strand-aware lookup tool, rather than hand-matching the raw C/G letters from your file.
| CC | Two copies of the sensitive build. You are most likely a strong bitter taster: PTC paper tastes harsh, and raw cruciferous greens can read as genuinely bitter. In a controlled taste study, CC tongues detected the bitter compound PROP at the lowest concentrations. |
| CG | One of each. Intermediate sensitivity. Bitter greens register, but usually as background rather than a wall. Most people fall here. |
| GG | Two copies of the quiet build. You are likely a bitter non-taster: PTC paper tastes like plain paper, and the bitterness in kale or sprouts mostly slips past you. Carriers of the G version needed higher concentrations before they could detect PROP at all. |
Genotypes are shown order-insensitively and on the forward strand; your own export may print the complementary letters — the meaning is the same.
What the research suggests
If you carry the sensitive CC genotype, raw cruciferous vegetables taste markedly more bitter to you, because in a controlled taste test CC individuals detected the bitter compound PROP at lower concentrations than G-allele carriers. That's a preparation problem, not a willpower one. Cooking methods that cut perceived bitterness make the same vegetables far easier to enjoy, so the practical move is in the kitchen rather than in a capsule.
PubMed 28738701 · measured taste responsiveness by rs713598 genotype and found the CC genotype detected the bitter compound PROP at lower concentrations than G-allele carriers, with no biochemical or body-composition differences between genotypes
Educational only — not medical advice. “General evidence” means the finding is real but the supplement’s benefit isn’t unique to your genotype.
See this matched to your own DNA — free.
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Questions
Does TAS2R38 mean I'm allergic to vegetables or can't digest them?
No. It only changes how bitter certain vegetables taste to you. Your ability to digest and absorb nutrients from broccoli or kale is the same whether you taste the bitterness strongly or barely notice it. This is a flavor story, not a digestion or allergy one.
I'm a strong bitter taster. Should I just skip cruciferous vegetables?
No reason to. The bitterness is a taste experience, not a warning. If raw kale fights you, change how you cook it rather than dropping the whole food group. Roasting caramelizes the sugars, blanching pulls some bitterness into the water, and a hit of olive oil, salt, lemon, or parmesan reliably softens the edge.
Why does my 23andMe file show a different result than the one listed here?
This is one of the trickiest SNPs to read off a raw file. DNA can be read from either of two complementary strands, and consumer labs don't all pick the same one, so the C and G letters can mean the opposite of what they do on this page. The cleanest fix is to trust the taster vs non-taster label your provider reports (or use a strand-aware lookup), rather than hand-matching the raw C/G letters. The biology underneath is the same either way: the sensitive receptor is the strong taster, the sluggish one is the non-taster.
Is being a bitter taster good or bad for my health?
Neither, as far as this page is concerned. Studies have chased links between taster status and diet quality, but the findings are inconsistent and we won't make a health claim we can't stand behind. What's solid is the taste mechanism itself. Use that to eat more of the vegetables you like, prepared in a way you enjoy.