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Caffeine blocks this receptor. Affects sensitivity.
iHow to read this: each row is one possible genotype, the two DNA letters you carry at this position, one inherited from each parent. "Normal" matches the more common version; "Carrier" (heterozygous) means you have one copy of each version, usually a partial effect; "Variant" (homozygous) means both copies carry the less common version, usually the strongest effect. The estimated frequency below is calculated from the variant's frequency in the general population (Hardy-Weinberg principle) — it is a population estimate, not a measurement of our own customers.
| Genotype | Impact | Est. frequency | What it means |
|---|---|---|---|
| TTNormal | Moderate | ~30% | T/T: high caffeine sensitivity. Anxiety, jitters and sleep disturbance appear at doses others tolerate; some studies also find the largest performance boost from small doses in this genotype. Keep pre-workout caffeine low and early. |
| TCCarrier | Low impact | ~50% | T/C: intermediate caffeine sensitivity. |
| CCVariant | Normal | ~20% | C/C: low caffeine sensitivity; typical tolerance to moderate doses. |
Estimated with the Hardy-Weinberg principle from the variant's population frequency, not measured directly.
How to get and read your raw DNA file
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