TheyaVue Side Effects and Interactions to Know

Two capsules a day give 40 mg NE of niacin. NIH's Office of Dietary Supplements sets the Tolerable Upper Intake Level for supplemental niacin at 35 mg a day, based on the flushing reaction niacin can cause National Institutes of Health, 2022. That limit applies to niacin from supplements, not niacin naturally occurring in food, so this 40 mg counts fully against it.

The panel lists the amount as "20 mg NE" per capsule and never says which chemical form it uses. That distinction matters: nicotinic acid causes the flushing reaction directly, while nicotinamide generally does not, and the fact sheet's 35 mg limit does not separate the two forms. Without knowing the form, neither you nor we can say how likely flushing is at this dose. Anyone with liver disease, gout or a peptic ulcer should raise this specific number with a doctor before starting.

Eight hundred micrograms of biotin a day is well below the doses linked to the worst lab interference, but the mechanism does not have a clean safety floor. NIH's Office of Dietary Supplements reports that a single 10 mg dose affected thyroid test results within 24 hours, that biotin has caused false diagnoses of Graves' disease at 10-300 mg/day, and describes a reported patient death linked to a falsely low troponin result National Institutes of Health, 2022.

The FDA has issued its own safety communication on this, specifically about troponin, the test used to diagnose a heart attack in the emergency room. It published a list of troponin test devices known to be affected by biotin without a workaround, after receiving reports of falsely low results, and advises lab staff to ask patients about biotin supplement use U.S. et al., 2022. The practical takeaway does not depend on the exact dose: tell any clinic drawing your blood, especially before cardiac or thyroid testing, that you take a biotin-containing supplement.

Thirty-two milligrams of zinc a day sits under the 40 mg adult Tolerable Upper Intake Level from all sources combined National Institutes of Health, 2026, but that ceiling adds up across everything in your cabinet: a multivitamin, a cold-remedy lozenge, a separate zinc supplement. Room under the limit shrinks fast once you stack products.

Zinc at 50 mg a day or more, mostly from supplements, can interfere with copper absorption and cause a copper deficiency National Institutes of Health, 2026, which is why a real eye formula pairs the two. This label's 2 mg of copper a day is an exact match for AREDS2's copper amount, so that specific safeguard is handled correctly here, even though the rest of the formula does not match the trial.

This label's vitamin A comes from beta-carotene, at a trace 50 mcg RAE a capsule (100 mcg RAE a day), equal to roughly 0.2 mg of beta-carotene. That is nowhere near the doses that raised concern: the CARET trial gave smokers and asbestos-exposed workers 30 mg/day beta-carotene plus retinyl palmitate and found 28% more lung cancer and 46% more lung cancer deaths than placebo, stopping the trial early Omenn et al., 1996; the ATBC trial found 18% more lung cancer in male smokers taking 20 mg/day beta-carotene National Institutes of Health, 2025. Both harms appeared only in smokers and former smokers, not in nonsmokers studied elsewhere, and both are why AREDS2 dropped beta-carotene for lutein and zeaxanthin.

At roughly one-hundredth of those doses, this product carries no established cancer signal on its own. If you smoke or used to, the honest caution is about stacking: mention this product to a doctor before adding any separate high-dose beta-carotene supplement on top of it.

NIH's Office of Dietary Supplements sets the adult Tolerable Upper Intake Level for vitamin E at 1,000 mg a day and warns that large supplemental doses, with one physicians' trial using 400 IU (about 180 mg) every other day for eight years, have been linked to a higher hemorrhagic stroke risk, and can raise bleeding risk further when combined with a blood thinner such as warfarin National Institutes of Health, 2021. This label supplies about 20 mg a day (roughly 44 IU) of the synthetic DL-alpha form, under a ninth of the amount used in that trial and far under the 1,000 mg UL.

The dose here is not the concern. The concern is what else might be in the blend: quercetin and grape seed extract both carry their own theoretical bleeding notes, and their amounts are not published, so anyone already on a blood thinner should mention this whole product to a doctor rather than reasoning from the vitamin E line alone.

A dedicated safety review of quercetin found mostly mild effects in short-term human studies, but flagged a lack of long-term (over 12 weeks) data at high supplemental doses of 1,000 mg or more, a theoretical concern for worsening kidney injury in people with existing kidney disease, a theoretical concern around estrogen-dependent cancers from animal data, and documented interactions that can alter the blood levels of certain medications Andres et al., 2018. This blend's entire ten-ingredient total is 481 mg a day, so quercetin alone cannot plausibly reach 1,000 mg here, but its exact share is unpublished.

Grape seed extract's one real randomized trial, 150 mg/day for a year in people with diabetic retinopathy, reported only mild gastrointestinal side effects and no serious safety signal Moon et al., 2019. That trial dose alone is close to a third of this entire blend, which is a reminder of how little room 481 mg leaves for ten ingredients at meaningful amounts.