The main AREDS report found no statistically significant serious side effect, and a 2023 Cochrane review found stomach and bowel symptoms were the main side effect reported, along with more genitourinary problems in men taking zinc in AREDS. Still, the doses are high: the zinc is twice the adult upper limit, vitamin E can add to bleeding risk, and several common medicines interact. Talk with your doctor or pharmacist before you start.
AREDS2 vitamins are sold over the counter, so it is easy to think of them like an everyday multivitamin. They are not. The doses are the ones tested in clinical trials of people with AMD, and some are several times higher than daily needs. Here is what the research says about side effects, and what to raise with your care team.
What the trials found about side effects
The first trial, AREDS Report No. 8, followed 3,640 people aged 55 to 80 for an average of 6.3 years. It found no statistically significant serious side effect from any of the formulas.
A Cochrane review (2023) of 26 randomized trials with 11,952 people found that gastrointestinal symptoms, such as stomach upset, were the main side effect. It also reported that in AREDS, zinc was linked to a higher risk of genitourinary problems in men. In AREDS2, there was no difference in these problems between the high and low zinc doses.
The NEI AREDS/AREDS2 FAQ adds that high-dose supplements can sometimes interfere with medicines and compete with other nutrients. NEI suggests giving your provider a list of every medicine, supplement and over-the-counter product you take.
Zinc: the dose to pay attention to
The AREDS2 formula contains 80 mg of zinc. According to the NIH Office of Dietary Supplements (ODS), the upper limit for adults is 40 mg a day.
ODS says taking 50 mg of zinc or more for weeks can interfere with copper absorption, lower immune function and reduce HDL cholesterol. That is why the formula includes 2 mg of copper. NEI says copper was added to reduce the risk of copper deficiency anemia, and that there is no evidence the 2 mg of copper was harmful.
ODS lists nausea, dizziness, headaches, stomach upset, vomiting and loss of appetite as signs of too much zinc. Some formulas use 25 mg of zinc instead. AREDS2 found no difference in AMD progression between 25 mg and 80 mg, but NEI still treats the 80 mg results as the gold standard because AREDS2 had no placebo group for zinc. Our article on zinc and copper for eye health explains the details.
Smokers and the original formula
AREDS2 found more lung cancers in former smokers taking the original formula's carotenoid, which is one reason it was replaced with lutein and zeaxanthin. According to the NEI FAQ, lung cancer occurred in 2% of people taking the original carotenoid versus 0.9% of those who were not, and about 91% of those cases were in former smokers.
NEI says current and former smokers should take the AREDS2 formula and avoid the original AREDS formula. If you smoke or used to, tell your eye doctor so they can help you check the label.
Vitamin E and bleeding
The ODS vitamin E fact sheet says large doses can raise bleeding risk in people taking blood thinners such as warfarin, probably at amounts above 400 IU a day. The NEI FAQ says AREDS and AREDS2 found no adverse effects from 400 IU a day, while other studies using more than 1,500 IU of the natural form or 1,100 IU of the synthetic form saw more bleeding.
NEI also addresses prostate cancer. A separate trial, SELECT, found a 17% increase with 400 IU of vitamin E a day for 7 years. AREDS and AREDS2 found no effect of high-dose vitamin E on prostate cancer risk.
Vitamin C, kidneys and iron
The ODS vitamin C fact sheet says high intakes can cause diarrhea, nausea and stomach cramps. High doses may raise the chance of kidney stones, especially in people with kidney problems, although the evidence is mixed. Vitamin C could also worsen iron overload in people with hemochromatosis. If either applies to you, talk with your doctor before starting.
Medicines to mention before you start
For quinolone antibiotics (such as ciprofloxacin) and tetracyclines, ODS advises taking the antibiotic at least 2 hours before or 4 to 6 hours after zinc. Penicillamine also has a timing interaction with zinc, so ask your pharmacist how to fit both into your day. Thiazide water pills can lower zinc levels in the blood.
ODS also notes that iron supplements of 25 mg or more taken at the same time can lower zinc absorption. Copper, by contrast, is not known to have any clinically relevant interactions with medicines.
Can you take AREDS2 with a multivitamin?
Yes, according to NEI. The AREDS formulas do not replace a multivitamin, and many trial participants took both: about two-thirds in AREDS and almost nine in ten in AREDS2. Because both products may contain zinc and vitamins C and E, ask your pharmacist to look at the total amounts.
Keep in mind: Bring your supplement bottles and medicine list to your next appointment. Your doctor or pharmacist can check for interactions with blood thinners, antibiotics, water pills, cancer treatment, or kidney and liver conditions.
Frequently asked questions
Should I take AREDS2 if I do not have AMD?
NEI says the formulas benefited people with intermediate or late AMD, with no benefit for people with early AMD or without AMD. That means the side effects and interactions above would come without a proven benefit. See Can AREDS2 Prevent Macular Degeneration? and What Is AREDS2 and Who Needs It?
Is the 25 mg zinc version safer?
The research does not answer that directly. Cochrane found no difference in genitourinary problems between high and low zinc in AREDS2, and progression rates were similar. NEI still points to 80 mg as the tested standard. Ask your eye doctor which dose fits you.
Can I take AREDS2 if I am on a blood thinner?
This is a question for your doctor or pharmacist. ODS says large doses of vitamin E can raise bleeding risk with medicines such as warfarin. The amount that matters is not known, but ODS says it is probably above 400 IU a day. The AREDS2 formula contains 400 IU.
If you are comparing formulas, our science page lists the doses used in the trials.
Related reading
- Zinc and Copper for Eye Health
- Vitamin C and Vitamin E for Eye Health
- AREDS2 Supplements Compared by Label
- The AREDS and AREDS2 Trials Explained
- Nutrition and Eye Health: What the Research Actually Shows
References
- Age-Related Eye Disease Study Research Group. AREDS report no. 8: randomized, placebo-controlled trial of high-dose antioxidant and zinc supplementation for age-related macular degeneration and vision loss. Arch Ophthalmol. 2001;119(10):1417-1436. doi:10.1001/archopht.119.10.1417
- Age-Related Eye Disease Study 2 Research Group. Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial. JAMA. 2013;309(19):2005-2015. doi:10.1001/jama.2013.4997
- Evans JR, Lawrenson JG. Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration. Cochrane Database Syst Rev. 2023;9:CD000254. doi:10.1002/14651858.CD000254.pub5
- NIH Office of Dietary Supplements. Zinc, Vitamin E, Vitamin C and Copper: Fact Sheets for Health Professionals. Zinc, Vitamin E, Vitamin C, Copper
- National Eye Institute. AREDS/AREDS2 Frequently Asked Questions. Updated November 19, 2020. nei.nih.gov
- National Eye Institute. About AREDS and AREDS2. Updated October 22, 2025. nei.nih.gov
This article is for general education and is not medical advice. Talk with your eye doctor before starting any supplement, especially if you smoke, take other medicines, or have a health condition. These statements have not been evaluated by the Food and Drug Administration. TruVista products are not intended to diagnose, treat, cure, or prevent any disease.
