There is no single recommended daily amount for “antioxidants” because the term covers dozens of different nutrients and plant compounds, each with its own intake target. For the antioxidant vitamins and minerals that do have official guidelines, the numbers are surprisingly modest: 75 to 90 mg of vitamin C, 15 mg of vitamin E, and 55 micrograms of selenium per day for adults. Beyond those, the largest category of dietary antioxidants, polyphenols, has no established recommendation at all.
That lack of a neat number frustrates people, but it reflects something important about how antioxidants actually work in the body. Understanding why there’s no universal target will help you make better choices than chasing a number on a supplement label.
Official Targets for Antioxidant Nutrients
Only a handful of antioxidants have Recommended Dietary Allowances set by nutrition authorities. These are the ones with enough research to pin down how much your body needs:
- Vitamin C: 90 mg per day for men, 75 mg for women. A single orange or a cup of strawberries gets you there.
- Vitamin E: 15 mg per day for all adults. A small handful of almonds or sunflower seeds covers most of this.
- Selenium: 55 micrograms per day for all adults. One or two Brazil nuts contain more than a full day’s worth.
No dietary reference intakes have been set for carotenoids like beta-carotene and lycopene, despite their antioxidant activity. The same is true for the thousands of polyphenols found in fruits, vegetables, tea, coffee, and wine. The science simply isn’t precise enough to assign a number.
What About Polyphenols?
Polyphenols are the largest group of antioxidants in most people’s diets, found in everything from berries and dark chocolate to olive oil and green tea. Epidemiological studies suggest that roughly 900 mg to 1 to 2 grams per day is associated with lower chronic disease risk. In studies of people eating a traditional Mediterranean diet, average intake reached around 1,900 mg per day.
But these are observational figures, not prescriptions. Researchers have acknowledged that establishing a dietary reference intake for polyphenols is difficult and hasn’t been done. People who eat lots of polyphenol-rich foods also tend to eat more vegetables, exercise more, and smoke less, making it hard to isolate the effect of polyphenols alone. The practical takeaway is that eating a variety of colorful fruits, vegetables, whole grains, nuts, and beverages like tea and coffee naturally pushes your polyphenol intake into that range without any counting required.
Why There’s No Universal Antioxidant Number
For years, a measurement called the ORAC score (Oxygen Radical Absorbance Capacity) was used to rank foods by antioxidant power, and supplement companies marketed products based on these scores. The USDA eventually pulled its ORAC database from the web, citing mounting evidence that the values have no relevance to actual health effects in humans. The scores measured what happened in a test tube, but your body doesn’t work like a test tube.
There are several reasons the test-tube-to-body leap doesn’t hold up. Your gut absorbs only a fraction of the polyphenols you eat, and then your liver modifies them further. The concentrations that reach your bloodstream are far lower than what researchers test in a lab dish. On top of that, your body runs its own powerful internal antioxidant defense system, producing compounds like glutathione that neutralize damaging molecules around the clock. Dietary antioxidants supplement this system rather than replacing it, which means more isn’t automatically better.
Antioxidants work by donating electrons to unstable molecules called free radicals, which would otherwise steal electrons from your cells and damage them. This acts as a natural off switch, breaking a chain reaction before it spreads. But this process needs to stay in balance. Your body actually uses some free radicals for immune signaling and other essential functions, so flooding the system with excess antioxidants can interfere with those processes.
The Risk of Taking Too Much
High-dose antioxidant supplements don’t just fail to help. They can cause harm. A major Cochrane review analyzing 78 clinical trials with nearly 300,000 participants found that antioxidant supplements had no overall benefit for preventing death. When researchers narrowed the analysis to only the most rigorous trials, supplements were associated with a statistically significant 4% increase in mortality risk. In the strictest subset of well-designed trials, that risk rose to 10%.
The picture varies by nutrient. Beta-carotene supplements and vitamin E supplements each independently increased mortality risk in high-quality trials. Vitamin C and selenium supplements did not show a significant effect in either direction. These findings apply to supplement doses, which are typically many times higher than what you’d get from food.
The European Food Safety Authority sets tolerable upper intake levels to flag where risk begins. For vitamin E, the upper limit is 300 mg per day, twenty times the RDA. For selenium, it’s 255 micrograms per day, about five times the RDA. Vitamin C doesn’t have a formal upper limit due to insufficient data, though very high doses commonly cause digestive upset. Staying below these ceilings matters most for people taking supplements, since it’s nearly impossible to exceed them through food alone.
A Food-First Approach Works Best
The consistent finding across decades of research is that antioxidants from food are associated with health benefits, while antioxidants from high-dose supplements are not, and may carry risk. This likely comes down to context. When you eat a handful of blueberries, you’re getting vitamin C, polyphenols, fiber, and dozens of other compounds that work together. A supplement isolates one compound and delivers it at a concentration your body never evolved to handle.
Rather than tracking milligrams, a more practical strategy is to eat a wide variety of plant foods. Different colors signal different antioxidant compounds: the red in tomatoes comes from lycopene, the orange in carrots from beta-carotene, the purple in grapes from anthocyanins. Aiming for five or more servings of fruits and vegetables a day, choosing whole grains over refined ones, and including nuts, seeds, tea, or coffee in your routine will reliably deliver antioxidants across every category, without the risks that come with megadosing any single one.
If you eat this way, you don’t need to count ORAC scores or milligrams of polyphenols. Your body’s own antioxidant systems, supported by a varied diet, handle the rest.