The two formulas differ in one ingredient. That sounds minor and it is not, because of why the swap happened. Both came out of a pair of government trials with the same name as the formula, which is the source of most of the confusion here.
What the first trial established
The original Age-Related Eye Disease Study, run by the US National Eye Institute, was a large randomised trial that asked whether a high-dose antioxidant and zinc combination could slow age-related macular degeneration.
It found that it could, in a specific group. Among people with intermediate AMD, or advanced AMD in one eye, the formulation reduced the risk of progressing to advanced disease by around 25%, and reduced the risk of losing central vision by about 19%. For people with no AMD or only very early changes, it did nothing measurable.
That result is the foundation everything since rests on, and its narrowness is the part most often lost. It has never been a general eye vitamin, and it was never shown to prevent AMD from starting.
Then the beta-carotene problem arrived
Beta-carotene is a vitamin A precursor. It is what makes carrots orange, it is an antioxidant, and in food it is completely unremarkable. Putting it in the formula was an obvious call at the time.
At supplement doses it turned out to behave differently. Large trials investigating beta-carotene for cancer prevention found the opposite of what was expected: in smokers, high-dose beta-carotene was associated with an increased risk of lung cancer. The finding was robust enough to change practice, and it left the AREDS formula carrying an ingredient that a substantial share of its target population should not take.
A nutrient that is harmless in a carrot is not automatically harmless in a capsule. Dose changes the answer, and the only way to find out is to test it.
This is worth sitting with, because it is the strongest argument against the reasoning that sells most supplements. The logic that put beta-carotene in the formula, that it is an antioxidant found in healthy food, is exactly the logic used to sell dozens of products today. It was reasonable. It was also wrong in a way nobody predicted from first principles.
What AREDS2 actually tested
The second trial, which reported in 2013, was designed to answer several questions at once rather than just make the substitution. It enrolled 4,203 participants aged 50 to 85, ran from 2006 to 2012, and followed them for a median of five years. Everyone stayed on the AREDS formulation or a variant of it, so this was never a trial of AREDS2 against nothing. It was a trial of what to change.
It asked four things. Would adding lutein and zeaxanthin help? Would adding omega-3 help? Could beta-carotene come out without cost? Could the zinc dose come down?
The two additions, and what they did
Neither worked, and this is the part almost nobody reports. Five-year progression to advanced AMD was 31% on placebo, 29% with lutein and zeaxanthin, 31% with omega-3, and 30% with both. The hazard ratio for lutein and zeaxanthin was 0.90 with a confidence interval of 0.76 to 1.07, which includes 1, and p was 0.12.
The primary result of AREDS2 was negative. Adding either nutrient to the AREDS formulation did not further reduce progression, and omega-3 in particular changed nothing at all despite having the best mechanistic case in the trial. The whole arithmetic is in does AREDS2 actually work.
The two subtractions, which is where the answer was
Removing beta-carotene cost nothing in effect: hazard ratio 1.04 for no beta-carotene against beta-carotene. Lowering zinc from 80 mg to 25 mg cost nothing either: hazard ratio 1.04, confidence interval 0.94 to 1.14.
So the trial did not find a better formula. It found that one ingredient could be removed for free, and it already had a safety reason to want that. The substitution followed from the subtraction, not from the addition.
And then, ten years later
In 2022 the investigators went back to 3,882 of the participants. Comparing lutein and zeaxanthin directly against beta-carotene, the hazard ratio for progression to late AMD was 0.85, interval 0.73 to 0.98, which does not cross 1. The odds of having had lung cancer were 1.82 times higher in the beta-carotene group.
That is the closest thing to evidence that the swap improved the formula rather than merely made it safer. It is also an epidemiologic follow-on rather than the randomised comparison, which is weaker, and the difference matters enough to say out loud.
- Can lutein and zeaxanthin replace beta-carotene? Yes. The substituted formulation performed at least as well, and the two carotenoids have a more direct rationale than beta-carotene ever did, since they are the pigments the macula physically concentrates.
- Does removing beta-carotene cost anything? No. Effectiveness held. This is the finding that made the change straightforward rather than a trade-off.
- Does a lower zinc dose work as well? Yes. Reducing zinc from 80 mg to 25 mg made no difference to the result. The investigators had hoped the lower dose would also reduce side effects such as stomach upset, and the trial did not show that either.
- Does adding omega-3 help? No. Adding DHA and EPA produced no additional benefit. This is unusually clean negative evidence, and it is why omega-3 is not part of the formulation despite appearing on many eye supplements.
What did not change, which is most of it
People hear AREDS2 and picture a new generation. Put the two panels side by side and the impression does not survive.
| Ingredient | AREDS, 2001 | AREDS2, current |
|---|---|---|
| Vitamin C | 500 mg | 500 mg |
| Vitamin E | 400 IU | 400 IU |
| Zinc | 80 mg | 80 mg or 25 mg |
| Copper | 2 mg | 2 mg |
| Beta-carotene | 15 mg | none |
| Lutein | none | 10 mg |
| Zeaxanthin | none | 2 mg |
Amounts as used in the two trials. Four of the six original ingredients are untouched, including the zinc that carries much of the effect and the copper that offsets it. One ingredient came out, and two went in to take its place.
Vitamin C, vitamin E, zinc and copper are identical. The entire difference is that beta-carotene left and the two macular carotenoids arrived. That is also why the 25% from 2001 still describes what is on the shelf today: the part of the formula the effect was measured on never moved.
The other difference, which is on shelves and rarely discussed
Beta-carotene is not the only thing that varies between products calling themselves AREDS2. The zinc does too, and it is a legitimate difference rather than a shortcut.
AREDS2 tested 25 mg against the original 80 mg and found no difference in effect. Both are therefore defensible. And every zinc-related safety signal recorded in the first trial was recorded at 80 mg: genitourinary hospitalisations 7.5% against 4.9%, rising to 8.6% against 4.4% among men. We set out what the trials recorded on safety separately.
So a product at 25 mg is not a weaker version of one at 80 mg. It is the same evidence with a smaller dose of the ingredient that carries the side effects, and no box will ever present it that way.
Which formula applies to you
In practical terms the question is mostly settled. AREDS2 is the current formulation and there is no reason to seek out the original.
The practical position
The original AREDS formula
- Contains beta-carotene at 15 mg.
- Unsuitable for current or former smokers.
- Superseded, with no advantage over AREDS2.
- Still occasionally found on shelves and in cupboards.
AREDS2
- Lutein and zeaxanthin instead of beta-carotene.
- No smoking-related safety concern.
- At least as effective in trial.
- The formulation to look for.
Beyond that, the choice between products comes down to whether a given label reproduces the tested formulation, which is a different exercise from picking a brand. We go through what to actually check and what each ingredient is doing separately.
And the prior question has not changed across either trial: both found benefit only in people who already have intermediate AMD, or advanced AMD in one eye. If that is not you, neither formula has anything to offer.