Vitamin Quiz: What Vitamins Should I Take?
Answer 18 questions about what you eat, sun, age, and medicines. The vitamin quiz lists what supplements to look at — and which ones you can skip.
The list answers what vitamin supplements should I take from how you eat, how much sun you get, and your age. It also shows what you can skip. It is a diet screen, not a blood test, so it will not tell you what vitamin you are deficient in.
Daily targets below follow NIH Office of Dietary Supplements and National Academies dietary reference intakes. Educational only — not a diagnosis or a prescription.
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Key takeaways
- Most adults do not need a long supplement shelf. Vitamin D, vitamin B12, and omega-3 are the usual short list.
- Daily targets are totals from food, sun, and pills together. They are not a bottle size.
- Adults 19–70 need 600 IU of vitamin D. Age 71+ needs 800 IU. The supplemental cap from age 9 is 4,000 IU.
- Iron and a prenatal belong with a clinician. This quiz will not tell you what vitamin you are deficient in.
- A second multivitamin on top of one you already take is how people double vitamin A and iron by accident.
What vitamins do I need daily?
These are adult recommended dietary allowances from the National Academies, as published by the NIH Office of Dietary Supplements. Food, fortified food, sun, and supplements all count toward the same total. Pregnancy and lactation use a prenatal for folate and iron, not this table.
| Nutrient | Women | Men |
|---|---|---|
| Vitamin D, ages 19–70 | 600 IU (15 mcg) | 600 IU (15 mcg) |
| Vitamin D, age 71+ | 800 IU (20 mcg) | 800 IU (20 mcg) |
| Vitamin B12 | 2.4 mcg | 2.4 mcg |
| Folate | 400 mcg DFE | 400 mcg DFE |
| Vitamin C | 75 mg | 90 mg |
| Vitamin A | 700 mcg RAE | 900 mcg RAE |
| Calcium, ages 19–50 | 1,000 mg | 1,000 mg |
| Calcium, later adulthood | 1,200 mg from age 51 | 1,200 mg from age 71 |
| Iron | 18 mg ages 19–50, then 8 mg | 8 mg |
| Iodine | 150 mcg | 150 mcg |
Vitamin C, vitamin A, and folate are easy to hit with fruit, vegetables, dairy, and fortified grains. The gaps that show up on this quiz are the ones food and sun often miss: vitamin D indoors, vitamin B12 without animal foods or after 50, and omega-3 when fatty fish is rare.
What vitamin supplements should I take?
Match a supplement to a gap you can name. A bottle you bought because a shelf looked complete is how people end up with three products that all contain vitamin D.
| Supplement | Look at it when | Skip it when |
|---|---|---|
| Vitamin D3 | Little midday sun, age 71+, or a vegan diet | You already take it inside a multi, or a blood test is already high |
| Vitamin B12 | Vegan or vegetarian diet, age 50+, metformin, or a daily acid reducer | You eat animal foods regularly and you are under 50 with no absorption issue |
| Omega-3 (EPA+DHA) | Fatty fish less than twice a week. Algae oil if you do not eat fish | You already eat salmon, sardines, or mackerel twice a week |
| Iron | Only after a ferritin test, usually with heavy periods or a low result | You have not had a blood test. Extra iron when you are not low can harm you |
| Prenatal | Pregnant or trying, ideally started before conception | You are not pregnant or breastfeeding. Do not stack it on a second multi |
| Iodine | No iodized salt, and little dairy or seafood | You already use iodized salt. Skip kelp drops |
What are the best vitamins to take?
For a lot of adults the best vitamins to take are vitamin D3 and, when the diet requires it, vitamin B12. “Best” is not a 12-bottle shelf. If meals already cover fish, dairy or fortified drinks, fruit, and vegetables, the best vitamin is often none. A basic multivitamin can cover small holes when the menu is very limited. The vitamin D and B12 inside a typical multi are often modest, so read the label before you add a second pill of the same nutrient.
Vitamin C pills, hair-skin-nails blends, and megadose B-complex products are the ones this quiz does not put on a default list. One piece of fruit covers the vitamin C target. Extra vitamin A on top of a multi is the overlap most worth avoiding.
What vitamin am I deficient in?
A what vitamin am I deficient in quiz can only guess from habits. Low sun points at vitamin D. No animal foods points at vitamin B12. Heavy periods point at iron. Fatigue overlaps all three and also overlaps poor sleep, low calories, and thyroid problems, so tiredness alone is not a vitamin name.
The lab that matches the guess is specific. Vitamin D is a 25-hydroxyvitamin D test. B12 is a serum B12, sometimes with methylmalonic acid if the result is borderline. Iron status is ferritin, not “I feel pale.” Start the pill after the test when the nutrient is iron. For vitamin D and B12, a standard daily dose is the usual maintenance step while you wait, not a megadose.
How much vitamin D should I take?
This page only decides whether vitamin D belongs on your list. The amount depends on age, sun, body weight, skin, and a blood test. Adults 19–70 need 600 IU (15 mcg) a day. Age 71 and older needs 800 IU (20 mcg). Limited sun often means 1,000–2,000 IU of vitamin D3. Stay at or under 4,000 IU (100 mcg) unless a clinician sets a higher short-term dose.
| Daily D3 | mcg | Who it usually fits |
|---|---|---|
| 600–800 IU | 15–20 mcg | The official daily need. Enough for many people who also get some sun or fortified food. |
| 1,000–2,000 IU | 25–50 mcg | Indoors most days, older age, or little vitamin D in the diet. |
| 4,000 IU | 100 mcg | The adult upper limit. Not a starting dose. |
Take vitamin D with a meal that contains fat. Windows block the UVB that makes it in skin. Use the vitamin D calculator when you want IU from sun, weight, or a 25-hydroxyvitamin D result.
Vitamin B12
The adult target is 2.4 mcg a day. Meat, fish, eggs, and dairy contain it. Plants do not, unless the food is fortified. A vegan diet needs a supplement or fortified foods. Vegetarians often still run low because dairy and eggs are an uneven source. After 50, stomach acid absorbs B12 from food less reliably, so fortified food or a pill is easier to absorb even if you eat meat.
Metformin and daily acid reducers such as omeprazole have the same absorption problem. Weight-loss or stomach surgery does too. Those are reasons to ask for a B12 test, not reasons to take an unlabeled megadose on top of a multi that already has some.
Iron, folate, and vitamin C
Women 19–50 need 18 mg of iron a day. Men, and women 51 and older, need 8 mg. Meat, legumes, and fortified cereal cover it, especially with fruit or vegetables at the same meal. Do not start an iron supplement from this quiz. Heavy periods plus fatigue deserve a ferritin test first.
Folate is 400 mcg DFE for adults, from leafy greens, beans, and fortified grains. Drinking most days raises the need. A folic-acid pill is the pregnancy product, not the default for everyone else. Vitamin C is 75 mg for women and 90 mg for men. One piece of fruit or a serving of peppers or broccoli covers it. A vitamin C pill is unnecessary once that food is back.
Calcium, iodine, and omega-3
Calcium is 1,000 mg for most adults, and 1,200 mg for women from 51 and for everyone from 71. Dairy, fortified drinks, tofu set with calcium, and some greens are the foods. Supplement only the gap the food does not cover, and split the dose. A calcium pill is a poor swap for a diet that never includes a calcium food.
Iodine is 150 mcg. Iodized salt, dairy, and seafood are the usual sources. Sea salt and kosher salt are usually not iodized. If those foods are missing, stay near 150 mcg. Kelp and high-dose drops are easy to overdo.
Omega-3 is not a vitamin. There is no official RDA for EPA and DHA. About 250 mg combined is a common intake when fatty fish is rare. Two fish meals a week is the food fix. Algae oil is the match for a vegan diet. Once a week is close enough that a pill is optional.
Should I take a multivitamin every day?
A basic multivitamin can cover small gaps when meals are skipped or the menu is very short. It is a poor substitute for a prenatal in pregnancy, and it is unnecessary when the diet is already varied. Do not stack a multivitamin on a prenatal: you double iron and folate. If you already take a multi, check it before buying standalone vitamin D or B12.
A prenatal used by someone who is not pregnant or breastfeeding is the wrong product. It is built with more iron and folate than most other adults need.
How this vitamin quiz decides the list
Eighteen questions cover diet pattern, vegetables, fruit, fish, dairy, meat or legumes, eggs, skipped meals, sun, how easily you burn, age, pregnancy or periods, energy, medicines that block B12, alcohol, iodized salt, bones, and what you already take. Each answer turns a nutrient on or leaves it off. A varied diet with regular sun and no blocking medicine can come back with an empty stack. That is a result, not a broken quiz.
The list is a habit screen. It is not a diagnosis, a prescription, or a blood test.