What supplements should I take is a question with a shorter answer than the shelf suggests: for most healthy adults, few, and each for a reason you can name. Food covers most of what the body needs; a supplement earns its place when a measured shortfall, a stage of life or a diet leaves a gap that food is not closing. This page sets out the daily amounts the NIH gives for the nutrients women over 40 most often fall short on, the cases where a supplement is worth it, what the evidence says about multivitamins, and every guide in this site’s supplements section.
Food First, and How Much of Each
The amounts below are the NIH’s recommended daily intakes for adult women, which count everything eaten and drunk, not a supplement on its own. A supplement is for the gap between what a normal week of food supplies and these figures, and the gap is different for each nutrient.
| Nutrient | Daily amount (women) | Where the gap usually comes from |
|---|---|---|
| Vitamin D | 600 IU (15 mcg) to age 70, 800 IU after; upper limit 4,000 IU | Little sun in winter, indoor days; few foods carry much of it |
| Calcium | 1,000 mg to age 50, 1,200 mg from 51; upper limit 2,000 mg after 50 | Diets with little dairy or fortified alternatives |
| Vitamin B12 | 2.4 mcg | Deficiency is most common over 50; the B12 in fortified food and supplements is the easiest to absorb |
| Iron | 18 mg to age 50, 8 mg from 51 | Heavy periods; the need drops by more than half after menopause |
| Magnesium | 310 mg to age 30, 320 mg from 31 | Diets low in leafy greens, nuts, seeds and whole grains; supplements are not advised without a reason |
When a Supplement Is Worth It
Four cases come up again and again after 40. Vitamin D in the darker half of the year, because the need is met mostly from sun on skin and a blood test settles whether the level is low. Vitamin B12 from fortified food or a supplement from 50 on, because deficiency is most common over that age and the B12 in fortified foods is the easiest kind to absorb; anyone eating no animal food needs it at any age. Iron when periods are heavy, and only then: after menopause the need falls to 8 mg and extra iron has nowhere to go. And calcium when the diet cannot reach 1,200 mg a day from 51, which is when bone loss speeds up, taken as food first and a supplement for the shortfall. Creatine sits apart from these: it is not a nutrient you can be short of, but with strength training it helps older adults keep muscle and strength, and the creatine calculator sets the dose from body weight.
What a Multivitamin Does and Does Not Do
The US Preventive Services Task Force reviewed the trials in 2022 and found the evidence insufficient to say whether a multivitamin prevents heart disease or cancer in healthy adults, and the same for single vitamins and minerals taken for that purpose; it recommends against beta carotene and vitamin E supplements for it. That is the honest position: a multivitamin is a hedge against small gaps, not a protection against disease, and the nutrients above are better taken as themselves, in the amounts above, when there is a reason. The guides below take each supplement on this site’s list in turn, with what the research measured rather than what a label promises.
The Guides
Vitamins and Minerals
- Vitamin D deficiency symptoms in women
- Vitamin D3 and K2 together for bone and heart
- Vitamin B12 deficiency signs in women
- Vitamin B complex for women
- Low ferritin symptoms in women
- Signs of magnesium deficiency in women
- Magnesium glycinate for sleep and anxiety
- A multivitamin for women over 40: what to look for
- A multivitamin with iron for women over 40
- Why vitamins matter and what each does
Supplements
- Creatine for women over 40: what the science says
- Omega-3 fish oil for women
- CoQ10 for energy and fatigue
- Turmeric and curcumin for inflammation
- Probiotics for gut health: which strains
- Supplements for perimenopause weight gain
- Five supplements studied for immune function
New guides land in the Supplements section, which lists every one with its date.
Frequently Asked Questions
What supplements should a woman over 40 take?
Only the ones with a reason. The common ones are vitamin D in winter or when a blood test shows a low level, vitamin B12 from 50 or on a diet without animal food, iron while periods are heavy, and calcium if the diet falls short of 1,200 mg a day from 51. With strength training, creatine helps keep muscle. A multivitamin is a hedge, not a treatment.
How much vitamin D should I take?
The NIH’s recommended intake is 600 IU a day to age 70 and 800 IU after, from all sources, with an upper limit of 4,000 IU a day. A blood test is the way to know whether you are low and how much to take; more is not better past the upper limit.
Do I need iron after menopause?
Usually not as a supplement. The recommended intake falls from 18 mg a day to 8 mg at 51 because there is no monthly loss, and iron taken without a need builds up. Heavy periods before then, or a low ferritin on a blood test, are the reasons to take it.
Is a multivitamin worth taking?
As a hedge against small gaps in an ordinary diet, it does no harm at the recommended amounts. As protection against heart disease or cancer, the US Preventive Services Task Force found the evidence insufficient in 2022, and it recommends against beta carotene and vitamin E for that purpose.
Should I take supplements with food?
Iron is best absorbed on an empty stomach, and a little food is the answer if it upsets the stomach; vitamin C with it helps it absorb. Calcium is best split into doses of 500 mg or less, because the body absorbs less of a larger one at a time. Creatine goes with any meal.
Sources
- Vitamin D · MedlinePlus Medical Encyclopedia (NIH)
- Calcium in diet · MedlinePlus Medical Encyclopedia (NIH)
- Vitamin B12 · MedlinePlus Medical Encyclopedia (NIH)
- Iron in diet · MedlinePlus Medical Encyclopedia (NIH)
- Magnesium in diet · MedlinePlus Medical Encyclopedia (NIH)
- Taking iron supplements · MedlinePlus Medical Encyclopedia (NIH)
- Calcium: Fact Sheet for Consumers · NIH Office of Dietary Supplements
- Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer: US Preventive Services Task Force Recommendation Statement · JAMA, 2022
- International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation · Kreider et al., 2017 (PMC)
This page is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment.