Vitamin D in perimenopause and after

Vitamin D matters for bone, and the years around the final period are when bone is most at risk, so meeting the recommended intake is sensible. But the two largest trials in US women found that supplementing people who are not deficient does not prevent fractures, cancer or heart disease. The useful questions are whether you are getting enough, not whether more is better.

What it is

Vitamin D is a fat-soluble vitamin made in skin exposed to UV light and found in a few foods: fatty fish, fish liver oil, egg yolks, beef liver, and in the US mostly fortified milk and cereal. It is inert until the liver converts it to 25-hydroxyvitamin D, the form measured in blood, and the kidney then activates it. Its core job is calcium absorption and bone mineralization. Supplements come as D2 (ergocalciferol) or D3 (cholecalciferol); both raise blood levels, but D3 raises them more and holds them longer.

Why women in midlife take it

Estrogen helps hold bone, and bone loss speeds up across the menopause transition and the years just after, which is why fracture prevention becomes a midlife conversation. Vitamin D is also widely promoted for mood, immunity, fatigue and hot flashes, usually without trial support. Many women are started on it after a routine blood test flags a “low” level.

What the evidence shows

Bone and fractures. The Office of Dietary Supplements summarizes decades of trials this way: vitamin D with calcium may increase bone density in some postmenopausal women, but it is not clear this reduces falls or fractures.

The Women’s Health Initiative tested this directly in 36,282 postmenopausal women aged 50 to 79 randomized to 1,000 mg of elemental calcium plus 400 IU of vitamin D3 daily or placebo for an average of 7 years. Hip bone density was 1.06 percent higher with supplements. Hip fracture risk was 12 percent lower (hazard ratio 0.88), but the confidence interval included no effect, and total fractures did not differ. Kidney stones rose 17 percent. Among women who actually took the pills, hip fracture risk was reduced (hazard ratio 0.71).

VITAL answered the higher-dose question. Among 25,871 US adults (men 50 and older, women 55 and older, half women) randomized to 2,000 IU of D3 daily or placebo, 1,991 fractures occurred over a median 5.3 years. Vitamin D did not reduce total fractures (hazard ratio 0.98), nonvertebral fractures or hip fractures, and results did not differ by baseline blood level, age, sex, race or body mass index. Participants were not selected for deficiency or low bone mass, which is exactly the population most supplement buyers fall into.

Cancer and heart disease. VITAL’s primary report found that 2,000 IU daily did not reduce invasive cancer or major cardiovascular events. ODS notes that clinical trials have generally failed to show that vitamin D lowers cancer incidence, and that several trials found no cardiovascular benefit even in people with low levels.

Depression, diabetes, weight. Supplementation has not prevented depression or improved depressive symptoms in trials. It does not appear to help glucose control in people already replete, although the Endocrine Society’s 2024 review found moderate-certainty evidence that it reduces progression from prediabetes to diabetes. It does not promote weight loss.

The 2024 Endocrine Society guideline. Its supporting review of 151 studies found no significant effect of vitamin D on selected outcomes in healthy adults aged 19 to 74, a very small reduction in mortality in adults over 75 (high certainty), and a signal that high-dose intermittent regimens may increase falls compared with daily dosing. It found no trials of the benefits or harms of screening.

Testing. The USPSTF concluded in 2021 that evidence is insufficient to recommend for or against screening asymptomatic adults, noting there is no consensus cutoff for deficiency.

Dose and form

The RDA is 600 IU (15 mcg) daily for adults 19 to 70 and 800 IU (20 mcg) from 71, with a Tolerable Upper Intake Level of 4,000 IU (100 mcg) for adults. Labels now list vitamin D in micrograms and often IU as well; 1 mcg equals 40 IU. D3 is the form to prefer. Daily dosing is better supported than large intermittent doses. Vitamin D is absorbed somewhat better with a meal containing fat.

Groups at higher risk of low levels: older adults, people with limited sun exposure, people with dark skin, people with conditions that limit fat absorption, people with obesity, and anyone who has had gastric bypass. Vegans and people who avoid milk get less from food.

Safety, interactions and who should be careful

Toxicity causes high blood and urine calcium and, in severe cases, kidney failure, soft-tissue calcification and arrhythmias. It almost always comes from supplements, not sun or food. Combining calcium and vitamin D supplements raises the risk of some adverse effects, including kidney stones, as WHI showed.

Interactions: orlistat reduces absorption; steroids lower blood levels; statins and vitamin D may affect each other’s levels; thiazide diuretics with vitamin D can cause hypercalcemia. None is reported with hormone therapy, SSRIs or thyroid medication, but share your full list with a pharmacist.

How to choose a product

Look for vitamin D3 and check the Supplement Facts panel for the amount in mcg or IU per serving, not per bottle. A product near the RDA (600 to 800 IU) suits most people without a documented deficiency; stay under 4,000 IU unless a clinician has prescribed more. Single-ingredient D3 makes the dose easier to see than a “bone complex.” If you also take calcium, count total elemental calcium from food and supplements before adding more. Choose a USP Verified or NSF certified product, which confirms the product contains the declared amount; see our guide to third-party testing. Our guide to reading a supplement label shows where these numbers sit.

Bottom line

Aim for the RDA from food, fortified milk, sensible sun and, if needed, a modest D3 supplement. Do not expect it to prevent fractures, cancer or heart disease on its own; the trials say it will not if you are already replete. If you have risk factors for bone loss, ask for a bone density test and a conversation about the full range of options, which is where a menopause-literate clinician earns their keep. See how to find a menopause specialist or the clinician finder.