Women’s health: do vitamins help?
By: Dr. James Aw, Chief Medical Officer, OMERS
March 23, 2026
I often see female patients in my practice that are on multiple vitamins and supplements hoping to solve common health problems like poor sleep, brain fog, low energy, weight management, menopausal symptoms or stress. It is a challenge to navigate through the evidence because vitamins aren’t regulated and there is a mixed quality of studies. Also, the purity of vitamins (contamination/adulteration) and interindividual variabilities make it difficult to make conclusions about health benefits. Individuals often receive tips from friends and family who swear by the latest vitamin craze, and social media influencers tend to make claims without scientific credentials.
It might be helpful to ask yourself a few questions before starting a vitamin or supplement.
Do you even have any vitamin deficiencies? Check your levels
It’s helpful to check your biomarker levels with your physician if you are curious about starting vitamins or supplements. If your levels are OK, then you might not even have to take any vitamins, and daily overdosing might cause side effects. It is not necessary to check for all vitamin levels, but checking for Vitamin D, Calcium (bone health), iron (menstrual blood loss, dietary loss) and vitamin B12 (anemia, cognition, peripheral neuropathy) can help determine the need and dosing of supplementation.
Consuming a balanced daily healthy diet (Mediterranean style diet, avoiding ultra processed foods) is the best source of macro and micronutrients and should prevent deficiencies.
What health problem or symptom are you trying to solve?
Sleep can be improved with melatonin and magnesium. The evidence is moderate for valerian, vitamin D and passionflower, while Chamomile and L-theanine have some positive effects.
Brain health, mood (anxiety) and cognition might benefit from magnesium, creatine, lavender (silexan) and ashwagandha. Vitamin B12 deficiency affects brain and nerve function.
Bone health (post menopause) is maintained with vitamin D and calcium. Creatine helps with muscle strength.
Women trying to get pregnant should take daily folic acid supplementation to prevent neural tube birth defects. Omega-3 fatty acids have been associated with reducing pre-term births, pre-eclampsia and low birth weights. Omega-3 also has anti-inflammatory effects and may help with reducing cardiovascular disease risk. A maternal multivitamin is usually recommended during pregnancy. Otherwise, herbal supplements are generally discouraged during pregnancy because of concern for potential embryotoxic and teratogenic effects.
The evidence is weak and mixed for evening primrose oil and black cohosh for premenstrual syndrome, biotin for hair/nails and collagen supplements for skin aging (which are heavily marketed with industry-funded studies).
Studies have shown that multivitamins have no mortality benefit for cardiovascular and cancer prevention.
Can vitamins and supplements be harmful?
Most of the concerns are about liver damage (hepatoxicity) and/or drug interactions, particularly in women over the age of 50. Liver toxicity has been seen with black cohosh, green tea extracts, kava, turmeric, garcinia cambogia and ashwagandha. St. John’s wort can cause significant drug interactions with heart medication, immunosuppressants, HIV drugs, psychiatric medication and oral contraceptives (breakthrough bleeding, unwanted pregnancies). Other supplements can interact with drugs and increase bleeding (ginkgo, garlic).
Weight loss and energy supplements are the leading cause of supplement-related emergency visits (cardiac symptoms), particularly in younger women. Unnecessary high doses of supplements have been linked to increased hip fracture risk (vitamin A), hemorrhagic stroke risk (vitamin E), kidney stones (vitamin C and calcium), lung cancer, cardiovascular risk (beta carotene) and pregnancy-related complications like pre-eclampsia (antioxidant vitamin C and E, probiotics). Ashwagandha should not be used in pregnancy, as it has been linked with preterm labour.
A few words about magnesium and creatine
Magnesium helps with muscle relaxation, sleep, brain health and stress. It is difficult for most women to meet the necessary daily requirement (320 mg) through food. Dietary sources include nuts, leafy greens, seeds, legumes, whole grains and dairy. Chronic low levels of magnesium have been linked to increased risk of type 2 diabetes and heart disease (arrhythmia in severe cases). Magnesium supplements may also help with migraine prevention. Magnesium requirements increase during pregnancy and low levels can be linked to pre-eclampsia, gestational diabetes, preterm labour and low birth weight. A common side effect of magnesium supplementation is diarrhea.
Creatine is known for muscle building but may also improve cognitive function. Post-menopausal women benefit the most from Creatine if combined with muscle resistance training (to improve balance and avoid falls). Other women who benefit from creatine include vegetarians, athletes and those with treatment resistant depression.
Vitamins and supplements can help, but everyone’s response may be a little different
It is probably best to look at micro and macronutrient requirements along the continuum of women’s health. Requirements change depending on your stage of life. Vitamins and supplements aren’t perfect, but they help if you can’t maintain your daily healthy food requirements and well-being routines. Remember, it is best to always check first with your physician. Stay healthy!
For those who want to read more!
What Makes Nutrition Research So Difficult to Conduct and Interpret? Diabetes Spectr. 2020
Full article: Creatine monohydrate supplementation for older adults and clinical populations
Does valerian work for insomnia? An umbrella review of the evidence - ScienceDirect
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