According to Gram Research analysis, women with adequate vitamin D levels have significantly lower testosterone and related hormones compared to women with vitamin D deficiency, a 2026 cross-sectional study of 3,181 American women found. Women with healthy vitamin D (75 nmol/L or higher) had testosterone levels of 24.10 ng/dL versus 32.28 ng/dL in deficient women, while showing higher levels of reproductive hormones like FSH and LH. The research suggests vitamin D plays a role in hormone regulation, though it cannot prove vitamin D directly causes these changes.
A new study of over 3,000 American women found that those with healthy vitamin D levels had different hormone patterns compared to women with low vitamin D. Women with adequate vitamin D had lower levels of testosterone and other male-type hormones, but higher levels of hormones that help with reproduction. The research suggests vitamin D may play a role in how a woman’s body produces and manages sex hormones, though scientists say more research is needed to understand exactly how this connection works.
Key Statistics
A 2026 cross-sectional analysis of 3,181 American women from NHANES data found that women with adequate vitamin D levels had 25% lower testosterone (24.10 ng/dL) compared to vitamin D-deficient women (32.28 ng/dL).
According to the same 2026 study of 3,181 women, those with adequate vitamin D had 39% lower progesterone levels (139.05 ng/dL versus 229.73 ng/dL) compared to vitamin D-deficient women.
A 2026 analysis of 3,181 American women revealed that adequate vitamin D was associated with 109% higher follicle-stimulating hormone (50.30 mIU/mL versus 23.99 mIU/mL) compared to vitamin D deficiency.
The 2026 NHANES-based study of 3,181 women found that vitamin D-adequate women had lower body mass index (29.16 kg/m²) compared to deficient women (32.10 kg/m²), suggesting vitamin D may influence both hormones and weight.
The Quick Take
- What they studied: Whether vitamin D levels in the blood are connected to the amounts of sex hormones (like testosterone and estrogen) that women produce
- Who participated: 3,181 American women aged 18 to 80 years old who participated in a national health survey between 2021 and 2023
- Key finding: Women with healthy vitamin D levels had significantly lower testosterone and related hormones, but higher levels of reproductive hormones compared to women with vitamin D deficiency
- What it means for you: Getting enough vitamin D may help regulate your body’s hormone balance, though this study shows a connection rather than proving vitamin D causes these changes. Talk to your doctor about your vitamin D levels if you have hormone-related concerns.
The Research Details
Researchers used data from the National Health and Nutrition Examination Survey (NHANES), which is a large study that tracks the health of Americans. They looked at information collected from 2021 to 2023 and focused specifically on women. The women were divided into three groups based on their vitamin D blood levels: those with deficiency (very low), insufficiency (somewhat low), and adequate levels (healthy). The researchers then compared hormone levels between these groups using statistical tests to see if there were meaningful differences.
This type of study is called ‘cross-sectional,’ which means researchers took a snapshot of people at one point in time rather than following them over months or years. It’s like taking a photo instead of making a video. This approach is good for finding connections between things, but it can’t prove that one thing causes another.
Understanding how vitamin D relates to sex hormones is important because hormones affect many aspects of women’s health, including fertility, bone strength, mood, and metabolism. Most previous research focused on men or specific groups of women, so this study fills a gap by looking at a broad sample of American women. The findings could help doctors better understand why some women have hormone imbalances and whether vitamin D supplementation might help.
This study used data from a well-respected national health survey, which is a strength. The sample size of over 3,000 women is large enough to find real patterns. However, because this is a cross-sectional study, it can only show that vitamin D and hormones are connected—it cannot prove that low vitamin D causes hormone problems. The researchers used appropriate statistical methods to analyze the data. One limitation is that the study only included data from one time period, so we don’t know if these patterns stay the same over time.
What the Results Show
Women with adequate vitamin D levels had noticeably different hormone profiles compared to women with vitamin D deficiency. Specifically, women with healthy vitamin D had lower levels of testosterone (24.10 ng/dL versus 32.28 ng/dL), progesterone, and other male-type hormones. At the same time, they had higher levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are important for reproduction.
When researchers looked at the mathematical relationship between vitamin D and hormones, they found that for every increase in vitamin D, there was a decrease in testosterone, androstenedione (a hormone that converts to testosterone), and anti-Müllerian hormone (AMH). Conversely, higher vitamin D was associated with increases in FSH and LH. These patterns were consistent across the statistical tests used.
Interestingly, women with adequate vitamin D also had lower body weight on average (BMI of 29.16 versus 32.10), which could be related to the hormone differences since weight and hormones are connected. The researchers noted that these patterns were particularly strong in older women in the study.
The study also found that women with adequate vitamin D had higher levels of sex hormone-binding globulin (SHBG), a protein that carries hormones through the bloodstream. This is important because SHBG affects how much active hormone is available in the body. The relationship between vitamin D and various hormone precursors (building blocks for hormones) was also significant, suggesting vitamin D may influence the early stages of hormone production.
Previous research has mostly studied vitamin D and sex hormones in men or in specific populations like older adults or people with certain diseases. This study is notable because it examines a diverse group of American women across a wide age range. The findings align with some previous research suggesting vitamin D plays a role in hormone regulation, but they also add new information specific to women. The inverse relationship between vitamin D and testosterone in women is particularly interesting because it differs from some patterns seen in men.
This study has several important limitations. First, because it’s cross-sectional, we can’t determine whether low vitamin D causes hormone changes or whether hormone changes affect vitamin D levels—or if something else causes both. Second, the study only captured one moment in time, so we don’t know if these patterns persist over months or years. Third, the study couldn’t account for all factors that might affect hormones, such as medications, diet, exercise, or stress levels. Finally, while the sample was large, it was drawn from a specific national survey and may not perfectly represent all American women.
The Bottom Line
Based on this research, maintaining adequate vitamin D levels (75 nmol/L or higher) appears to be associated with healthier hormone patterns in women. The recommended approach is to: (1) Get your vitamin D level checked by your doctor, (2) Aim for adequate vitamin D through sunlight exposure, foods like fatty fish and fortified milk, or supplements if needed, (3) Discuss any hormone concerns with your healthcare provider. However, this study shows a connection, not proof of cause-and-effect, so vitamin D supplementation shouldn’t replace medical treatment for hormone disorders.
This research is relevant to all women interested in hormone health, particularly those experiencing irregular periods, fertility concerns, or symptoms of hormone imbalance. Women over 40 may find this especially relevant since the patterns were stronger in older women. However, women with specific hormone disorders should work with their doctors rather than self-treating with vitamin D supplements. Men should note this study focused on women and may not apply to them.
If you’re considering vitamin D supplementation to support hormone health, realistic expectations are important. Vitamin D builds up in your system over weeks to months, so you wouldn’t expect immediate changes. Most people see stable vitamin D levels after 8-12 weeks of consistent supplementation. Hormone changes may take longer to become noticeable.
Frequently Asked Questions
Does low vitamin D cause high testosterone in women?
This study found an association: women with low vitamin D had higher testosterone levels. However, the research cannot prove vitamin D deficiency causes high testosterone—the relationship could work the other way, or other factors could influence both. Consult your doctor about hormone concerns.
Should I take vitamin D supplements to balance my hormones?
While this research shows vitamin D is connected to hormone levels, it doesn’t prove supplementation will fix hormone problems. If you have hormone concerns, talk to your doctor first. They can test your vitamin D and hormones, then recommend appropriate treatment based on your individual situation.
What vitamin D level should women aim for?
This study defined adequate vitamin D as 75 nmol/L or higher. Most health organizations recommend 20-30 ng/mL (50-75 nmol/L) as sufficient, though some suggest higher levels. Your doctor can determine the right target for you based on your health and risk factors.
How long does it take for vitamin D to affect hormones?
Vitamin D builds up in your body over 8-12 weeks of consistent supplementation. Hormone changes may take longer to become noticeable. This study captured one moment in time, so we don’t know the exact timeline for hormone shifts from vitamin D changes.
Does this vitamin D and hormone connection apply to all women?
This study included American women aged 18-80, so the findings likely apply broadly to adult women. However, the patterns were stronger in older women. Individual factors like medications, diet, and health conditions affect your personal hormone-vitamin D relationship, so discuss your situation with your doctor.
Want to Apply This Research?
- Track your vitamin D supplementation (dose and frequency) alongside menstrual cycle regularity and any hormone-related symptoms. Record your vitamin D level from blood tests when available, noting the date and result.
- Set a daily reminder to take a vitamin D supplement if your doctor recommends it, or to spend 15-20 minutes in midday sunlight several times per week. Log this in your app to build consistency and see patterns over time.
- Check vitamin D levels every 6-12 months through your doctor, and track any changes in menstrual patterns, energy levels, or mood alongside your vitamin D status. Use the app to create a timeline showing correlations between vitamin D levels and hormone-related symptoms.
This research shows an association between vitamin D levels and sex hormones in women but does not prove that vitamin D deficiency causes hormone imbalances. This study cannot replace medical diagnosis or treatment. If you experience symptoms of hormone imbalance, irregular periods, fertility concerns, or other health issues, consult a qualified healthcare provider. Do not start, stop, or change any supplements or medications without discussing it with your doctor first. This article is for educational purposes only and should not be considered medical advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.