There's a quiet frustration many women share at a surgery. You describe your symptoms. You're told the results are "within normal range". You leave with little clarity and a vague sense that something is still being missed.
You're probably not imagining it. For most of the 20th century, women were systematically excluded from clinical and nutritional research. The reasons were often framed as protective - concerns around hormonal fluctuations, pregnancy risk, and the complexity of studying cycling bodies. The result was a medical and nutritional framework built almost entirely on male data, then applied to women as though the differences didn't matter. They do matter. Quite a lot, as it turns out.
The research gap that shaped everything
The exclusion of women from medical and nutritional research didn't begin in the 1970s - it was baked into the foundations of modern clinical science. For most of the 20th century, male physiology was treated as the universal default, and female biology - with its hormonal cycles and life-stage transitions - was considered a complicating variable rather than a subject worth studying in its own right.
In 1977, the FDA made this explicit (1) by formally recommending the exclusion of women of childbearing potential from early-phase clinical trials, a policy that remained in place until 1993. But by then, the damage was already generational.
A widely-cited analysis by Beery and Zucker(2) found that in pharmacology research, studies using exclusively male animals outnumbered those using exclusively females by 5 to 1.The assumption was that male physiology was the neutral default.
The downstream effects of this are still playing out in clinical practice, supplement formulations, and the health advice women receive every day.
Where it shows up in practice
Cardiovascular health
Heart disease is the leading cause of death in women globally, yet it was long considered a "male condition." The classic symptoms taught in medical training - crushing chest pain, pain radiating down the left arm - are more typical in men. Women are more likely to experience fatigue, nausea, jaw pain, and breathlessness. Because these symptoms weren't part of the original research picture, they were frequently misattributed or dismissed. Studies from the British Heart Foundation have found that women are 50% more likely(3) to be misdiagnosed following a heart attack than men.
Sleep and energy
Women are significantly more likely to experience insomnia, yet most foundational sleep research was conducted on male subjects. Hormonal fluctuations across the menstrual cycle, perimenopause, and menopause have profound effects on sleep architecture, but these weren't factored into the frameworks clinicians and researchers used for decades. The result is that women presenting with sleep and fatigue complaints are still, in 2026, more likely to be offered anxiety or depression diagnoses than investigation into hormonal or nutritional causes.
Iron needs across life stages
The recommended daily intake for iron in adult women is almost double that of men, 14.8mg versus 8.7mg for adults in the UK(4), yet iron deficiency remains one of the most underdiagnosed conditions in women. Symptoms like fatigue, brain fog, and cold intolerance are easily attributed to stress or lifestyle. Women in their reproductive years lose iron monthly through menstruation, and those with conditions like endometriosis, which affects an estimated 1 in 10 women in the UK, are at significantly higher risk of deficiency due to heavier blood loss. Despite this, testing is inconsistently offered, and the conversation rarely happens proactively.
Omega-3 and hormonal health
This one is particularly relevant to us, and the research here is striking. Omega-3 fatty acids, specifically EPA and DHA, play a documented role in reducing inflammation, supporting mood regulation, and maintaining cardiovascular health. But the way omega-3 needs shift across a woman's life is rarely discussed.
During pregnancy and breastfeeding, DHA requirements increase substantially to support foetal brain development(6). During perimenopause and menopause, as oestrogen's cardioprotective effects decline, adequate omega-3 intake becomes increasingly important(8). Research has also suggested that omega-3 may help reduce the severity of menstrual pain(7), relevant for the millions of women managing primary dysmenorrhea or the symptoms of endometriosis. Yet standard supplement dosages were largely set based on male study populations, and women are rarely advised to adjust their intake around life stage.
The gap between "standard" doses and what women actually need
Most supplement labels are built on Reference Nutrient Intakes (RNIs) - population-level averages designed to prevent deficiency in most people, most of the time. They are not designed to optimise health for women at different hormonal stages. They don't account for the increased magnesium demands during the luteal phase. They don't reflect higher vitamin D needs in women with low baseline levels, darker skin tones, or limited sun exposure. They don't distinguish between the omega-3 needs of a 28-year-old and a 52-year-old woman going through the menopause transition.
This isn't a conspiracy. It's a calibration problem - one that starts with research design and ends with a label that wasn't built for you specifically.
What advocating for your own health actually looks like
This isn't about becoming your own doctor. It's about knowing where the gaps are so you can ask better questions.
Get specific with your testing.
A standard blood panel will often catch deficiencies only when they're severe. If you're experiencing persistent fatigue or poor concentration, it's worth requesting a full iron panel and vitamin D levels. These are often available through your GP, or through private testing if you're not getting traction.
Consider your life stage when thinking about supplementation.
Your needs at 22 are not the same as your needs at 38, 45, or 58. Hormonal transitions - including the perimenopausal window, which can begin years before periods stop, change the nutritional picture meaningfully. If you're unsure where to start, omega-3, vitamin D, and magnesium are three nutrients where women are disproportionately likely to be insufficient and where the research on benefit is robust.
Look at where your supplements come from.
Omega-3 from fish oil raises legitimate questions about sustainability, purity, and the presence of contaminants like heavy metals. Algae-based omega-3, the original source that fish accumulate DHA from, offers the same EPA and DHA without those concerns, making it a cleaner choice for anyone thinking carefully about what they're putting into their body.
Trust the pattern. If you've been told everything is fine but you don't feel fine, that's information. Advocate for investigation rather than reassurance.
A note for Endometriosis Awareness Month
March is also Endometriosis Awareness Month, and it felt important to name it here. Endometriosis affects an estimated 1 in 10 women in the UK(5), around 1.5 million people, and yet the average time from first symptoms to diagnosis is still 8 years. Eight years of pain being minimised, attributed to "bad periods," or simply not investigated properly.
It is, in many ways, a concentrated version of everything this piece is about: a condition that disproportionately affects women, that has been chronically underfunded and under-researched, and that too many people are still navigating largely alone. If you're one of them, or you know someone who is, Endometriosis UK is a good place to start: endometriosis-uk.org.
The health system wasn't built with women at the centre. That's not a criticism - it's a starting point. Because once you know where the gaps are, you can start asking better questions: of your doctor, of your test results, of the products you're putting into your body and the research behind them.
You don't have to be an expert in your own biology. But you do deserve health advice that was actually built for you. That's worth advocating for.
Sources:
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FDA 1977/1993 policy, confirmed via NEJM and womenshealth.gov.
Beery AK, Zucker I. Sex bias in neuroscience and biomedical research. Neurosci Biobehav Rev. 2011;35(3):565–72. - Wu J, Gale CP et al. European Heart Journal: Acute Cardiovascular Care, 2016. Also: bhf.org.uk/news-archive/2016/august/women-are-50-per-cent-more-likely-than-men-to-be-given-incorrect-diagnosis.
- Department of Health (1991). Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. HMSO. Or simply reference the NHS/BNF for a more accessible citation.
- Endometriosis UK Diagnosis Survey Report 2024 (endometriosis-uk.org/diagnosis-report)
- Koletzko B et al. Dietary fat intakes for pregnant and lactating women. British Journal of Nutrition, 2007.
- Rahbar N et al. Effect of omega-3 fatty acids on intensity of primary dysmenorrhea. International Journal of Gynecology & Obstetrics, 2012;117(1):45–
- Also: Zafari M et al. Comparison of the effect of fish oil and ibuprofen on treatment of severe pain in primary dysmenorrhea
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Mendelsohn ME, Karas RH. The protective effects of estrogen on the cardiovascular system. NEJM, 1999.