Why women's health is decades behind: the research gap

The women's health research gap is the distance between what medicine knows about men and what it knows about you.

It has a start date.

In 1977 the FDA issued guidance telling drug developers to exclude pregnant women, plus "women who are at risk of becoming pregnant," from Phase 1 studies. Women of childbearing age were to stay out of large trials until animal safety work was done. It is on the record in the Institute of Medicine's review of women and health research.

16 years of new drugs cleared without them.

So if a symptom of yours has ever been waved off, you have probably filed that under being difficult. Or unlucky. It was neither. The evidence was already thin before you walked in.

What is the women's health research gap?

A data deficit, built in three layers.

First, exclusion. Women were kept out of the earliest human trials by written policy.

Second, inclusion without analysis. A study can enroll women and never break the results out by sex, which leaves the question unanswered anyway.

Third, money. Funding follows attention, and attention followed the diseases that already had data.

Each layer got fixed on its own timeline. None of them got fixed backward. Everything approved under the old rules stayed approved.

Who decided women should be left out?

The FDA did, in writing, in 1977.

The document was called General Considerations for the Clinical Evaluation of Drugs. It said pregnant women and women at risk of becoming pregnant should be excluded from Phase 1. It said a woman of childbearing potential should stay out of large-scale trials until three segments of animal reproduction work were complete.

The stated motive was protection, in the long shadow of thalidomide.

The result was a generation of medicines whose first human data came almost entirely from men. Protection from research is still absence from research.

Who is the "70-kilogram man"?

A nickname for the standard body that medicine designs around.

You can read the real version yourself. Open the FDA's 2005 guidance on picking a first human dose, Estimating the Maximum Safe Starting Dose in Initial Clinical Trials. It converts animal doses with one figure: "Assumes 60 kg human." Sex appears nowhere in that math.

One body. One number. Everyone else gets rounded toward it.

Rounding is not harmless, and the size of the harm has been measured.

"The common practice of prescribing equal drug doses to women and men neglects sex differences in pharmacokinetics and dimorphisms in body weight, risks overmedication of women, and contributes to female-biased adverse drug reactions." — Zucker and Prendergast, Biology of Sex Differences, 2020 (PMID 32503637)

When did the rules actually change?

Twice, and slowly.

1993 was the first turn. The FDA withdrew the 1977 restriction and issued new guidance calling for women in early studies. Congress passed the NIH Revitalization Act the same year. It required women and minorities in NIH clinical research, and enough Phase 3 enrollment to analyze the differences. Both moves are documented in a 2016 review in Pharmacy Practice.

Being counted is not the same as being studied.

The second gap closed 23 years later. NIH began requiring researchers to consider sex as a biological variable for applications due on or after January 25, 2016. Its own Office of Research on Women's Health lays out that timeline in a 5-year progress report (PMID 31971851).

1977 to 2016. That is 39 years of medicine built the old way.

Where does the research money go?

Disproportionately to diseases that affect men.

A 2021 analysis in the Journal of Women's Health matched NIH funding against disease burden, measured in disability-adjusted life years. In nearly three-quarters of cases where a disease affects primarily one gender, the funding pattern favored males. Either the disease skews female and is underfunded, or it skews male and is overfunded.

The mismatch ran nearly twice as large for the male-favoring diseases.

"NIH applies a disproportionate share of its resources to diseases that affect primarily men, at the expense of those that affect primarily women." — Mirin, Journal of Women's Health, 2021 (PMID 33232627)

How long does a diagnosis take?

For endometriosis, an average of 6.7 years.

That figure comes from 1,418 women recruited at 16 clinics in 10 countries and published in Fertility and Sterility. The delay sat mostly in primary care, and it stretched to 8.3 years in systems where care was state-funded. See Nnoaham et al. (PMID 21718982).

Each affected woman also lost about 10.8 hours of work a week.

Read 6.7 years as time, not as a statistic. Roughly 80 periods spent being told this is normal, while the answer sat one referral away.

Do drug doses still get this wrong?

Yes, and there is a label to prove it.

In 2013 the FDA lowered the recommended bedtime dose of zolpidem for women from 10 mg to 5 mg, and from 12.5 mg to 6.25 mg for the extended-release form. The reason, in the agency's own words: "Zolpidem is eliminated from the body more slowly in women, so the drug can stay in their systems longer than it does in men." Read it on the FDA's zolpidem safety page.

The drug had been on the market since 1992.

It is not a one-off. Of 86 drugs with sex-specific data, 76 ran higher or cleared slower in women. We take that apart in dosed like a smaller man.

What can you actually do with this?

Four things, and none of them require a fight.

• Ask whether the dose was studied in women. A good clinician will tell you what the label says and what it does not.
• Date your symptoms. "Pelvic pain, 9 of the last 12 months" moves a chart. "It hurts sometimes" does not.
• Ask for a refusal in writing. If a test gets declined, request that the decision be noted. That one ask changes how carefully it gets made.
• File side effects instead of absorbing them. Reported reactions become evidence. Quiet ones become nothing at all.

You should not have to do any of this. It still works.

Where does fiber fit into any of this?

In one narrow, honest place.

The gap is not only in drug trials. It shows up in basic nutrition targets almost nobody hits. The recommendation for women aged 19 to 50 is 25 grams of fiber a day. Average US intake measured 16.2 grams. An estimated 95% of American adults and children fall short, per Quagliani and Felt-Gunderson in the American Journal of Lifestyle Medicine.

A known target, a measured shortfall, and no mystery. That is rare in this field.

Seya makes one product, a fiber gummy delivering about 5 grams of resistant tapioca fiber a day. That is roughly half the dose used in the larger fiber trials, so the honest claim is that fiber supports regularity. Nothing past that. The numbers are laid out in how much fiber women need per day and the fiber gap.

A gummy does not close a 39-year hole in the literature. It closes one number you can count at home.

Sudden changes in pain, bleeding, or digestion belong in a doctor's office, not a supplement aisle.

This article is general information, not medical advice. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Related reading: what happens to your gut at midlife, the luteal phase explained, and more from the Seya journal.

Frequently asked questions

Why is women's health research decades behind?

Because women were excluded from early drug trials by policy, and the policy lasted 16 years. A 1977 FDA guideline, General Considerations for the Clinical Evaluation of Drugs, directed that pregnant women and women at risk of becoming pregnant be excluded from Phase 1 studies. It also held women of childbearing potential out of large-scale trials until three segments of animal reproduction testing were complete.

The FDA reversed that position in 1993. NIH did not require sex to be considered as a biological variable until applications due on or after January 25, 2016. Drugs and guidelines established before those dates were built on the earlier standard.

When were women allowed into clinical trials?

1993 was the turning point. The FDA issued new guidance that year, withdrawing its 1977 restriction and asking for women in early-phase research. Congress passed the NIH Revitalization Act the same year. It required the inclusion of women and minorities in NIH-funded clinical research, plus enough Phase 3 enrollment to allow valid analysis of differences.

Inclusion alone did not settle the question. Trials could enroll women and still never report outcomes by sex. NIH did not require sex to be treated as a biological variable in the research it funds until January 25, 2016, according to its Office of Research on Women's Health.

How long does it take to diagnose endometriosis?

An average of 6.7 years. That number comes from a study of 1,418 premenopausal women, recruited at 16 clinical centers across 10 countries, published in Fertility and Sterility in 2011.

The delay fell principally in primary care and was longer, 8.3 years versus 5.5, in centers where women received predominantly state-funded health care. Delay increased with the number of pelvic symptoms reported. Each affected woman lost on average 10.8 hours of work per week, mainly through reduced effectiveness while working. The authors called for a higher index of suspicion so symptomatic women reach specialist assessment sooner.

What can I do about the research gap as a patient?

Ask whether the dose you were prescribed was studied in women, and whether the label carries sex-specific dosing. Bring dated specifics rather than general descriptions, since a symptom with a duration attached is easier to act on than one without. If a test you request is declined, ask that the decision be recorded in your chart.

Report side effects rather than tolerating them, because unreported reactions never enter the evidence base. Never start, stop, or adjust a prescription on your own.

Written and reviewed by the Seya Health Editorial Team. Every claim on this page is sourced to primary regulatory or peer-reviewed research, as of July 2026.

Related reading

• Fiber Intake by State: America's Fiber Gap, Mapped and Ranked (2026)