Why Does Sex Matter in Supplement and Drug Research?

For decades, drug and supplement research was built almost entirely around male physiology, and a standard dose "tested on men" does not automatically work the same way in a woman's body. Women are frequently exposed to higher blood concentrations and longer elimination times than men at the same dose, which contributes to more frequent adverse reactions. Hormones like progesterone also shift how a woman's stress and metabolic systems respond, in ways that simply are not present in male-only research models. "Built for women" is not a marketing phrase. It is a direct response to a research gap that is only now being corrected.

The research gap nobody told you about

Women were largely excluded from clinical and preclinical research for most of the 20th century. A review of sex representation in biomedical research found that even after policies changed, analysis of outcomes by sex remains infrequent, meaning studies may include women but still fail to report whether results actually differ by sex. The NIH's own Office of Research on Women's Health was not established until 1990, specifically because so much clinical decision-making for women had been based on findings from studies of men, without evidence that those findings actually applied.

Why a dose "tested on men" does not automatically work the same in a woman's body

This is not an abstract concern. Differences in body composition, metabolism, and hormone cycling mean that a standard dose calibrated to average male physiology can behave differently once it reaches a woman's bloodstream, often resulting in higher exposure and a longer half-life for a given compound. That gap is a major reason adverse drug reaction rates have historically run higher in women, and it is part of why formulation, not just dosage, matters.

Your hormones change how your body responds, even to nutrients

The hypothalamic-pituitary-adrenal (HPA) axis, the body's central stress response system, shows measurable sex differences in reactivity. Research using a standardized social stress test found that men showed a more robust HPA axis stress response than women, and that progesterone levels were associated with a dampened cortisol and ACTH response in women specifically, a pattern that is simply unavailable to researchers studying male-only models.

Even nutrient intake shifts with the menstrual cycle. An NIH-funded cohort, the BioCycle study, found that total protein intake, animal protein intake, and food cravings were all significantly higher during the luteal phase compared with the periovulatory phase, independent of whether the cycle was ovulatory. A body that is cycling through these hormonal shifts every month is not the same baseline that most legacy nutrition and supplement research was built around.

"The FDA does not regulate dietary supplements. So making sure that whatever you're taking is being made by a reputable organization is really important."

— Dr. Jummy Amuwo, Pharm.D., MPH, BCPS, Clinical Pharmacist and Board Certified Pharmacotherapy Specialist

What it looks like to formulate around female physiology instead of around it

Our cortisol support supplement, formulated to support a healthy stress response and a balanced mood, with 300 milligrams of organic ashwagandha, chamomile, and a full B-vitamin complex, was built with these sex-based differences in stress physiology in mind rather than adapted from a general, male-normed stress formula.† Pair this with our clean-label prenatal with 5-MTHF and iron bisglycinate, a 22-nutrient formula built specifically around the physiological demands of pregnancy, preconception, and breastfeeding, not adapted from a general multivitamin.† Total Prenatal requires the pregnancy and breastfeeding provider consultation disclaimer: always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition.

"Pink Stork is more than a business, it's a calling rooted in faith and love. We formulate for the body women actually have, not the one research has defaulted to for a hundred years."

— Amy Suzanne Upchurch, Founder and CEO of Pink Stork

What to ask about any supplement or medication going forward

You do not need a science background to ask good questions. When starting any new supplement or medication, it is reasonable to ask your provider or pharmacist whether the dosing was studied in women specifically, whether your cycle phase could affect how it works, and whether the formulation accounts for differences beyond simple body weight. If you are curious how your own cycle maps onto these patterns day to day, our piece on whether a wearable can really tell you where you are in your cycle is a good next read, and if you are building a prenatal routine, our 15 questions to ask at your first prenatal appointment covers related ground.

Frequently asked questions

Does this mean supplements made for men are unsafe for women?

Not necessarily unsafe, but potentially less optimized. The concern is less about safety in a narrow sense and more about whether dosing, ingredient ratios, and timing were ever studied with female physiology in mind.

Why does the menstrual cycle affect how supplements work?

Hormone levels, metabolism, and even nutrient cravings shift predictably across the menstrual cycle. Research like the NIH BioCycle study shows measurable differences in nutrient intake and appetite between cycle phases, which is part of why a one-size-fits-all approach misses something.

When did research start requiring women to be included in clinical trials?

The NIH established its Office of Research on Women's Health in 1990 and strengthened inclusion requirements through the 1993 NIH Revitalization Act, but meaningful sex-based analysis of outcomes is still inconsistent across many fields of research today.

What should I ask my pharmacist about a new supplement?

Ask whether the dosing was studied in women, whether it interacts with anything else you are taking, and whether the manufacturer does third-party testing, since dietary supplements are not FDA-regulated the way medications are.

† 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. Always consult your healthcare provider before starting any new supplement, especially during pregnancy, breastfeeding, or while managing a medical condition. Keep out of reach of children.