Hormones and Drugs: How the Pharmaceutical Industry has Failed Women

The Problem

Have you ever felt that your medication simply isn’t working as well as it usually does on a particular day? If you have, there may be a predictable, physiological reason for it. Drug metabolism, absorption, and elimination rates often shift dramatically with hormone levels. This is especially true of sex hormones such as estrogen and testosterone. These hormones can impact the transporters, enzymes, and receptors that are involved in how the body reacts to a medication, and thus their varying levels may change the effects of the medication¹. While everybody reacts to medications slightly differently, the impact of sex hormones makes this difference especially pronounced when we compare men and women. 

Artwork by Shea Davis

Sex hormone levels change throughout everyone's lifetime; they increase at puberty and decrease with age. Such changes are more severe and visible in women who begin menstruation when hormone levels rise and menopause when they fall, with pregnancy also dramatically altering hormone levels. Additionally, a woman’s hormone levels change on essentially a daily basis as she moves through the different stages of menstruation. This can have a significant impact on the effectiveness of medications as the month goes on, something men don’t have to worry about because their hormone cycle is daily rather than monthly. I, for example, find my ADHD medication doesn’t work as well during the luteal phase of my menstrual cycle. This is likely a result of how estrogen and progesterone impact dopamine receptors in the brain³.

Medication efficacy, or how well a drug works, thus may change for women throughout the month and throughout their lifetime due to corresponding hormonal fluctuations. Yet, the basis and impact of such changes are strikingly under-researched. This has led to many women struggling with medication management and experiencing adverse reactions disproportionately. Specifically, women are almost twice as likely to have adverse side effects and 1.6 times as likely to have purely adverse reactions to medications when compared to men^1,2. Predictably, this causes a host of medical problems for women, such as decreased medical adherence, discomfort, illness, and even death. The impact of hormone differences on drug efficacy is only beginning to be investigated, but such work is critical to improving women’s health.

The History

Women have historically been excluded or underrepresented in clinical drug trials. The prevailing belief was that women's hormonal cycles made them difficult subjects, which led  the pharmaceutical industry to primarily use men instead¹. This assumption that women’s hormones are “too complicated” highlights a critical issue: from the very beginning scientists realized that hormones can significantly influence how a medication functions. Yet, instead of addressing and exploring these complexities, they overlooked them and claimed that the medication would affect women in the same way it had affected the men in their trials. While significant strides have been made since the days of overtly sexist practices, the journey toward understanding the intricate relationship between hormones and pharmacology is far from complete. 

Artwork by Shea Davis

The FDA first began intervening in women’s participation in clinical trials in 1977. However, the guideline stated women of reproductive potential should be excluded from participating in early phase clinical research. The guideline was a response to the thalidomide crisis, a time when thousands of women took thalidomide to alleviate their pregnancy-related morning sickness and unfortunately many gave birth to infants with various birth defects as a result. While the FDA's response was certainly warranted, it had the problematic consequence of excluding most women of childbearing age from medical research and once again leading to male dominated studies. Years later, in 1986, progress was made with an NIH advisory committee recommending women be included in medical research studies and in 1993 the FDA followed suit, officially mandating the inclusion of women in research⁴. While this initially seems sufficient, a 2009 study found most pharmaceutical studies were only 37% women and researchers were not analyzing data differences between genders, which obscures any data relating to how the medication could impact women differently¹.

Potential Solutions

Researchers into how fluctuating hormone levels change the way specific medications work is critical to improving women’s health. We have seen the beginning of this with studies identifying medications shown to be particularly sensitive to hormone changes. Additional research on the mechanism of how sex hormones cause changes in drug reactions and efficacy should be pursued. An understanding of why medications change with hormones is essential to making informed improvements for women taking pharmaceutical drugs. 

Ultimately, personalized dosing based on individual fluctuating hormone levels should be explored as a means of enhancing treatment outcomes for women². This could reduce adverse reactions and help women receive consistent, predictable treatment. Such a proposal is complex, but if we can determine when individuals experience changes in metabolism, absorption, and elimination of a specific drug due to monthly hormonal changes, we can adjust dosages accordingly⁵. Menstrual cycle-dependent pharmacological care has the potential to optimize health outcomes for women everywhere. We are just beginning to investigate this fascinating topic, but with time and effort, it is possible to get women the pharmaceutical care they deserve.

Citations

1. Moyer AM, Matey ET, Miller VM. Individualized medicine: Sex, hormones, genetics, and adverse drug reactions [Internet]. U.S. National Library of Medicine; 2019 [cited 2025 Nov 17]. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6897337/

2. Bosch EL. The influence of female sex and estrogens on drug pharmacokinetics: What is the evidence? [Internet]. 2025 [cited 2025 Nov 30]. Available from: https://www.tandfonline.com/doi/full/10.1080/17425255.2025.2481891

3. 1. de Jong M, Wynchank DSMR, van Andel E, Beekman ATF, Kooij JJS. Female-specific pharmacotherapy in ADHD: Premenstrual adjustment of psychostimulant dosage [Internet]. U.S. National Library of Medicine; 2023 [cited 2025 Nov 30]. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC10751335/

4. Balch B. Why we know so little about women’s health [Internet]. 2024 [cited 2025 Nov 17]. Available from: https://www.aamc.org/news/why-we-know-so-little-about-women-s-health

5. Yum SK, Yum SY, Kim T. The problem of medicating women like the men: Conceptual discussion of menstrual cycle-dependent psychopharmacology [Internet]. U.S. National Library of Medicine; 2019 [cited 2025 Nov 30]. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC7032965/