16 January 2026
Beyond the Cycle: Hystelica’s Call for Hormone-Informed Psychedelic Medicine in Women
By: Grace Blest-Hopley, Ph.D.
MAPS Bulletin: Volume XXXVI
As a neuroscientist and founder of Hystelica, my path into women’s health and psychedelic research was both scientific and deeply personal. My curiosity about the brain began in medical science, but became urgent after witnessing both friends and myself struggle with mental health conditions and poorly understood hormonal symptoms. After years spent studying neuroscience, and even serving as one of the first women in my British Army regiment, I was struck by how often women’s unique biology was invisible in research, medical care, and society. This realization — and my own journey using science, psychedelic experiences, and community to make sense of complex symptoms — led me to create Hystelica. Women live within a cycle that profoundly influences mood, brain chemistry, and perception — yet in most psychedelic research protocols, this cycle is either ignored or treated as a nuisance. Our mission is to make women’s bodies and histories central to psychedelic science, combining lived experience, research, and education to drive change for women everywhere. My goal here is simple: to highlight why centering women’s biology in psychedelic research is not optional. It is the foundation for both safety and genuine therapeutic innovation.
Why Ignoring Hormones is a Risk
The influence of estradiol (E2) and progesterone (P4) on neurotransmitter systems is central to understanding psychedelic pharmacology. These hormones directly shape serotonin, dopamine, GABA, and glutamate pathways—the very same neural networks that psychedelics act upon to produce their effects. Throughout the menstrual cycle, changes in 5-HT2A receptor density and signaling further alter how these systems function. This means the same dose of psilocybin at ovulation may feel radically different premenstrually. At Hystelica we have now been able to collect and analyze data from our Survey of Female Psychedelics Use that begins to uncover the effect of cycle on the subjective experience of the psychedelics.
Ignoring these fluctuations risks more than unpredictable trip reports. It risks misinterpreting clinical outcomes and undermining what could be precise, personalized medicine. Women living with premenstrual dysphoric disorder (PMDD), perimenopausal volatility, or hormone-linked depression may respond very differently to psychedelic therapies depending on their cycle stage. Accounting for those differences is not an inconvenience – it is the key to unlocking both safety and effectiveness.
Animal research offers early proof. Female rodents treated with psychedelics often show distinct cognitive and behavioral changes compared to males (Shadani et al., 2024). These findings suggest meaningful sex-linked differences, yet most mechanistic psychedelic work continues to default to male animals, and the majority of clinical trials underrepresent women – or even exclude cycling women entirely. As I argued with my colleague in our recent paper (Cohen & Blest-Hopley, 2025), this builds research foundations on unsteady ground.
If psychedelics are to live up to their promise, sex must stop being treated as a confounding variable and start being recognized as a defining one.
The Potential of Timing and Targeted Treatment
With the right approach, the very hormonal shifts that complicate psychedelic outcomes could be harnessed as therapeutic advantages. Aligning treatments with phases of the cycle may improve outcomes, reduce risks, and ensure women receive care tailored to their biology.
Potential therapeutic avenues include:
- PMDD and PMS (Premenstrual syndrome): Early data suggest psilocybin could dampen the cyclical emotional volatility of PMDD by modulating serotonin networks aligned with estradiol fluctuations.
- Perinatal applications: Postnatal depression — where we already have promising Phase 2 data.
- Chronic pain in women: Psychedelics show potential in resetting dysfunctional pain pathways. Given the higher incidence of autoimmune and chronic pain conditions among women, this area represents a critical focus for advancing healthcare and therapeutic interventions.
- Menopause and ageing: Both psychedelic therapy and estrogen have shown neuroprotective effects. Used together, they could offer innovative strategies to preserve brain health and reduce cognitive decline, while also alleviating mood symptoms of menopause.
Though evidence remains sparse and largely anecdotal, intriguing case studies have sparked curiosity about the impact of classic psychedelics on menstrual function. Reports include women experiencing resumed periods after amenorrhea, earlier-than-expected menstrual onset after psychedelic use, and regulation of previously irregular cycles (Gukasyan & Narayan, 2024). While these cases suggest a real biological interplay, further controlled research is needed to clarify the extent and mechanisms of psychedelics’ influence on menstrual health.
By combining psychedelic pharmacology with an understanding of ovarian hormone biology, we could not only improve safety but potentially develop new, women-specific treatments.
Research and Cultural Knowledge
To realize this vision, research must evolve beyond a blanket, one-size-fits-all approach. We urgently need:
- Cycle-conscious trials: Integrating tracking of menstrual cycle phases, hormonal assays, and life-stage variables (e.g., perimenopause, postnatal states).
- Women-focused conditions: Dedicated trials for PMDD, menopause, and chronic pain syndromes.
- Mechanistic clarity: Mapping estradiol–serotonin–psychedelic interactions, and integrating biomarkers of menstrual and reproductive health into study designs.
- Holistic frameworks: Trials that account for the psychological and sociocultural realities of womanhood, not just the biology.
At Hystelica, we’ve begun this work. Our recent surveys are the first to shine light on how psychedelics intersect with menstruation, postpartum, and perimenopausal stages. Soon, we’ll share early data on cycle-linked differences in experience and outcomes. These insights, though preliminary, already show the importance of bringing these questions into mainstream psychedelic science.
Cultural knowledge also points us forward. In some Amazonian traditions, women are excluded from ayahuasca ceremonies during menstruation (Fotiou 2014). While often framed in spiritual terms, such practices may stem from centuries-old observations of altered psychedelic responses during this time. Rather than dismissing such traditions, we can learn from them — enriching empirical research with intergenerational wisdom.
Call to Action: Seizing the Opportunity
The psychedelic field now faces a choice. Do we continue building clinical evidence on under-researched populations – risking repeating medicine’s historic neglect of women? Or do we seize the moment to build something better: research that integrates women’s biology, psychology, and lived experience from the very start?
Supporting this evolution means supporting organizations like Hystelica, whose mission is to lead a wave of female-centered psychedelic research. That can mean following our work, participating in our studies, or funding our efforts. The stakes are high:
- Adverse reactions to licensed medicines are consistently higher in women, precisely because trials have not accounted for female biology.
- The same oversight in psychedelics could prove disastrous, worsening treatment inequities and eroding trust.
- By contrast, including women fully and equitably promises profound rewards – not just safer treatments, but a paradigm shift in how we understand women’s health.
By centering female biology in psychedelic research, we don’t just create better psychedelic medicine. We create a movement towards healthcare equity, recognition, and respect. This is not secondary. This is the paradigm shift. Psychedelics, after all, are about opening our eyes. Let us not stay blind to women.
References
- Cohen, Z. Z., & Blest-Hopley, G. (2025). Females in Psychedelic Research: A Perspective for Advancing Research and Practice. ACS Pharmacology & Translational Science. Advance online publication. https://doi.org/10.1021/acsptsci.5c00255
- Gukasyan, N., & Narayan, S. K. (2024). Menstrual Changes and Reversal of Amenorrhea Induced by Classic Psychedelics: A Case Series. Journal of Psychoactive Drugs, 56(1), 50-55. https://doi.org/10.1080/02791072.2024.XXXXX (DOI placeholder)
- Shadani, S., Conn, K., Andrews, Z. B., & Foldi, C. J. (2024). Potential Differences in Psychedelic Actions Based on Biological Sex. Endocrinology, 165(8), bqae083. https://doi.org/10.1210/endocr/bqae083
- Fotiou E. On the uneasiness of tourism: Considerations on shamanic tourism in Western Amazonia. In: Labate BC, Cavnar C, eds. Ayahuasca Shamanism in the Amazon and beyond. New York: Oxford University Press; 2014:159-181. doi:10.1093/acprof: oso/9780199341191.003.0008
Grace Blest-Hopley, Ph.D.
Dr. Grace Blest-Hopley is a Neuroscientist with 10 years of experience researching cannabis, cannabinoids, and psychedelics. She is the founder of Hystelica – the first research organisation in the world focused on understanding women’s biology for safe and effective psychedelic use. Grace currently serves as the Chief Scientific Officer at NWPharma Tech and is also the Research Director at Heroic Hearts Project, a charity connecting military veterans with mental trauma to psychedelic therapy options: ayahuasca, psilocybin, and ketamine.
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