Our Science

Backed by Years of Clinical Research

Clinical Research

On average, women lose 23.2 days per year to symptoms of PMS (low mood and anxiety) and menstrual pain.*

*M Schoep, et al., BMJ Open (2019).

The Facts

How the Brain Changes Throughout a Woman's Cycle

Throughout a woman's menstrual cycle, significant hormonal fluctuations occur, resulting in distinct changes in the brain's structure and function.

During the follicular phase, which encompasses the beginning of menstruation until ovulation, estrogen levels progressively rise. This rise in estrogen has been associated with enhanced cognitive abilities, particularly in verbal and social domains. Then, the ovulation phase occurs. This is the phase when estrogen and testosterone peak, and is typically a time of higher performance and libido.

Following ovulation, the luteal phase commences, characterised by increasing progesterone levels and declining estrogen levels. It's during this phase that many women experience premenstrual syndrome (PMS) symptoms. This is likely due to the effect of these hormonal shifts on neurotransmitters, such as serotonin and gamma-aminobutyric acid (GABA), which are critical for mood regulation and pain perception. However, why the brains of some women react to hormone changes in this debilitating way is not fully understood.

FireBand’s maximum benefits

The technology the Samphire Headband employs, transcranial Direct Current Stimulation (tDCS) has emerged as a promising way to combat mood and pain symptoms over the past 30 years. Unlike drug and hormone treatments, tDCS can strategically target areas such as the dorsolateral prefrontal cortex and the motor cortex, which play significant roles in mood regulation and pain management. With its ability to modulate brain activity non-invasively, tDCS is already established in alleviating conditions like depression, anxiety, and pain.

Backed by 8,000+ peer-reviewed research papers

Development and testing of a novel IoT consumer tDCS device for the treatment of primary dysmenorrhea

E Radyte, et al., Brain Stimulation Journal (January, 2023).

Read the paper

Evidence-Based Guidelines and Secondary Meta-Analysis for the Use of Transcranial Direct Current Stimulation in Neurological and Psychiatric Disorders

F Fregni, et al., International Journal of Neuropsychopharmacology (April, 2021).

Read the paper

Effects of tDCS for Treatment of Primary Dysmenorrhea: Preliminary Results of a Randomized Sham-Controlled Trial

R Pegado, et al., Pain Medicine (December, 2020).

Read the paper

To have a look at more papers that inspired the Samphire Headband, click here.

Let's take a closer look at the efficacy of tDCS when targeting common PMS symptoms.


Evidence-based guidelines published in 2021 by Fregni et al.** suggested that tDCS can significantly regulate mood. Specifically, the study summarised years of evidence and hundreds of studies, and concluded that tDCS is definitely effective (has class A evidence) for treating low mood in depressive disorders. The effect size of tDCS treatment was comparable with those reported for antidepressant drug treatment and repetitive transcranial magnetic stimulation in primary care. Their findings presented tDCS as a potential therapeutic tool for mood disorders, providing a non-invasive, side-effect-minimal alternative to pharmacological treatments.

Furthermore, In a 2020 study, Dutra et al. demonstrated that tDCS can reduce symptoms of anxiety in people with severe menstrual symptoms. They found that tDCS offered therapeutic benefits comparable to established treatments, suggesting that tDCS may be a promising non-pharmacological treatment alternative for managing anxiety in the pre-menstrual and the menstrual phases.


A double-blind sham-controlled randomized controlled trial by Mechsner et al. just this year (2023) found that anodal tDCS of the motor cortex has an analgesic effect on chronic pelvic pain in women with endometriosis. Their research indicated that tDCS might have potential as a non-invasive method for managing menstrual as well as chronic pelvic pain and other pain conditions, adding to its utility in the realm of pain management in the area of women’s health.

This builds on a range of studies, one of which is the 2020 Pegado et al. double-blind, sham-controlled clinical trial that indicated that tDCS over the primary motor cortex (M1) has significant effects in reducing menstrual pain in women with dysmenorrhea (severe menstrual pain that is not caused by a known underlying condition). This study presents tDCS as an effective, non-pharmacological approach to menstrual pain management.


A review by Jaberzadeh et al. (2022) recently established that tDCS can enhance maximal and sub-maximal aerobic performance (exercise efficiency) in healthy populations when stimulating the motor cortex (M1) like the Samphire Headband. Their findings showed not only the efficacy but also proposed a mechanism of action that would explain how the potentiation of the motor cortex leads to improved exercise capacity.

This has been tested with women in a randomised, placebo-controlled protocol during their menstrual period by Dutra et al. (2020), who found a significant improvement in endurance in women with menstrual symptoms after using tDCS for five days prior to their period. These findings suggested that tDCS could open new possibilities for non-pharmacological enhancements of focus and energy during vulnerable times of the month.

Meet our Scientific Advisory Board

Professor David Silbersweig
Professor David Silbersweig

Professor of Neuropsychiatry at Harvard and global PMDD neuroanatomy expert. He worked on one of the first pieces of research that showed that PMDD is a neurobiological condition, which laid the foundation for PMDD being recognised by the International Classification of Diseases.

Dr Marie-Christine Nizzi
Dr Marie-Christine Nizzi

Pyschologist and world-leading researcher on innovative clinical interventions. Currently the president of Harvard Alumni for Mental Health and is responsible for developing Samphire's cognitive science-based interventions.

Professor Rodrigo Pegado
Professor Rodrigo Pegado

World-leading chronic pain researcher from Universidade Federal do Rio Grande do Norte. He was the first person in the world to publish a paper on the topic of tDCS to treat pain in dysmenorrhea (menstrual pain).

Professor Maria Theresa Micussi
Professor Maria Theresa Micussi

Researcher from Universidade Federal do Rio Grande do Norte focused on neglected women's health conditions. Responsible for running Samphire's clinical trials.

Dr Sanjula Dhillon Singh
Dr Sanjula Dhillon Singh

Neurosurgeon focused on global public health. Also the founder of the podcast called ‘Science with Sanjula’ where she interviews world-leading scientists about big issues in global healthcare. She is helping Samphire translate our science into public impact.

Our Clinical Partners

Join our waitlist to be the first to hear about when our at-home Menstrual Neuromodulation Therapy wearable launches, early next year.