R Pegado et al., Effects of Transcranial Direct Current Stimulation for Treatment of Primary Dysmenorrhea: Preliminary Results of a Randomized Sham-Controlled Trial, Pain Medicine (2020) L Dutra et al., Modulating Anxiety and Functional Capacity with Anodal tDCS Over the Left Dorsolateral Prefrontal Cortex in Primary Dysmenorrhea, International Journal of Women's Health (2020). E Radyte et al., Development and testing of a novel IoT consumer tDCS device for the treatment of primary dysmenorrhea, Brain Stimulation (2023) E Radyte et al., Modelling and Preliminary Clinical Validation of Home-based Menstrual Neuromodulation Therapy, IEEE (2024) . Rodrigues et al., Clinical usability study of a home-based self-administration transcranial direct current stimulation for primary dysmenorrhea: A randomized controlled trial, PLOS One (2024).

Grounded in neuroscience.

Q: Endometriosis and Chronic Pelvic Pain

S Mechsner et al., Transcranial direct current stimulation to reduce chronic pelvic pain in endometriosis: Phase II Randomized Controlled Clinical Trial, Pain Medicine (2023) da Silva et al., Investigating the efficacy of transcranial direct current stimulation on chronic pain management in endometriosis patients: A randomized controlled trial protocol, PLoS On e (2024)

Q: Safety and the tDCS Mechanism

M Bikson et al., Safety of transcranial Direct Current Stimulation: Evidence Based Update 2016, Brain Stimulation (2016) Chase et al., Transcranial direct current stimulation: a roadmap for research, from mechanism of action to clinical implementation, Nature (2019) Yavari et al., Mechanisms of action of transcranial direct current stimulation, Interventional Psychiatry: Road to Novel Therapeutics (2024) Ko et al., Safety of Transcranial Direct Current Stimulation in Neurorehabilitation. Brain Neurorehabilitation (2021)

Q: PMDD, Mood and Mental Wellbeing

E Baehr et al., Premenstrual dysphoric disorder and changes in frontal alpha asymmetry, International Journal of Psychophysiology (2004) H Eccles et al., The association between premenstrual dysphoric disorder and depression: A systematic review, Journal of Affective Disorders Reports (2023) L Stiernam et al., Emotion-induced brain activation across the menstrual cycle in individuals with premenstrual dysphoric disorder and associations to serum levels of progesterone-derived neurosteroids, Translational Psychiatry (2023)

Built for PMS, Dysmenorrhea (menstrual pain), PMDD and Endometriosis symptoms.

Rooted in decades of research in neuromodulation, neuroendocrinology, and women's mental health.

Why the brain for women's health?

The brain is central to hormonal symptom expression — and too often overlooked.

Hormonal conditions like PMS, Dysmenorrhea, PMDD, and Endometriosis are often seen as physiological, but they deeply affect how the brain regulates:

- Mood and emotional reactivity
- Cognitive clarity and focus
- Motivation and energy
- Pain perception and resilience

The prefrontal cortex and limbic system — two regions sensitive to hormonal fluctuation — are directly implicated in these changes.

How does brain stimulation work?

tDCS: Targeted brain support without serious side effects.

Transcranial direct current stimulation (tDCS) uses a safe, painless electrical current to support the brain circuits affected by hormonal sensitivity.

Delivered through a wearable headband, tDCS gently stimulates key areas involved in mood, pain processing, and emotional regulation.

Why tDCS?

- Clinically validated in over 1,000 trials
- Used in clinical settings for nearly 30 years
- No serious or systemic side effects
- Portable and non-invasive
- Provides convenient at-home use

Safe, brain-first support - where it's needed most.

People experiencing reproductive and gynecological health conditions often share a common challenge: heightened sensitivity to hormonal changes that disrupt mood, cognition, and even pain processing.

Our research suggests:

- PMS and PMDD involve changes in prefrontal-limbic response to normal hormonal shifts;
- Dysmenorrhea (period pain) disrupts neural pain pathways and emotional coping; and
- Endometriosis is associated with chronic neuroinflammation affecting mood and cognitive clarity.

tDCS offers a safe, non-pharmacological way to support these circuits, especially in the days leading up to and during symptom flares.

Read more about our ISO13485 quality testing, and regulatory status as a Class IIa medical device in the European Union and United Kingdom.

The WIND Trial

In parternship with researchers from Harvard and the Federal University of Rio Grande do Norte, Samphire conducted the WIND trial (Women’s Interventional Neuromodulation for Dysmenorrheic Dysphoria), the largest study to date investigating the use of tDCS in people with PMS and Dysmenorrhea.

Key Findings

Participants with PMS and severe dysmenorrhea (menstrual pain) reported:
- Improved mood and emotional regulation, as well as clearer cognitive function.
- Pain relief that lasted across multiple cycles, with effects increasing over time.

Also Reported

44% of participants with PMS and dysmenorrhea also met the diagnostic criteria for PMDD. After one month of using Nettle:
- 100% of PMDD participants with extremely low mood saw an improvement to moderate or mild symptoms.
- The average mood improvement was 34%, increasing over time.
- 67% of all users experienced meaningful mood changes as early as their first cycle.

Trial Design

- Two-arm, randomized, placebo controlled.
- Five sessions of wearable at-home use of Nettle over one menstrual cycle.
- Building the first evidence linking brain stimulation to symptom relief in hormonally linked mental health conditions.

Trial Goals

- Measure changes in mood, cognitive clarity, and emotional regulation within a single month (Nettle comes with a 3-month returns policy to maximize the benefit you see!)
- Map user response across different phases of the menstrual cycle.
- Compare tDCS outcomes across different diagnoses and symptom severities.

What's next: Our ongoing trials.

We are a science & research-first team and continue running a range of public and private clinical trials to support the women's health research ecosystem. You can find some of our ongoing trials and research partnerships below.

Endometriosis: A study with the NHS and University College London

ENHANCE: A randomised, controlled trial for chronic pelvic pain

We’ve partnered with the NHS and University College London Hospital, where Professor Ertan Saridogan and his team are leading a randomized controlled trial on at-home tDCS for chronic pelvic pain in Endometriosis.

This is a major step forward in recognizing the brain’s role in persistent pain conditions — and expanding options for those who cannot tolerate hormonal or surgical solutions.

Learn more

PMDD: A study with Queen Mary University London

Relief without pharmacological intervention

We’re collaborating with QMUL on an independent academic trial focused solely on tDCS for PMDD. This study builds on WIND’s signal that brain stimulation can improve extremely low mood in PMDD without pharmacological intervention to provide novel, evidence-based solutions for this oft neglected population.