A UK-based menstrual health startup, Joii, has launched the world’s first AI-powered app capable of measuring period blood volume, marking a major breakthrough in women’s health technology. The Joii Period Evaluation app aims to transform how people with periods monitor their menstrual health by turning subjective experiences into clinically valuable data.
Registered as a Class I medical device in the UK, the innovation represents a significant step forward in tackling one of the most under-researched and overlooked areas of women’s healthcare. Despite the prevalence of menstrual health conditions, diagnosis rates remain low and delayed. Research shows that one in three people with periods experience heavy bleeding, while nearly half of those with endometriosis visit their GP more than ten times before receiving a diagnosis. Alarmingly, 78% report being told they were “making a fuss about nothing.”
The Joii system combines AI technology with specially designed pads to provide an instant, objective measurement of blood loss and clot size. Users scan their pad with their phone, and the app provides clinically precise data within seconds.
“We already count our steps, monitor our sleep, and track our heart rate,” said Justyna Strzeszynska, Founder of Joii. “Measuring blood loss is simply the next step to better understanding our bodies and demanding the care we deserve. We want every woman to have proof, not just pain.”
Doctors typically use thresholds such as 80ml of blood loss per cycle or clots larger than 2.5cm to determine whether a patient may have a menstrual disorder. Until now, however, there has been no practical method for individuals to measure these metrics accurately. Joii’s technology bridges that gap, giving users tangible data to support discussions with healthcare professionals.
The app goes beyond measuring blood volume. It allows users to log and monitor a range of menstrual symptoms, including pelvic pain, fatigue, cravings, and brain fog, which are often associated with conditions such as fibroids, adenomyosis, PCOS, and endometriosis. The data helps identify patterns and red flags while improving communication between patients and doctors.
In addition to measurement tools, the app provides cycle tracking, appointment notes, educational materials, and personalised health insights. It is designed to help users build a more complete picture of their menstrual health.
A five-month feasibility study carried out with the University of Bradford and funded by Innovate UK highlighted the app’s potential. Findings showed that 88% of users said it improved how they communicate period volume with their GP, and 52% reported better understanding of their menstrual health. In a separate clinical study, 93% of GPs said the app could aid diagnosis of heavy bleeding, while 80% believed it would help guide treatment plans.
To use the system, users purchase Joii Evaluation Pads, made from organic cotton and biodegradable materials, then download the free app from the Apple App Store or Google Play. Once scanned, the app provides instant data on flow volume and clot size, helping users track changes and share information with clinicians.
The Joii Period Evaluation app is now available for free on iOS and Android, with the evaluation pads available for purchase in the UK via the Joii online store.
