Women were left out.
For decades, new medicines were tested mostly on men. Women were then given the same medicines anyway.
The result: women spend a quarter more of their lives in poor health than men.
World Economic Forum and McKinsey Health Institute, 2024 (a modelled estimate)
Why period blood is special
What science already knows makes it worth collecting.
It mostly stays liquid
When you cut your finger, the blood thickens and stops. Period blood mostly stays runny. Much of it has already clotted inside the womb, and the womb lining dissolved those clots again with its own enzymes. Small clots on heavy days are normal.
It comes from a tissue that heals without scars
Period blood comes from the lining of the womb. A deep cut on your knee leaves a scar. The womb lining breaks down and rebuilds itself up to about 400 times in a life, and it normally leaves no scar. No other tissue in the adult body does this as a normal routine.
It carries healing signals
The womb starts repairing itself while the period is still going on. Period fluid contains proteins that help cells move in and close a wound. In early research, it even helped skin wounds heal, in lab dishes and in pigs. These were lab and animal tests. Nobody uses it as a medicine.
It is a window into the womb
Period blood carries living cells from inside the womb, including special immune cells that are different from those in ordinary blood. Getting these cells any other way usually means a doctor taking a small tissue sample (a biopsy), which can be painful. Period blood brings them out every month.
Better medicine starts with data. For periods, there is almost none.
Research can only answer questions it has data for. Periods have barely been measured.
* As far as we know, from published studies and trial registers. Details and all sources are on our science page.
The world's largest bank of menstrual blood.
Thousands of women. A sample from every period, year after year. Kept safe, controlled by the women who give them, and open to research that helps women.
Every month, period blood is thrown away. It could help research.
Period blood contains cells from the lining of the womb. Collected over many months, it becomes knowledge that has never existed. Building it is our job, together, for the good of all women.
No one will close this gap for us. So we do it together.
Around the world, women, scientists and doctors are starting to close the gap. We want to bring them together, and to give every woman a way to take part.
Every woman who takes part, supports or simply spreads the word helps build the data women have been missing.
Simple for you. Useful for research.
We will start with a small group of women. Details follow once the study is approved.
Your sample. Your say.
The samples are looked after by a non-profit association. The women who take part have a say in what they are used for.
Why I started this
“AI is about to change medicine, but it can only learn from the data that exists. For women, most of that data was never collected. So AI learns from men.
I've spent years in biotech and finance, watching where the money and data go. Women's health gets neither. No one has fixed this because it isn't easy, but it has to be done.
I can't promise a cure for any disease. But a woman who gives samples today and falls ill ten years from now may find that what we stored helps find answers for women like her, and for the generations after her. And every sample makes the world a little better.
What I can promise is how we do it: as a non-profit, with medical researchers, funded by grants, donors and partners. What we learn belongs to everyone. And no woman's data is ever used without her say.
Women have been promised a lot. Let's gift our daughters a world where medicine knows their bodies.”
Join the movement.
Everyone who joins before the first study starts is a founding member: one of the first to stand behind the movement.
The first founding members will appear here.
Doctor, researcher, pharmacy or supporter? Write to us: hello@period.foundation