Period blood is often called "dirty". Yet this fluid is a biological marvel. Far from being mere waste, menstrual blood is a unique cocktail of cells, nutrients and… hope for the medicine of tomorrow.
What is it really made of? Why is it different from the blood running through your veins? And how might it one day treat incurable diseases? A deep dive into an unsuspected resource.
Table of contents
1- Composition: It's not "just" blood
If you analysed your menstrual flow under a microscope, you would find it is far more complex than a simple cut on your finger. It contains 4 major components:
- Blood: Less concentrated in haemoglobin and iron than venous blood, because it is "diluted" by the other fluids.
- Endometrium: Fragments of the uterine lining (dead cells) that shed away. This is what sometimes gives the flow a lumpy texture or produces clots.
- Secretions: Cervical mucus and vaginal secretions, which give the fluid its sometimes viscous texture (similar to egg white).
- Microbiome: Natural bacteria from the vaginal flora that travel along with the flow on its way out.
2- Menstrual blood vs venous blood: The comparison
Why are the texture and colour so different?
| Criterion | 🩸 Venous Blood (Blood test) | 🥀 Menstrual Blood (Period) |
|---|---|---|
| Composition | Pure blood cells. | Blood + Tissue + Mucus + Bacteria. |
| Clotting | Clots quickly on contact with air. | Contains natural anticoagulants (plasminogen) so it can flow freely without blocking the cervix. |
| Viscosity | Liquid and fluid. | Variable (liquid, viscous, clots). |
| pH | Neutral (7.4). | Similar (around 7.2), which temporarily raises the vagina's naturally acidic pH. |
3- The revolutionary discovery: MenSC cells
Long considered biological waste, menstrual blood changed status in 2007. Researchers discovered that it contained Mesenchymal Stem Cells (MenSC).
Why is this extraordinary?
Stem cells are "blank-slate cells" capable of transforming into any cell in the body (heart, liver, neuron…) to repair an organ. They are usually found in bone
marrow (a very painful extraction) or in the umbilical cord (only available once in a lifetime).
The advantage of menstrual blood:
It is an abundant, free, monthly and non-invasive source. Collection is painless (via a menstrual cup, for example) and raises no ethical
concerns. What's more, these cells multiply twice as fast as those from bone marrow!
4- Future: 10 diseases your period could help treat
MenSC (Menstrual Stem Cells) are currently being studied for the treatment of serious conditions. A 2019 scientific review (2) outlined the therapeutic prospects:
🧠 Brain & Nervous System
- Stroke: They could repair nerve damage.
- Alzheimer's disease: Potential for improving memory and learning.
🫀 Heart & Circulation
- Heart attack: Restoration of cardiac function after a cardiac event.
- Critical limb ischaemia: Rescuing limbs deprived of oxygen (avoiding amputation).
🍬 Metabolism & Organs
- Type 1 diabetes: Regeneration of pancreatic cells.
- Liver: Treatment of fibrosis and liver failure (as an alternative to transplant).
- Lungs: Repair of acute lung injury.
♀️ Gynaecology
- Endometriosis: MenSC could serve as a tool for early diagnosis (3).
- Ovarian cancer: Anti-tumour properties and regeneration.
- Asherman's syndrome: Repair of uterine adhesions (infertility).
- Duchenne muscular dystrophy: Muscle regeneration.
5- Conclusion: Time to change the way we see it
The next time someone tells you that periods are "dirty", tell them that this blood may hold the key to treating their heart or liver one day. Your period is not waste — it is an untapped vital resource.
(1) Cui CH et al., "Menstrual blood-derived cells confer human dystrophin expression...", Mol Biol Cell., 2007
(2) Chen L. et al., "The multi-functional roles of menstrual blood-derived stem cells", BMC, 2019
(3) Warren L.A. et al., "Analysis of menstrual effluent: diagnostic potential for endometriosis", Molecular Medicine, 2018
