American tech entrepreneur and longevity researcher Bryan Johnson has once again sparked debate with an unusual revelation about his anti-ageing experiments. Johnson disclosed that he keeps a sample of his girlfriend’s menstrual blood stored in a freezer at -80°C as part of his ongoing health and longevity research.

The entrepreneur, who is widely known for spending millions of dollars annually on his mission to slow ageing, shared the information in a post on X. He revealed that approximately 10 ml of his girlfriend Kate Tolo’s menstrual blood is stored for scientific analysis.

The disclosure came a day after Johnson publicly questioned whether he had “taken this whole longevity thing too far.”

Why is Bryan Johnson storing menstrual blood?

Explaining the reason behind the practice, Johnson said menstrual blood could provide health insights that conventional blood tests cannot because it comes directly from the uterus.

According to him, analysing menstrual blood may help researchers identify uterine cells, immune cells and stem cells while also detecting environmental contaminants such as microplastics, PFAS (forever chemicals) and endocrine-disrupting chemicals.

Johnson described menstrual blood as an “underutilized” source of health information. He argued that it offers a non-invasive way to study the uterine environment without requiring surgical biopsies and can be collected during every menstrual cycle.

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Who is Bryan Johnson?

Bryan Johnson is an American entrepreneur best known for founding the online payments company Braintree, which was acquired by PayPal in 2013 for around $800 million.

In recent years, however, he has gained global attention for Project Blueprint, his ambitious longevity programme aimed at slowing biological ageing. Johnson follows a highly structured lifestyle that includes a plant-based diet, rigorous exercise, strict sleep routines, regular medical testing and various experimental health interventions.

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He frequently shares the results of his experiments on social media platforms, documenting hundreds of biological markers and exploring new approaches to extending human lifespan.

His latest revelation has once again ignited discussions online about the boundaries between scientific experimentation, preventive healthcare and unconventional longevity practices.

FAQs

Why does Bryan Johnson keep his girlfriend’s period blood in a freezer?

He says menstrual blood can provide valuable information about uterine health and help detect immune cells, microplastics, PFAS and other contaminants.

Who is Bryan Johnson?

Bryan Johnson is an American entrepreneur and founder of Project Blueprint, a longevity initiative focused on slowing ageing through data-driven health interventions.