This CEO keeps his girlfriend’s period blood in the freezer. Here’s why
An American entrepreneur has revealed that he keeps his girlfriend’s period blood in the freezer as part of his longevity and health research
Bryan Johnson has revealed that he keeps his girlfriend’s period blood in the freezer as part of his longevity and health research. The tech entrepreneur, who is best known for spending millions of dollars every year in his quest to slow down aging, revealed the startling fact in an X post this morning.

“Kate’s period blood is in my -80 °C freezer,” he wrote, with Kate referring to his girlfriend Kate Tolo — a 30-year-old Australian-Bosnian biohacker.
The California-based founder and CEO of Project Blueprint added that he keeps around 10 ml of his girlfriend’s period blood in his freezer. This post comes just a day after he publicly wondered whether he had “taken this whole longevity thing too far”.
Why is there blood in the freezer?
In a follow-up post, Bryan Johnson went into further detail about why he keeps his girlfriend’s menstrual blood in the freezer.
Johnson argued that menstrual blood could provide health information that a standard blood test could not because it came directly from the uterus. He said analysing it could help detect uterine cells, immune and stem cells, as well as contaminants such as microplastics, PFAS (‘forever chemicals’) and endocrine-disrupting chemicals.
“Menstrual blood is valuable and underutilized,” he claimed. “We collected to look for diseased tissue, measure microplastics, measure endocrine disruptors, measure PFAS.”
“It’s a non-invasive look into the uterus,” he claimed, adding: “This is great because you get the data without surgical biopsy, it can be repeated every single cycle, and it measures the uterine environment directly instead of inferring it from a standard blood draw.”
Who is Bryan Johnson?
Bryan Johnson is an American tech entrepreneur who founded the online payments company Braintree, which was acquired by PayPal in 2013 for about $800 million. In recent years, he has become widely known not for his business ventures but for his pursuit of longevity, documenting his efforts to slow aging through a project he calls Blueprint.
Johnson follows an unusually strict health regimen that centres on a carefully controlled plant-based diet, regular exercise, consistent sleep, extensive medical testing and a range of supplements and treatments.
He tracks hundreds of biological markers, undergoes frequent scans and blood tests, and often experiments with new health interventions, sharing the results publicly.
(Also read: Bryan Johnson says he may have gone ‘too far’ with longevity experiment)
ABOUT THE AUTHORSanya JainSanya Jain is an Assistant Editor with Hindustan Times Digital. She has nearly a decade of experience in covering offbeat stories that speak to the everyday experience - from viral videos to human interest copies that spark conversation. Her interests stretch across business, pop culture, social media trends, entertainment and global affairs. Before joining Hindustan Times, Sanya spent two years with Moneycontrol and five years with NDTV. She holds an undergraduate degree in English literature from St Stephen’s College, Delhi, and a master’s in journalism from the Xavier Institute of Communications, Mumbai. Sanya has a sharp eye for spotting emerging trends and looking for newsworthy angles to elevate viral posts into meaningful narratives. She was the first one, for example, to cover Narayana Murthy’s remark on 70-hour work weeks that sparked a national conversation. She is equally at ease writing about business leaders as about the common man, about issues of national importance and memes that amuse social media. Sanya enjoys speaking with content creators, newsmakers and entrepreneurs to transform everyday moments into engaging, slice-of-life stories that resonate with readers. When she is not working, Sanya can be found curled up with a good book. Born and raised in Lucknow, she has spent the last several years in Delhi. She is deeply interested in animal welfare and now spends a lot of her time running after her destructive orange cat.Read More

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