Kate Tolo will start her period any minute now.
Biohacker Bryan Johnson has been tracking the milestone for 34 straight days, a feat he describes as the most measured menstrual cycle in history.
The data has poured in from an array of sensors and tests: 408 minutes of brain activity, more than 10,000 blood glucose readings, nearly 49,000 core body temperature measurements and 136 full-body photos.
In total, the couple has logged 14 million data points on her cycle.
Johnson shared the update on X on Aug. 30, posting a photo and a detailed list of what is being measured.
It includes ingested pills for core temperature, pain thresholds, grip strength, vaginal microbiome swabs, cervical mucus checks, DNA methylation, oral and stool microbiomes, hormone metabolites in urine, resting metabolic rate and even a “techno-tampon” device.
“proud of @_katetolo for becoming the world’s most measured woman,”
Johnson wrote.
Kate Tolo is the girlfriend of tech entrepreneur and longevity biohacker Bryan Johnson.
Johnson, 48, is the founder of Immortals and Blueprint, companies focused on extending human lifespan through AI and biotech.
He also co-founded Kernel, which develops brain-monitoring devices, and Braintree, the digital payments platform he sold to PayPal in 2014 for more than $800 million.
Tolo, 30, has a background in fashion and was introduced to Johnson in late 2020.
The pair met through the tech scene in Los Angeles and began dating shortly after.
Johnson has described their connection as similar to the partnership of John Adams and Abigail Adams, calling it a “puzzle piece” fit that helped him move past his own guarded past.
In December 2025 Johnson posted a long thread announcing Tolo as his girlfriend and referencing their shared goal of living longer.
The couple has not married and Johnson has said he has never slept in the same bed as Tolo, citing research on separate sleep for better health.
Early in 2026 the pair began an intensive protocol for Tolo’s menstrual cycle, with Johnson spending around $2 million per year on the effort.
In the spring they diagnosed Tolo with endometriosis, polycystic ovary syndrome and adenomyosis in just 42 days — a process that normally takes an average of 6.6 years.
Diagnosis came through non-invasive imaging and blood work, confirmed across three modalities.
Tolo’s period blood has been collected in a cup and stored in Johnson’s -80°C freezer, about 10 milliliters so far.
Johnson and Tolo have shared the protocol publicly, including a July report listing 88 daily tasks for Tolo and a medical team of 12 overseeing it.
They aim to make the data available for free to advance research on female health.
Johnson’s post about the 34-day cycle drew tens of millions of views, with reactions ranging from praise for the transparency to questions about the personal and financial commitment involved.
The couple continues to work together on longevity projects, with Johnson describing Tolo’s protocol as “better than mine” in speed and detail.
The tracking remains ongoing, with Johnson saying Tolo’s period could begin at any moment.
