Weather 
Forget love letters. Bryan Johnson is saving something a little more personal from Kate Tolo.
The tech entrepreneur turned biohacker has built a following by turning his quest to cheat death into a social media spectacle, documenting everything from his bodily functions to bedroom habits in pursuit of longevity.
His girlfriend is increasingly becoming part of the show — and the couple’s latest science project is being kept on ice.
“Kate’s period blood is in my -80 °C freezer,” Johnson recently wrote on X. “Around 10 mL.”
The crimson keepsake, according to the Blueprint co-founder, is “valuable and underutilized.”
“It’s a non-invasive look into the uterus,” Johnson wrote. “She collected the blood during her last cycle.”
Johnson says the sample will be used to search for signs of diseased tissue, microplastics, endocrine disruptors and so-called “forever chemicals” known as PFAS, which can accumulate in the body over time.
“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,” Johnson explained.
The revelation comes as Tolo, 30, undergoes an intensive 100-day project to collect 14 million data points on her menstrual cycle.
Johnson recently shared a glimpse into her daily routine, which is mapped out minute by minute and includes spitting into collection tubes, swabbing her cheek and using a high-tech tampon for deeper health tracking.
The $2.6 million undertaking aims to help address gaps in medical research around female reproductive health.
“I’m really doing it because I think that this is our path toward women being understood in the world and being seen,” Tolo told The Wall Street Journal in July.
The effort follows Tolo’s diagnosis with endometriosis, a painful condition in which tissue grows outside the uterus, causing chronic pain, inflammation and scarring.
“This affects at least 1 in 10 women, likely more,” Johnson wrote on X in May alongside a photo of himself watching Tolo’s ultrasound during a gynecological exam.
“Typically women live with endometriosis for 7-10 years before being diagnosed.”
Tolo, who has said she suffered from severe pain during her periods for years, has also been diagnosed with polyendocrine metabolic ovarian syndrome, previously known as polycystic ovary syndrome, or PCOS.
Johnson has also publicly documented his own health struggles, revealing earlier this summer that he had been diagnosed with autoimmune gastritis, an incurable chronic condition in which the immune system attacks acid-producing cells in the stomach.
“My sincere goal is to try and heal the sick. With AI and biotech, we no longer have to concede to disease. We don’t need to wait for big, billion-dollar companies to do it for us,” the California-based venture capitalist wrote in response to critics on his latest post.
“I’ll cure my AIG and we will cure Kate’s endo, and then make the same available to others.”
Along the way, Johnson has also found time to tout one of Tolo’s most personal data points.
In May, the biohacker declared that his better half had the “top 1% of all vaginas,” citing results from her Tiny Health vaginal health test.
“Her sample is dominated by the single most protective bacterial species a vagina can host (Lactobacillus crispatus),” Johnson told his more than one million followers on X.
“Only about 25-30% of reproductive-age women globally are L. crispatus-dominant, and dominant usually means above 50%. Kate is at 98.7%,” he added.
Johnson, who once called himself an “impossible partner” because of his ultra-rigid biohacking routine, has been dating Tolo for three years. The pair went public with their relationship in December.
“I like that Kate is a science experiment with me,” Johnson wrote on X.
The feeling appears to be mutual.
“Thanks for looking after me bby,” Tolo commented on Johnson’s post.
“I’ve got you,” he replied.
