
Circulate Health, a Seattle health longevity startup, today announced $12 million in seed funding.
The company is partnering with two-dozen clinics in eight states to provide a blood-cleaning service for patients in pursuit of longer, healthier lives. It recently published a study of 42 adults showing potential benefits following repeated treatments.
Circulate is deploying machines that provide therapeutic plasma exchange along with protocols aiming to support longevity and specially trained nurses to operate the devices. The goal is to deliver a circulatory-system tune up that cleans out inflammatory factors and biological compounds associated with aging. The machine removes a patient’s blood, separates out the liquid plasma, and returns clean blood cells with a replacement protein fluid.
“The first step is to get [plasma exchange] out there and really be the first outpatient option for what I consider the coming renaissance of plasma exchange — the idea of targeted blood cleaning,” said Dr. Brad Younggren, Circulate’s co-founder and CEO.
Since May 2024, Circulate has provided more than 1,000 treatments, which run about $8,000-$10,000 for a single session. The procedure is not proven to slow aging or covered by insurance.

Plasma exchange is considered medically effective for conditions including certain cases of multiple sclerosis and leukemia, Guillain Barre syndrome, sickle cell disease, some organ transplant situations, and other specific conditions.
The treatment is more recently being pitched as the next big thing by some promoters of biohacking — a lifestyle that includes using cutting-edge and not necessarily scientifically verified strategies for improving mental performance and longevity.
Circulate operated in stealth mode for a couple of years and officially launched in January 2024 when Younggren came on board. Its co-founder is Dr. Eric Verdin, CEO of the Buck Institute of Research on Aging in Novato California. Verdin’s research is the scientific basis of Circulate’s services.
The company partnered with the Buck Institute to research the impacts of plasma exchange and in May published a study in the journal Aging Cell.
The experiment looked at numerous age-related biomarkers found in cells that can be used to calculate someone’s “biological age.” It compared three groups of participants who were nearly 67 years old on average: one that received a placebo, one that received six plasma exchanges, and one that received six exchanges that included a dose of antibodies. The group receiving exchanges with antibodies fared the best, with a biological age reduction of 2.61 years on average.
“We saw a lot of expected outcomes that would be consistent with cellular rejuvenation,” Younggren said.
Study limitations
But the encouraging results come with significant caveats. Circulate’s study was small and did not look for impacts that extended beyond the three to five months of treatments. The research also didn’t measure changes to how a patient felt or test their cognitive health.
In a May article about the study in the New York Times, multiple medical experts questioned the significance of the findings.
Dr. Jeffrey Winters, chair of transfusion medicine at the Mayo Clinic, said the results don’t indicate the therapy will lead to longer, healthier lives, telling the Times that the proof of longevity benefits “really isn’t there.”
Critics also noted that the last of the three blood samples taken during the study found reduced improvements compared to earlier samples, suggesting the benefits could wane over time. And there are safety concerns around the risk of infections or other complications with the treatment, which takes about two hours.
Most of the startup’s partners are longevity clinics whose services can include: full-body MRIs used to look for early signs of cancer or other issues; genomic sequencing; more detailed blood analysis than is routinely performed by medical providers; and imaging of coronary arteries.
Younggren acknowledged that further research into the impacts of plasma exchange is warranted, and said the company is analyzing data routinely collected at the clinics as another source of insight.
People without thousands of dollars to spend on elective services can sell or donate their plasma for use in lifesaving medical treatments — and gain some of the potential benefits of the commercial treatment.
Younggren highlighted differences with Circulate’s protocol that try to boost the longevity impacts. Circulate removes a larger volume of plasma and replaces it with a protein solution called albumin instead of the saline provided in donations. The startup also gives a dose of an antibody that could aid in “cellular rejuvenation,” he said.
While longevity care in general is expensive, Younggren suggested that the economic — not to mention personal — benefits of preventing costly disease could pencil out at some point.

Longing for longevity
Younggren has worked for decades in medicine, serving as chief medical officer at Seattle telehealth startup 98point6 for seven years. He recruited Robbie Schwietzer, the former chief product officer at 98point6 and past operating partner with Khosla Ventures, to the Circulate team as chief operations officer.
Khosla was the lead investor in the newly announced seed round, which helped pay for the study published in Aging Cell. Seaside Ventures and CSC Ventures also invested.
Circulate’s U.S. competitors include MaxWell Clinic and Next Health, which also provide plasma exchange to promote longer life.
Longevity tech is an evolving sector that attracted $1.8 billion in investments from 2021 through the first quarter of this year, according to PitchBook. While the field’s focus was once on age-related ailments such as cardiovascular and neurological diseases, it’s turning to biological factors associated with aging and extending lifespans, PitchBook noted.
Big names in tech such as Jeff Bezos and OpenAI’s Sam Altman are backing health longevity startups. The Trump administration includes proponents such as Robert F. Kennedy Jr., the Secretary of Health and Human Services, who said he follows an anti-aging protocol and is promoting a “make American healthy again” initiative.
Younggren said the startup could possibly apply for U.S. government funding to support research.
“This notion of making America healthy again,” Younggren said, “fits right in with what we’re trying to do.”
https://ift.tt/zetyO1G July 01, 2025 at 03:00PM GeekWire
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