“They whisper of science, of secrets untold,
Of blood bought with silver, of youth bought with gold. But under the glamour where dark currents roam. Or is this just good old-fashioned Adrenochrome?” – anonymous
Billionaire tech investor Peter Thiel has never hidden his fascination with life extension and human longevity. Best known as a co-founder of PayPal and an early backer of Facebook, Thiel has also become one of Silicon Valley’s most vocal advocates for radical anti-aging science. His interests have ranged from cryonics—preserving the body after death in hopes of future revival—to more recent fascination with a controversial procedure known as parabiosis, a process that involves injecting the blood of young people into older individuals in an attempt to slow or even reverse aging.
Parabiosis is not a new concept. The idea dates back to 19th-century experiments in which scientists stitched two animals together so they shared a circulatory system. More modern studies, such as those from Stanford and Harvard in the early 2000s, found that older mice exposed to young blood showed signs of tissue regeneration and improved muscle and brain function. These findings sparked excitement in the longevity community — and alarm among ethicists. While early animal research was intriguing, the leap from mice to humans remains scientifically unproven and ethically fraught.
Thiel has reportedly explored funding or investing in companies researching the potential of young blood transfusions. One such company, Ambrosia, briefly made headlines for offering young plasma transfusions to older clients for thousands of dollars per session. However, the U.S. Food and Drug Administration (FDA) issued warnings against the practice in 2019, calling it “unproven and potentially harmful.” There is no credible clinical evidence showing that the infusion of young blood has any anti-aging benefit for humans.
Despite that, the allure of parabiosis persists in the transhumanist corners of Silicon Valley — a culture that views aging as a technical problem to be solved rather than a natural process to be accepted. For Thiel and others in the life-extension movement, the dream is not just to live longer, but to conquer mortality itself. In this worldview, biology is a system that can be hacked, optimized, and upgraded.
Critics, however, see something more troubling: a techno-elite flirting with pseudo-scientific immortality experiments while ignoring profound ethical questions. The very notion of using young people’s blood to extend the lives of the wealthy evokes dystopian imagery — a modern echo of vampiric folklore, where vitality is literally extracted from the young to sustain the old. Ethicists have warned that such practices could create a black market for “youth plasma” and deepen social inequality in the pursuit of eternal youth.
Scientists caution that there’s still far too little evidence to justify such experimentation. While young plasma transfusions may have some theoretical benefits — such as replenishing certain proteins or reducing inflammation — the human body’s aging process is vastly more complex. Aging is influenced by genetics, lifestyle, environmental toxins, and cellular damage accumulated over decades. No single “youth elixir,” especially one based on another person’s blood, is likely to reverse all of that.
In the end, Peter Thiel’s interest in parabiosis says as much about the mindset of Silicon Valley as it does about science. It reflects a belief that wealth and innovation can overcome nature’s limits — that death itself is just another engineering challenge waiting to be solved. Whether this vision proves to be scientific progress or hubristic folly remains to be seen. For now, parabiosis stands as a striking symbol of humanity’s oldest dream and newest obsession: the quest to live forever.