Walt Disney is not frozen under a theme park; early cryonics figure Robert Nelson said he saw Disney’s ashes. But as of 2024 roughly 600 people are suspended in liquid nitrogen, and the first, psychology professor James Bedford, frozen in 1967, is the only early patient still preserved. Preservation can start only after legal death, and most jurisdictions treat cryonics as a form of disposing of human remains, not medicine; France does not recognize it at all. Teams replace the body’s water with cryoprotectants to vitrify tissue at minus 196 degrees Celsius instead of forming ice.

Critics in the scientific community call the practice pseudoscience. The chemicals are toxic and cause osmotic shock, large organs crack under thermal stress, and biochemist Ken Storey notes the brain’s many regions would each need their own protocol. Then there is money: US fees run from $28,000 to $200,000, often paid by life insurance, and funds must last centuries. Nelson, a former TV repairman who ran the Cryonics Society of California, was sued in 1981 after nine bodies in his care thawed, and nearly all bodies frozen before 1973 were lost to bankruptcies.

• Neuropreservation and KrioRus storing bodies together in Dewar flasks
• The 2018 startup Nectome’s fatal chemical brain preservation aimed at mind uploading
• Why the movement draws technologists such as Peter Thiel and Hal Finney, and spouses’ hostility
• The 2016 UK High Court case of a terminally ill 14 year old who won the right to be preserved
• David Shaw’s cryonics version of Pascal’s wager and Sean Pattinson’s evil reviver objection