[15] He taught and ran the Internet and web engineering program at the UCSC Silicon Valley Extension, in which Asprey created one of the first working instances of cloud computing.

Eventually, the company delivered products to customers in ten countries, including Australia, the United Kingdom, South Africa, and several parts of Asia, making it one of the first worldwide e-commerce businesses.

[28] In July 2018, Bulletproof 360, Inc. reported raising more than $40 million in equity and debt financing, led by the food and beverage investment firm CAVU Venture Partners.

[35][36] The Bulletproof diet promotes the consumption of grass-fed beef and butter and considers soy, wheat, canned vegetables and microwaved foods to be toxic, but fails to provide any evidence to support these claims.

[37] Asprey asserts that mycotoxins are harmful substances produced by coffee-bean-growing molds (among other things) and they are responsible for a wide range of health issues, including inflammation.

[3] Dietitian Lynn Weaver criticized the diet as being hard to follow and supported by only small studies that are "not generally part of the scientific literature used by medical and nutritional professionals".

[33] Dietitians also point out there is no scientific basis for claims of an IQ boost, and that any sense of alertness from Bulletproof Coffee is "just a caffeine buzz".

[40] An article by Scott Gavura commented that "Asprey’s output combines cherry-picked science with pseudoscience, wrapped up in a self-experimentation ethos that superficially sounds compelling but falls short in actual evidence".

[41] In 2020, the Federal Trade Commission sent Asprey a warning letter telling him any "coronavirus-related prevention claims regarding such products are not supported by competent and reliable scientific evidence.

[40] In 2021, the Food and Drug Administration (FDA) sent a warning letter to Asprey's company, Bulletproof 360, stating that the its products were not “generally recognized as safe and effective” for the uses advertised.

[8] As of 2021, he claims to have spent at least two million dollars on "hacking his own biology", including having his own stem cells injected into himself, taking one hundred daily supplements, following a strict diet, bathing in infrared light, using a hyperbaric oxygen chamber, and wearing special lenses when flying or using a computer.

[48] Asprey supported President Donald Trump's nomination of Robert F. Kennedy Jr. to United States secretary of health and human services (HHS).