It is often prescribed for individuals with pernicious anemia or other conditions that impair B absorption (for example, after gastric surgery or in certain digestive disorders)
(Reference Shimizu, Hara and Hira21,Reference Radic, Mijovic and Tatalovic22)
It is something more uncomfortable: what happens when genuinely promising science encounters a culture optimized for hype, when regulatory frameworks built for pharmaceutical companies fail to anticipate decentralized self-experimentation, and when the financial interests of a grey market align perfectly with the psychological vulnerabilities of people who want to be stronger, younger, leaner, and sharper than they currently are
Clinical insight: The difference in mechanism is clinically significant
Impaired synaptic plasticity and decreased excitability of hippocampal glutamatergic neurons mediated by BDNF downregulation contribute to cognitive dysfunction in mice induced by repeated neonatal exposure to ketamine
The most common reason is pulling the pen away too quickly
