[tomlue]

This comment may unnecessarily discourage people from using metformin.

- There is no evidence linking metformin to PSP, let alone a causal relationship. - PSP is also very rare, prevalence ~ 7 per 100,000 [1]. - Metformin is used by 100+ million people [2]. - It has been safely prescribed for type 2 diabetes since the late 1950s [2].

Metformin is a highly effective and widely used medication. It would be unfortunate for people to avoid it based on speculative claims. If there’s specific evidence suggesting metformin as a risk factor for PSP, I’d be interested, but the leap from "mitochondrial complex I inhibition is associated with PSP" to "metformin causes PSP" is unwarranted.

As for the prophylactic use comment: we are all going to decay and die, trying to mitigate those risks with metformin is not unreasonable. There is evidence supporting its potential benefits, though some of these may reflect its established role in managing diabetes. (talk to your doctor, etc.)

[1] https://link.springer.com/article/10.1007/s00415-023-11791-2 [2] https://www.metabolismjournal.com/article/S0026-0495%2822%29...

[Alex3917]

> the leap from "mitochondrial complex I inhibition is associated with PSP" to "metformin causes PSP" is unwarranted

The mechanism of action is relatively straightforward: the inhibition is caused by a building up oxides within the mitochondria, which makes them less efficient at producing energy. And if the mitochondria go long enough without a mitochondrial antioxidant clearing out the oxides, they eventually die. And if enough of the mitochondria within your brain die, you get PSP.

My best guess as to the reason we haven't seen an association between PSP and metformin is that metformin is actually a mitochondrial type I adaptogen rather than a mitochondrial type I inhibitor. I'm definitely not telling people not to take it, but if you are then I think setting a couple Google scholar alerts would be prudent.