> What's really cool is that the paper used low-dose capsaicin (just 5 μg/kg injected), and it completely restored hippocampal FOS activity and memory in older mice.

There are countless papers published where simple ingredients produce miracles in mice. Most of them don’t replicate.

If you look up most food ingredients you can find someone, somewhere claiming to have used it to produce amazing outcomes in mice. After you read a lot of those you learn not to take individual papers seriously if the claims seem too good to be true.