You start getting incoherent after heavy use, even when not currently using. People who know you notice. Jewel said she left an event early because she was upset to see Tony was acting that way. It takes 4-6 days to recover from a heavy run, including getting feeling back in your nerve endings. Taking B vitamins help.

I’d go further and say everyone taking nitrous oxide should be taking b12 supplements.

Absolutely. I have pernicious anemia now (need B12 shots) that I didn't have before, at least not diagnosed when younger.

How much is a "heavy run"? Another commenter mentioned buying many cases.

Some rather serious side effects have been described in a vegetarian (probably already b12 deficient) after just an hour of continuous exposure.

While that was in a clinical setting, it can be quick if you’re already at risk.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

I'd need 4 to 6 days to recover after doing 2 cases or 1200 whippets. I'd be extremely sick for the first 2 or 3 days.