“How long is memory loss after general anesthesia?”

I have not encountered any

Good question! It depends on the amount of medication you've been given but you will likely remember everything until the point that you start to receive the anesthesia. And then you won't likely remember anything until after you wake up usually in the recovery room.

This is a poorly understood phenomenon so it’s hard to give you a definite answer. At your age assuming you have no memory deficits at baseline you really shouldn’t have much memory loss. For older people, over 70, they will experience more memory loss with general anesthesia.

During general anesthesia, patients receive multiple agents that render amnesia and unconsciousness. Patients are unconscious during the entire surgery, so there are no memories stored from surgery. Often, a benzodiazepine is administered preoperatively to allay anxiety and these drugs also cause anterograde and mild retrograde amnesia for the preoperative events. The memories of preoperative events may or may not ever be recalled with clarity, and the benzodiazepines have been shown to cloud higher cognitive levels of reasoning and computational ability for as long as a week after surgery.

There shouldn't be any memory loss when you are awake from general anesthesia.