My gym mate took NAC once and says the mental noise just disappeared

My gym mate tried NAC for the first time recently after reading people talk about it for anxiety and obsessive thinking. He had also been feeling off from some rebounds after using phenibut, so he figured he’d experiment with it without expecting much.

What surprised him is how quickly he felt different. He said the anxiety faded fast, but more than that, he suddenly felt calm, present, and strangely motivated to tackle work he’d been avoiding for ages. The constant rumination in his head seemed to quiet down almost immediately.

He kept asking whether placebo can really hit that hard because the shift felt unusually noticeable for something that gets described as a basic supplement. From the outside, it looked less like stimulation and more like some layer of internal friction disappeared for a while.

What stood out most is that he wasn’t chasing euphoria or trying to get high. He just seemed relieved to have a break from the constant mental looping and tension that had been building up recently.

Has anyone else known someone who reacted that strongly to NAC right away? Did the calmer mood and clearer head stick around over time, or did it level out once the novelty wore off?