I had no success with NAC but with MSM (methylsulfonylmethane).

MSM generally supports hair growth so I tested it. But the effect was that the pulling also stopped.

No I am taking it regularly and there is longer a pulling urge.

Dosage: 3 gr. daily together with a lot of Vitamin C in orange juice. I take the powder because that is cheapest.
I take a daily multivitamin also as well as Vitamin D and B.