I know Phenibut can cause withdrawal after 3+ day's of use, what I was wondering is if I used Xanax for 2 day's then went into Phenibut for 2 day's would I expirence withdrawal since they are both gabaergics? Or does it not matter because they are different substances? I have used some L-Theanine also. I just got clean from H using Kratom which was the miracle that saved me, and I do NOT want to suffer any more withdrawals. It took me a month+ of trying everything to get clean and Kratom was the only thing that worked.