I think people go about phenibut the wrong way.
If you want to use high doses for euphoria or for social occasions, I'd take it once, wait at least 3 days before using it again, preferably a week. Taking high doses every day guarantees side effects, withdrawal symptoms, and severe rebound anxiety. Using high doses on consecutive days, then stopping, then starting you're still gonna be dealing with rebound effects with a cycle like that.
I think phenibut is far more beneficial taken in regular, small doses. In Russia, where it's been a pharmaceutical drug for 50 years, doctors prescribe it to be taken 3 times a day, in dosages ranging from 250 to 500 mg. So 500 mg in the morning, 500 mg in the afternoon, 500 at night. In this dosage range you won't get euphoria but it acts as a mild tranquilizer, mood tonic, and nootropic. You'll notice you have an.increase in confidence, mood, and motivation, without sedation or euphoria. Its very functional taken like this, and since you have a steady level in your bloodstream you aren't dealing with constant cycling between feeling great and feeling like shit. You'll find you are more confident, optimistic, and socially adept and many people notice improvements in all areas of their life.
People always assume you'll have got keep taking more and more, but they simply not the case if you aren't chasing a buzz. There's no point getting anywhere above 2 or 3 grams a day, the side effects negate the benefits. For me it's better tham benzos, it doesnt dull your personality or fuck up your cognition, its effects feel completely natural.
That being said, you still have to slowly taper off as any regular use of phenibut will create some degree of dependency. I just cant see how peoppe get up to like 20 grams a day, I'd be s total nutcase at that dose. I guess some people just chase the euphoria they got from the initial dose, but you won't ever get there again with regular dosing, it's a futile pursuit.