How to use niz

[Highlander]

If you have the highest strength one, is it once a week or twice a week?

[25 going on 65]

I tried twice every week and that seems too often. I would go no more than once a week unless the prescribing doc says otherwise.
Massage it thoroughly into your scalp in the shower, wait five minutes before rinsing it out. It definitely has a drying effect so you might want to follow up with conditioner (preferably with no SLS or ALS to minimize the chances of irritation/unnecessary shedding)