The age gate is the notice that opens this site and the line behind it: every client and every therapist is twenty-one or older, whatever the occasion.
The first thing this site shows is a question about age, laid over a darkened page. Answer it and the site opens. That screen is the age gate, and it states a line the house holds everywhere else as well: twenty-one and over, for anyone who books and for anyone who is sent.
The house set its line above adulthood on paper, and it did so on purpose. Amsterdam draws a young crowd at weekends, and many of those visitors arrive in groups with a plan hatched somewhere over the North Sea. A threshold at twenty-one keeps the clientele to people with a few more years of knowing their own minds, and it keeps the roster to the same standard.
A birthday on the day. A stag weekend where the groom is twenty-one but one of his friends is not. A booking placed by an older friend on behalf of a younger one. An offer to pay more. None of these changes the answer, and the office does not treat the question as open. A booking made for somebody else is judged by the age of whoever will be opening the door.
The therapists on the roster are all twenty-one or older as well. The rule is not only about who may book; it describes the whole house.
The notice is not decoration. It tells a visitor, before any page loads, what kind of site this is and whom it is written for, so nobody wanders in at one in the morning without knowing. If you are under twenty-one, close the tab. If you are over it, the first-timers' guide is a calm place to begin, and the WhatsApp booking entry explains how a first message works.