I asked my new dentist if I could buy bleach while I was there, I've already got the trays from my last one. She said they didn't have it in stock and I should just buy it from the Philips website. I'm wary about buying things like that online so thought I'd be okay with her recommendation but I'm not getting very far because it looks like it's only professionals who can buy it from them, is that right, does anyone know? And if so, where do you buy yours?