That’s a good point. In situations of sun exposure, our rule of thumb is that you want to expose yourself for about half the time it takes for your skin to turn pink. It is hard to apply that to tanning beds as they are designed so you only tan, not burn.
I also understand your feelings towards advocating tanning beds. It is so important to keep in mind that tanning beds should be treated as if you are getting sun exposure. Keeping in mind what Rhennessey said, you may have to be even more aware of your time under tanning bed to be sure you are getting safe, sensible exposure to produce a good amount of vitamin D.
While we would recommend sun exposure and supplementation before tanning beds, they can be a good option for those who have a more difficult time getting outside or don’t wish to use supplements.