Experts and BHG readers answer.
protect wooden vanity
A good question. If you want to keep the natural or stained appearance of a wooden finish I have had the best luck with a finish designed for the outdoors. I have used a Marine varnish successfully in the past but there might be some more modern finishes that work as well. Ask at your local paint shop what they would recommend to re-finish a wooden front door since the humidity in a bathroom is not that different.