I have company for weekend bathroom sink running very slow. Quick fix

Mine does the same thing. I even used Drano and/or Liquid Plumber. Still doesn't work for long. My next step is to check the trap and see if something is stuck. Hope this helps.

Sounds like you have blockage lower in the drain pipe and need to snake it out. I had the same problem with my kitchen sink and it was a pipe almost all the way out of the house. If you have a snake, use it. Did you take the hair out before you ran the baking soda and vinegar down it? If not get one of those plastic sticks with the barbs on it and pull the hair out as much as possible, then run the baking soda and vinegar to get the gunk out. The hair will make it run real slow.

Here is an article that might be helpful - https://www.familyhandyman.com/plumbing/drain-repair/unclog-a-bathroom-sink-without-chemicals/view-all/

I would open up the drain under the sink to make sure there's no blockage. Make sure to have a bucket and towel set up before you open it.

I did try the vinegar and baking soda - it worked well. Really well. All clear for a great holiday. Merry Christmas and Happy New Year and many thanks! I think the boiling water was the best touch. I have used the other but the boiling water seemed to push the treatment further down the drain. LOL