Can a regular lemon be used if you can't find meyer lemons?

I need to add: Aargersi's method is right on! It is the pith of the lemon that is very bitter. Besides having much sweeter juice, Meyer Lemons have a very thin skin and very little pith.

I think that you can. The original recipe specified lemon and I changed the recipe to specify Meyer lemon because the taste is so different. Meyer lemons are much sweeter and have none of the bitterness of "regular" lemons. I have even made the tart substituting a lime, which also is not as sweet as a Meyer lemon.

Yes I had to do that a couple weeks ago - I cut off the zest and used it, then removed and tossed the white pith, removed the seeds and used the lemon. Also I ended up using 3 - they were small