Comma (or No Comma) After Conjunctive Adverbs Based on Syllable Count and Context

After a conjunctive adverb with two or more syllables (however, therefore, consequently), use a comma. After a conjunctive adverb with only one syllable (yet, still, thus, so, then), use no punctuation.

When a coordinate conjunction (and, but, or, nor) precedes a word that could be a conjunctive adverb, use the punctuation appropriate for the coordinate conjunction, not the conjunctive adverb punctuation.

If a word that can be a conjunctive adverb is in position at the front but does not have an independent subject and verb after it, use a comma in front of it — not a period or semicolon — because it is functioning as an adverb, not a conjunction. When there is a coordinate conjunction followed by a conjunctive adverb-type word and there is NOT an independent subject and verb after it, do not use a comma before the coordinate conjunction. When there is no coordinate conjunction but there is a conjunctive adverb-type word and there is NOT an independent subject and verb after it, use a comma to replace the missing conjunction.