How to Punctuate Conjunctive Adverbs (However, Therefore, Moreover)

Grammar rules

Words like "however," "therefore," "moreover," "furthermore," "consequently," and "nevertheless" are conjunctive adverbs — they connect two ideas the way a conjunction does, but they're grammatically adverbs, which means they follow different punctuation rules than "and," "but," or "so." Getting the punctuation wrong is extremely common because these words feel like conjunctions even though they don't behave like one.

At the start of a sentence: comma after

Joining two complete sentences: semicolon before, comma after

This is the one people get wrong most often — using just a comma where a semicolon (or period) is required.

Because "however" isn't a true conjunction like "but," a comma alone can't join two complete sentences around it — you need a semicolon or a period, exactly as if "however" weren't there at all.

Mid-sentence, not joining two clauses: commas on both sides

Here "however" is inserted into a single sentence as a parenthetical aside rather than connecting two independent clauses, so it gets treated like any other interrupting phrase — commas on both sides.

Quick reference

• Starting a sentence: However, [rest of sentence].
• Joining two full sentences: [Sentence one]; however, [sentence two].
• Mid-sentence aside: [Sentence part], however, [sentence continues].

Why this is worth getting right

The semicolon-vs-comma version of this mistake produces a comma splice, which is one of the more noticeable punctuation errors to an attentive reader — it's worth the extra beat of checking, especially in formal or professional writing where "however" and "therefore" show up constantly.

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