vitamin B6 vs vitamin B complex

vitamin B6 and vitamin B complex both are nouns.

Word	Noun	Adjective	Verb	Adverb
vitamin B6	Yes	No	No	No
vitamin B complex	Yes	No	No	No

As nouns, vitamin B complex is a hypernym of vitamin B6; that is, vitamin B complex is a word with a broader meaning than vitamin B6:

vitamin B6: a B vitamin that is essential for metabolism of amino acids and starch
vitamin B complex: originally thought to be a single vitamin but now separated into several B vitamins

Other hypernyms of vitamin B6 include B-complex vitamin, B, B complex, B vitamin, vitamin B.

vitamin B6 (noun)	vitamin B complex (noun)
a B vitamin that is essential for metabolism of amino acids and starch	originally thought to be a single vitamin but now separated into several B vitamins