look into vs check up on

look into and check up on both are verbs.

Word	Noun	Adjective	Verb	Adverb
look into	No	No	Yes	No
check up on	No	No	Yes	No

As verbs, look into and check up on are synonyms defined as:

look into and check up on: examine so as to determine accuracy, quality, or condition

Other synonyms of look into include check, check into, check out, check over, go over, suss out.

look into (verb)	check up on (verb)
examine so as to determine accuracy, quality, or condition	examine so as to determine accuracy, quality, or condition
investigate scientifically