shelf life vs time period

shelf life and time period both are nouns.

Word	Noun	Adjective	Verb	Adverb
shelf life	Yes	No	No	No
time period	Yes	No	No	No

As nouns, time period is a hypernym of shelf life; that is, time period is a word with a broader meaning than shelf life:

shelf life: the length of time a packaged food or drug will last without deteriorating
time period: an amount of time

Other hypernyms of shelf life include period, period of time.

shelf life (noun)	time period (noun)
the length of time a packaged food or drug will last without deteriorating	an amount of time