How Long Does it Take for CBD to Work? Home › Forums › How Long Does it Take for CBD to Work? This topic has 3 replies, 4 voices, and was last updated 4 years, 7 months ago by dev7. Viewing 1 post (of 1 total) Author Posts March 3, 2019 at 2:08 am #1715 Liz SMember CBD oil, when taken orally, takes from 20 to 40 minutes to be effective. The vape is quicker. Author Posts Viewing 1 post (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In