Fast Fact – Caffeine by admin | Jun 27, 2018 | Fact Slides | 0 comments It takes 45 minutes for caffeine to be fully absorbed by the body. Its half-life is 3-4 hours. Submit a Comment Cancel reply Your email address will not be published. Required fields are marked *Comment Name * Email * Website This site uses Akismet to reduce spam. Learn how your comment data is processed.