Swallowed marijuana products are the least predictable and the most difficult to dose. Because the edible must be digested before the THC is absorbed into the bloodstream, it can be from 30 to 90 minutes before you feel anything. During digestion, the delta-9 THC in edible is metabolized by the liver into 11-hydroxy THC -- a more psychoactive form. Some people convert more, others convert less. Fully 1 in 5 people have little to no response to edibles at all! Others have an extreme, uncomfortable way-too-high type feeling.
Be careful with edibles. Start low, go slow. A starting dose of 2.5-5mg for women and 5-10mg for men is recommended, and wait a FULL HOUR before taking another dose, if no effects are felt right away. Once you find your personal best dose, edibles can be a good way to get long-lasting effects, without having to carry around smelly paraphernalia.