Fastin is a form of the popular prescription ingredient Phentermine. They use a Phentermine hydrochloride capsule with 30mg, but equivalent to 24mg Phentermine. It is a white crystalline powder soluble in water and alcohol. Inactive ingredients are also included, and it does have food grade shellfish incase you are allergic to that type of ingredient. It is for the short term use in the management of exogenous obesity, and by short term they do mean a few weeks in combination with a strict weight loss regimen. You should take one capsule 2 hours after breakfast, however it is not to be used within a few hours of bedtime as it may cause insomnia. 30mg daily has been shown to be adequate for most in suppressing appetite for 12-14 hours. However, with that dose, side effects commonly associated with Phentermine are likely. This particular form was manufactured by King Pharmaceuticals for SmithKline Beecham. But in 1998, it was removed from the market.