"i took this and it&#039;s the best thing i have ever tried. the first couple of days i went by the directions then i doubled the dose. and i lost 20 pounds in 2 weeks.  it did make me feel very jittery and my heart rate was going 90 to nothing but i was determined to lose weight.! and a little information do not i repeat ( do not ) take fastin before you get in a tanning bed. tan first then take it. it made me very very strange in a bad way.  i&#039;m no doctor but when i increased my dose i had the shaking and the increased heart rate. but it never harmed me."