Forskolin has been used in Ayurveda medicine for many years to treat far more serious conditions and I highly caution against using it for weight loss unless further valid studies are completed. Note that the study below was done in 2005 and no further studies were either attempted and/or deemed suitable for publication thereafter. That is a major red flag.
Obesity Research (2005) 13, 1335–1343; doi: 10.1038/oby.2005.162Body
Composition and Hormonal Adaptations Associated with Forskolin Consumption in Overweight and Obese Men
Addendum: I tried contacting author of study and the email bounced.
Upon furthre research, I found a second study actually disproving the weight loss effects of Forkskolin. See conclusion noted below (from abstract).