Do over the counter fat burners work?

Short Answer

No. Well, at least not very well.

Long Answer

First things first, if you’re not already lean, there is no point to even consider an over the counter fat burner. Once you’re at a low body fat percentage, then consider if a fat burner is right for you.

Over the counter fat burners are almost always simply stimulants, meaning they just increase energy expenditure. The most common fat burners are caffeine and ephedrine. Ephedrine is banned in the US & Canada. However, ephedrine has been shown in many studies to cause weight loss, with an average of 1kg/month.[1] More information on a common ephedrine and caffeine stack can be found on Lyle McDonald’s site

While caffeine is a thermogenic and will increase energy expenditure, increase strength, decrease appetite, & actually increases mental stimulation, it isn’t a wonder drug when taken for fat loss. Regular use of caffeine will lead to a tolerance. Three separate studies showed a small increase in fat burning with caffinene supplementation, although this may just be due to the increase in activity due to the stimulatory affect of caffeine.[2]

Further Reading
  1. Paul G. Shekelle, MD, PhD; Mary L. Hardy, MD; Sally C. Morton, PhD; Margaret Maglione, MPP; Walter A. Mojica, MD, MPH; Marika J. Suttorp, MS; Shannon Lt “prescription of an ephedrine/caffeine product was not associated with adverse cardiovascular outcomes. This was found across a wide range of patient subgroups, different cardiovascular outcomes, different assumptions about exposure, and different utilization pattern. Rhodes, MFA; Lara Jungvig, BA; James Gagné, MD “Efficacy and Safety of Ephedra and Ephedrine for Weight Loss and Athletic Performance: A Meta-analysis” JAMA. 2003;289:1537-1545