Best melatonin brand

My psychiatrist suggested that I take 3mg melatonin to help with the seasonal component of my depression.  I am trying to find a brand that makes pure, synthetic melatonin without any additives.  What brand/s would you suggest? or Where can I find out which brands are the best?

[Alison L, RPh]

Over the counter supplements such as melatonin are regulated as nutraceuticals, not drugs. Scientific data supporting the claimed benefits of neutraceuticals are not always available as they are for traditional pharmaceuticals since nutraceuticals are not regulated as drugs. It should also be noted that Rrgid quality control standards are not required for nutraceuticals and substantial variability can occur in both the potency and the purity of these products. That being said, some reputable companies that manufacture supplements are GNC, Natrol, Natures Bounty, along with many others. Perhaps your psychiatrist prefers his or her patients use a specific brand.