According to Amazon, the best brand of 5 HTP is Dr. Emil Nutrition as it's a bestseller and top-rated product. But It's formulated with serotonin synthesizers so if you're looking for a supplement that contains a natural source of 5-HTP, you can go for Nature's Way 5-HTP Supplement, NOW Supplements 5-HTP, Solgar 5-HTP, or Nature's Nutrition 5-HTP Capsules.