Protandim states that it boosts the body's antioxidant defense system, but clinical trials evaluating the effectiveness of Protandim as an antioxidant show mixed results, according to Dr. Aaron Emmel, who reviews Protandim's health claims in his blog The Medicine Guy. There is no direct evidence in humans that Protandim combats aging, promotes survival or offers any other health benefit.
However, Protandim users uniformly offer positive reviews on online forums. For example, on Amazon.com, the product received 5/5 stars from all users except those complaining about Amazon.com's prices or shipping procedures. Commentators on The Medicine Guy blog note improvements in muscular dystrophy symptoms, and one reviewer states that she has thicker hair, stronger nails, better skin, and improved triglyceride and bad cholesterol levels after taking Protandim for two months. A reviewer on Supplement Geek also applauds Protandim for improving her chronic Lyme disease symptoms.
Nevertheless, readers should interpret these reviews with caution. As of December 2015, there were only five reviews for Protandim on Amazon.com. The Medicine Guy and Supplement Geek blogs together contained an additional five comments from users. Moreover, in general user testimonials often fail to prove a cause and effect relationship between the supplement and the reported health benefit and thus do not provide strong evidence of a product's effectiveness, according to The Medicine Guy.