I agree not only does 21 women not make for a very good sample size, but the duration of 5 days is way to short. When hair takes about 6 weeks to grow even when tweezed, a 5 day test is not near long enough. What was the test not carried out longer. I suspect that like fad diets, the body adjusts to changes in food intake and a longer test would have not given them the results that they wanted to publish.
Anyway, it would be good to have a valid long term test conducted.
Martha Montgomery, CCE
Puget Sound Electrology