The criticisms of Costello and Betz are not specific to our study but rather broadly apply to essentially all existing research on so-called dietary supplements derived from botanical sources. We agree that such research can be confounded by the inconsistent potency of these nonregulated preparations.1
In our article we clearly detail the brand name, manufacturer, and labeled contents of our Ginkgo biloba preparation in general accordance with the various guidelines referenced by Betz and Costello. We do not understand their criticism that we used “only 120 mg” twice daily of Ginkgo biloba because this is generally considered a “high dosage”2 and was chosen to correspond to prior similar research. Neither of the 2 other minor herbal preparations in our Ginkgo biloba product has any theoretical or experiential basis for impacting altitude-related illness. We disagree with the suggestion that our trial cannot address the study question because we selected a common brand obtained from a large chain dietary supplement store. Thus, our study readily addresses the “real-world” practicality of what a typical person can expect should they purchase over-the-counter Ginkgo biloba in hope of mitigating acute mountain sickness.
Chow T, Green SM. Studies on Natural Products—Reply. Arch Intern Med. 2006;166(3):370-371. doi:10.1001/archinte.166.3.371