Glucosamine and other glycosaminoglycans, available over the counter, have been reported in the medical literature as effective treatments for interstitial cystitis, which is sometimes called painful bladder syndrome. There is a nutritional product, CystoProtek, marketed specifically for this condition. A clinical trial supported its effectiveness. So I did a search for other dietary supplements marketed for bladder health. I found Vesteva from Vitamin Research Products, which is formulated to treat urinary incontinence and overactive bladder.
Vitamin Research Products provides an on-line library of articles about its supplements and their ingredients. Each article provides an extensive list of references from the medical literature. I consider most of these articles to be informative and well-documented (I wrote some of them myself). So I checked the VRP library to see the evidence for Vesteva's benefits.
Vesteva contains calcium, phosphorus, magnesium, and a proprietary blend of three-leaf caper (Craveta nurvala) and horsetail (Equisetum arvense). I'm interested in the herbs, since everyone needs mineral for health in general. According to the VRP article, these herbs help to “maintain proper bladder tone.” The references for Craveta and Equisetum include several handbooks of Chinese and Indian herbal medicine, plus a couple of references to medical journals from India and Australia.
I checked the medical literature with the PubMed search engine provided by the National Library of Medicine. As search words, I used “craveta urinary” and “equisetum urinary”. I was surprised to find nothing for craveta, and for equisetum, just 4 articles about the use of this herb as a diuretic. The VRP article also presents data on urinary frequency from clinical trials in Australia, but the reference is “unpublished research”.
Absence of evidence is not evidence of absence, so I don't know whether this dietary supplement does what it's advertised to do. Maybe the handbooks of Asian herbal medicine have important information on bladder health that our medical research community has not yet picked up.