Food Supplements in the Treatment of Male Infertility: A Critical Review on Their Formulations and Use

Background: Dietary supplements (DS) represent a possible approach to improve sperm parameters and male fertility. A wide range of DS containing different nutrients is now available. Although many authors demonstrated benefits from some nutrients in male infertility, their real effectiveness is still under debate. The aim of this study was to critically review the composition of DS using the Italian market as sample. Materials & Methods: Active ingredients and their minimal effective daily dose (mFED) were identified through literature search. Thereafter, we created a formula to classify the expected efficacy of each DS. Considering active ingredients, their concentration and the recommended daily dose, DS were scored into three classes of expected efficacy: higher, lower and none. Results: Twenty-one DS were identified. Most of them had a large number of ingredients, frequently at doses below mFED or with unproven efficacy. Zinc was the most common ingredient of DS (70% of products), followed by selenium, arginine, coenzyme Q and folic acid. By applying our scoring system, 9.5% of DS fell in higher class, 71.4% in lower class and 19.1% in the class with no expected efficacy. Conclusions: DS marketed in Italy for male infertility frequently include effective ingredients but also a large number of substances at insufficient dose or with no proven efficacy. Manufacturers and physicians should better consider the scientific evidence on effective ingredients and their doses before formulating and prescribing these products.