A Systematic Review and Evidence-based Analysis of Ingredients in Popular Male Fertility Supplements

OBJECTIVE To study the level of evidence available for ingredients of popular over-the-counter male fertility supplements. METHODS The top 17 male fertility supplements in the United States were identified from the most popular online retailers: A1 Supplements, Amazon, Vitamin Shoppe, and Walmart. Individual ingredients were identified for each supplement. The PUBMED and Cochrane online databases were reviewed for randomized controlled trials studying the efficacy of each ingredient. Each ingredient was categorized based on availability of evidence using an adapted version of the scoring system by the American Heart Association. Scores were assigned to each categorical level of evidence for each ingredient and a composite score for each supplement was calculated. RESULTS Ninety unique ingredients were identified. The 5 most commonly used ingredients were vitamin E, folic acid, zinc, vitamin C, and selenium whereas the 5 ingredients with most evidence were L-carnitine, Vitamin E, Vitamin C, CoQ10, and Zinc. In all, only 22% of ingredients used were found to have published evidence for improvement in semen parameters and only 17% of ingredients had data published showing a positive effect. Our evidence-based analysis demonstrated an average composite rating of 1.66 (on a scale to 5). Evolution 60 and Conception XR had the highest composite scores with 3.6 and 3.5, respectively. CONCLUSION Many male fertility supplements claim to improve fertility; however, their products are rarely backed by evidence and their efficacy remains unproven. Few ingredients used in popular fertility supplements have positive evidence in randomized clinical trials and should therefore be used cautiously. (C) 2019 Elsevier Inc.