You may doubt the medication's efficacy when the real issue is inconsistency, not ineffectiveness
A medium dose of molybdenum (25 mg/L) enhanced sperm parameters (epididymal index, sperm motility, sperm number, and morphology), whereas a high dose ( 100 mg/L) had no significant effect on such parameters (137)
Athauda D, Maclagan K, Skene SS, Bajwa-Joseph M, Letchford D, Chowdhury K, Hibbert S, Budnik N, Zampedri L, Dickson J, Li Y, Aviles-Olmos I, Warner TT, Limousin P, Lees AJ, Greig NH, Tebbs S, Foltynie T (2017) Exenatide once weekly versus placebo in Parkinsons disease: a randomised, double-blind, placebo-controlled trial
al, Br J Pharmacol