If Vilitra 40 mg contains vardenafil, it is not known to lower testosterone. Clinical studies of vardenafil have generally found no detrimental effect on testosterone or other reproductive hormones. One randomized study found no significant changes in testosterone, LH, FSH, or prolactin after 6 months of vardenafil use. S ScienceDirect +1 Interestingly, one small study in men with type 2 diabetes and low testosterone found testosterone increased during long-term vardenafil treatment, but this is not enough evidence to use vardenafil as a testosterone treatment. P PubMed One important issue: 40 mg is higher than the usual recommended vardenafil dose (maximum 20 mg) for ED. Higher doses can increase adverse effects without necessarily improving erections. If you're concerned because you've noticed low libido, fatigue, or reduced erections while taking Vilitra, a morning testosterone blood test (often repeated if low) can help determine whether testosterone is actually reduced.