A key barrier to the consistent use of condoms is their negative effect on sexual pleasure. Although sexual pleasure is a primary motivation for engaging in sex and is an integral part of overall sexual health, most programs to improve sexual health operate within a pregnancy and disease-prevention paradigm. A new condom, CSD500 (Futura Medical Developments; Surrey, UK), containing an erectogenic drug was developed for use among healthy couples to improve sexual pleasure by increasing penile firmness, size and erection duration. We conducted a randomized controlled trial to test whether promoting the novel condom CSD500 for improved sexual pleasure is effective in reducing condomless sex compared to the provision of standard condoms with counseling for pregnancy and disease prevention. We randomized 500 adult, heterosexual, monogamous couples in Thanh Hoa province, Vietnam to receive either CSD500 (n = 248) or standard condoms (n = 252). At enrollment and after 2, 4, and 6 months, we interviewed women and sampled vaginal fluid to test for the presence of prostate-specific antigen (PSA), an objective, biological marker of recent semen exposure. We registered the protocol before trial initiation at ClinicalTrials.gov (identifier: NCT02934620). Overall, 11.0% of women were PSA positive at enrollment. The proportion of follow-up visits with PSA-positivity did not differ between the intervention (6.8%) and control arms (6.7%; relative risk, 1.01; 95% confidence interval, 0.66-1.54). Thus, we found no evidence that promoting an erectogenic condom to women in a monogamous, heterosexual relationship in Vietnam reduced their exposure to their partner's semen. These findings might not hold for other populations, especially those with a higher frequency of condomless sex.