Tomatoes and Sperm: Investigating the Role of Lycopene in Semen Quality

Background

Poor semen quality is a major contributor to infertility worldwide, with treatment options largely limited to assisted reproductive technologies. Dietary antioxidants, such as lycopene from cooked tomatoes, have been proposed as empirical therapies to improve semen quality.

Objectives

To investigate the effect of lycopene on semen quality using both a systematic review and a double-blind clinical trial.

Methods

A systematic review was conducted to evaluate existing evidence on lycopene and sperm health. In parallel, food frequency questionnaires and semen analyses from 94 men were examined for associations with dietary lycopene intake. A double-blind RCT (TOMS2) recruited men with low total motile sperm count (<20 million; n=34), randomising them to lycopene supplementation or placebo for 12 weeks. Outcomes included semen volume, concentration, motility, morphology, oxidative stress, and DNA fragmentation.

Results

The systematic review suggested lycopene may improve semen parameters, though effects varied across studies. In the observational cohort, no associations were found between dietary lycopene and semen quality, while higher BMI correlated negatively with semen volume (rs = –0.29, p=0.03) and morphology (rs = –0.37, p=0.04). In the RCT, lycopene supplementation did not significantly improve semen parameters compared with placebo. However, analysis of all participants combined showed improvements in sperm concentration (5.4 → 8.9 ×106/ml, p=0.01) and total motile sperm count (7.5 → 12.6 ×106, p=0.02).

Conclusions

This study found no evidence that dietary lycopene intake or supplementation improves semen quality, although overall improvements in sperm parameters were observed across participants. The work highlights both the challenges of conducting antioxidant RCTs in male infertility and the need for larger, adequately powered trials. A key limitation was the small sample size.