Short answer
Yes, microplastics have now been found in human testicles and semen, and a few studies link more plastic with poorer sperm measures. But those studies are small, observational and rely on lab methods that are still being refined. Nobody has shown that microplastics cause infertility, or that cutting your exposure improves sperm. Worth taking seriously. Not worth panicking about.
Grim headline to wake up to, we know. So here is what each study actually measured, and what it can and can't tell you.
What are microplastics?
Microplastics are plastic particles between 1 micrometre and 5 millimetres across, either made that small or formed when bigger plastics break down. Nanoplastics are smaller still. They have been detected in testes, semen, follicular fluid and the placenta, but reviewers say their effects on human reproduction remain poorly understood (Hyman et al., 2026).
Are there microplastics in testicles?
Hu et al., 2024: 23 human testes
What the research found: Every one of the 23 human testes tested contained microplastics, as did all 47 dog testes. Human levels averaged around 330 micrograms per gram of tissue, nearly three times the level in dogs, and polyethylene was the most common type (Hu et al., 2024).
What it doesn't prove: Sperm counts were only collected from the dogs, so the study tells us nothing about sperm counts in the men. The method it used, pyrolysis gas chromatography, has since been questioned: a 2025 study in human blood concluded it isn't currently suitable for measuring polyethylene or PVC in biological samples, because other material can create false positives (Rauert et al., 2025).
Do microplastics in semen lower sperm count?
Zhang et al., 2024: 113 men in China
What the research found: Microplastics turned up in the semen and urine of all 113 men, who typically carried three to five types. Each extra type detected was linked with lower total sperm count, concentration and progressive motility. The standout was PTFE, the non-stick coating on pans, which was linked with lower sperm concentration (Zhang et al., 2024).
What it doesn't prove: It's a single snapshot. It shows plastic and poorer sperm measures turning up together, not that one caused the other, and it didn't test clothing or any change in habits.
Other studies don't all line up. In 45 men at a fertility centre, plastic turned up in 34 samples, but there was no significant link with sperm concentration or count (Guo et al., 2025). A study of 115 Malaysian men found microplastics in every sample but didn't look at sperm quality at all (Praveena et al., 2026).
What about IVF and follicular fluid?
Montano et al., 2025: 18 women having IVF
What the research found: Microplastics were present in the follicular fluid, the fluid around a developing egg, of 14 of 18 women having assisted reproduction in Italy. Higher levels tracked with higher FSH (Montano et al., 2025).
What it doesn't prove: There was no link with fertilisation, miscarriage or live birth. Eighteen women is a starting point, not an answer.
In 51 couples having IVF, higher polyethylene and PVC nanoplastics in follicular fluid were linked with lower fertilisation rates, and PVC in seminal plasma with lower motility. Neither partner's levels were linked with implantation or clinical pregnancy (Kong et al., 2025). And at ESHRE's 2025 meeting, a Spanish team reported microplastics in 69% of follicular fluid samples from 29 women and 55% of seminal fluid samples from 22 men. That was a conference abstract, it didn't assess fertility, and the lead researcher said there was "no need for alarm".
Is polyester underwear to blame?
No study has tested underwear. In the Zhang study, the strongest signal came from non-stick PTFE, not polyester. PET, a polyester, was among the plastics found in semen, but these studies can't say where any of it came from. Our guide to polyester underwear and sperm count goes through the fabric question properly.
How can you cut microplastic exposure without losing the plot?
Nobody has shown that reducing exposure changes the plastic in your semen or improves sperm. These are cheap, low-effort swaps based on where particles have been measured coming from, not a fertility plan:
- Stop microwaving food in plastic. Microwaving released the most particles of any use tested, with some containers shedding millions of microplastics per square centimetre in three minutes (Hussain et al., 2023). Glass or ceramic does the job.
- Retire scratched non-stick pans. A scratched PTFE coating may shed thousands to millions of particles in simulated cooking (Luo et al., 2022), and PTFE was the plastic Zhang's team linked with lower sperm concentration.
- Don't assume bottled water is the clean option. One analysis estimated around 240,000 plastic particles per litre of bottled water, about 90% of them nanoplastics (Qian et al., 2024).
- Spend your effort where the evidence is stronger first. Smoking, heavy drinking and regular heat have clearer links with semen quality (NICE, 2026). Our guide to protecting sperm from heat covers the easy wins.
- Trying for a while? A semen analysis through your GP or clinic tells you far more than any plastic headline.
Where does this leave you?
Microplastics are in the male reproductive system. Whether they harm fertility at everyday levels is an open question, and the honest answer right now is "we don't know yet". If you'd like to check the factor with firmer evidence behind it, take our free five-question Heat Check, an educational habits quiz rather than a fertility test. Every source we use sits in our research hub.
Frequently asked questions
Do microplastics cause male infertility?
That hasn't been shown. Human studies find plastic alongside poorer sperm measures in some men, but they can't prove cause, and results are mixed.
Can I get my sperm tested for microplastics?
There's no standard clinical test. Research labs use different methods, and some are still being validated (Rauert et al., 2025). A standard semen analysis is the useful test.
Should I bin my polyester boxers?
No study has linked underwear fabric to plastic in semen. Choose underwear for fit and comfort, and keep heat down.
Do IVF labs expose embryos to plastic?
Labs use a lot of plastic, but direct evidence that standard procedures raise exposure or affect outcomes is scarce, so any impact is speculative for now (Mao et al., 2026).
References
- Hu CJ et al. Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis. Toxicol Sci, 2024. PMID 38745431
- Zhang C et al. Association of mixed exposure to microplastics with sperm dysfunction: a multi-site study in China. eBioMedicine, 2024. PMID 39342804
- Guo Y et al. The presence of microplastics in human semen and their associations with semen quality. Toxics, 2025. PMID 40711011
- Praveena SM et al. Microplastics in human semen among Malaysian men. Environ Res, 2026. PMID 41903729
- Montano L et al. First evidence of microplastics in human ovarian follicular fluid. Ecotoxicol Environ Saf, 2025. PMID 39947063
- Kong F et al. Polyethylene and polyvinyl chloride nanoplastics in human follicular fluid and seminal plasma. ACS Nano, 2025. PMID 40689763
- ESHRE. Microplastics discovered in human reproductive fluids (conference abstract press release), 2025. EurekAlert
- NICE. Fertility problems: assessment and treatment (NG257), 2026. nice.org.uk
- Hyman S et al. Microplastics and reproductive health. Hum Reprod, 2026. PMID 42114971
- Rauert C et al. Assessing the efficacy of pyrolysis-GC-MS for nanoplastic and microplastic analysis in human blood. Environ Sci Technol, 2025. PMID 39851066
- Mao D et al. Reproductive risks of microplastics in assisted reproduction. eBioMedicine, 2026. PMID 42585988
- Hussain KA et al. Assessing the release of microplastics and nanoplastics from plastic containers and reusable food pouches. Environ Sci Technol, 2023. PMID 37343248
- Luo Y et al. Raman imaging for the identification of Teflon microplastics and nanoplastics released from non-stick cookware. Sci Total Environ, 2022. PMID 36030853
- Qian N et al. Rapid single-particle chemical imaging of nanoplastics by SRS microscopy. PNAS, 2024. PMID 38190543
Last reviewed 24 September 2026.
