Researchers studied how triclosan, a chemical found in many antibacterial soaps and products, affects the ovaries and fertility in mice. Female mice exposed to triclosan for up to a year showed signs of losing their eggs faster than normal as they aged, and had longer gaps between pregnancies during their reproductive years. While the number of babies born was similar between exposed and unexposed mice, the findings suggest triclosan might affect how quickly women’s egg supplies decline and their reproductive cycles. This research raises questions about whether this common chemical could impact human fertility.

The Quick Take

  • What they studied: Whether triclosan, a chemical used in antibacterial products, damages the ovaries and affects the ability to have babies
  • Who participated: Female laboratory mice that were fed triclosan in their diet starting at young adulthood and followed for up to one year, compared to mice eating normal food
  • Key finding: Mice exposed to triclosan showed faster loss of their eggs as they aged, especially after 6-12 months of exposure. They also had longer wait times between pregnancies, suggesting their reproductive cycles may have slowed down.
  • What it means for you: This mouse study suggests triclosan might affect human fertility and egg health, but we need human studies to know for sure. If you’re concerned about fertility, reducing exposure to triclosan-containing products may be worth considering, though this is not yet proven in people.

The Research Details

Scientists gave female mice a diet containing triclosan (a common antibacterial chemical) starting when they were young adults. They checked the mice’s ovaries at six different time points over one year to see how the eggs were developing. They also bred the mice and tracked how many babies were born, how long pregnancies took, and other fertility measures.

This is called a longitudinal study because the same mice were followed over a long period of time. The researchers compared mice eating triclosan to mice eating normal food to see what differences the chemical caused. By checking the ovaries at multiple time points, they could see both short-term and long-term effects of the chemical exposure.

This research design is important because it shows how a chemical affects the ovaries over time, not just at one moment. Since mice have similar reproductive systems to humans, findings in mice can help scientists understand what might happen in people. Testing in animals first is necessary before studying effects in humans.

This is a controlled laboratory study, which is good for understanding cause-and-effect. The researchers used a standard mouse breed and measured specific parts of the ovaries under a microscope. However, the study doesn’t specify exactly how many mice were used, which would help readers understand how reliable the results are. Mouse studies are useful but don’t always translate exactly to humans, so human research would be needed to confirm these findings.

What the Results Show

The main finding was that triclosan-exposed mice lost their eggs faster than normal mice as they aged. This was especially noticeable after 6-12 months of exposure. The most mature eggs (called antral follicles) were significantly fewer in triclosan-exposed mice compared to controls at the 9 and 12-month marks.

Second, mice exposed to triclosan had longer gaps between pregnancies, particularly early in their reproductive years. For example, the time between their first and fifth pregnancies was about 19 days longer in exposed mice (135 days versus 116 days). This suggests the chemical may have slowed down their reproductive cycles.

Interestingly, the number of babies born in each litter was similar between exposed and unexposed mice, and there was no increase in stillbirths. This means triclosan didn’t seem to affect pregnancy success once it happened, but rather the timing and frequency of pregnancies.

Early in exposure (at 1-2 months), triclosan-exposed mice showed a trend toward having fewer growing eggs, though this wasn’t as dramatic as the later effects. The pattern of egg loss in triclosan-exposed mice followed a similar aging pattern as control mice, but appeared to happen faster—suggesting the chemical may accelerate normal aging of the ovaries rather than causing a completely different type of damage.

Previous research has suggested that triclosan and similar chemicals can interfere with hormones that control reproduction. This study adds to that evidence by showing specific changes in egg development and reproductive timing. The findings align with concerns that endocrine-disrupting chemicals (substances that interfere with hormone systems) may affect fertility, though more research is needed to understand the exact mechanisms.

The study was conducted only in mice, so we cannot be certain the same effects would occur in humans. The exact number of mice studied was not reported, making it harder to assess how reliable the findings are. The dose of triclosan used (10mg/kg per day) may not directly match typical human exposure levels. Additionally, the study looked at one specific strain of laboratory mice, so results might differ in other mouse populations or species. Finally, the researchers didn’t measure hormone levels, which could help explain why the reproductive cycles were affected.

The Bottom Line

Based on this animal research, there is suggestive but not definitive evidence that triclosan exposure may affect egg health and reproductive timing. If you are concerned about fertility or planning pregnancy, consider reducing exposure to triclosan-containing products (such as some antibacterial soaps and toothpastes) as a precautionary measure. However, this recommendation is based on animal studies and should not replace medical advice from your doctor. More human research is needed before making strong claims about triclosan and human fertility.

Women of reproductive age who are concerned about fertility or planning to become pregnant should be aware of this research. People who use many triclosan-containing products daily may want to consider alternatives. This is less immediately relevant to men, post-menopausal women, or those not concerned with fertility. Anyone with specific fertility concerns should discuss this with their healthcare provider.

In mice, effects on egg loss became noticeable after 2-3 months of exposure and were most pronounced after 6-12 months. If similar effects occur in humans, changes might take months to years to develop. However, we don’t know if or how quickly effects would appear in people, so this timeline should not be assumed to apply to humans.

Want to Apply This Research?

  • Track daily exposure to triclosan-containing products by logging which antibacterial soaps, toothpastes, and personal care items you use. Note the frequency of use and gradually switch to triclosan-free alternatives, tracking the date of each product change.
  • Replace triclosan-containing antibacterial soaps with regular soap and water or triclosan-free hand sanitizers. Check product labels for triclosan in toothpaste, deodorants, and other personal care items, and switch to alternatives. Document which products you’ve replaced and when.
  • If tracking fertility-related metrics, monitor menstrual cycle length and regularity over several months before and after reducing triclosan exposure. Note any changes in cycle consistency. For those trying to conceive, track ovulation patterns and time to pregnancy. Share this data with your healthcare provider to identify any meaningful changes.

This research is based on a mouse study and has not been proven in humans. Triclosan’s effects on human fertility are not yet established. This information should not replace medical advice from your doctor or fertility specialist. If you have concerns about fertility or are planning pregnancy, consult with a healthcare provider. Do not make significant changes to your health routine based solely on this animal research without discussing it with your medical team first.