Fish Oil and Fertility
Diets rich in healthy fish, such as the Mediterranean diet, have long been known to have a wide range of health benefits. Now these polyunsaturated omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in fish oil and krill oil, are also being studied for their effects on human fertility.
Endometriosis
The omega-3 fatty acids in fish oil were subject to a comprehensive 2025 review study taking a critical look at how omega-3 fatty acids affected over 400 women with endometriosis. The studies showed promising results, but the full effect was masked by some test design problems. For example, one study used olive oil as a placebo against fish oil. Olive oil is itself highly anti-inflammatory, so the study showed less overall difference between the two groups—a score for olive oil! However, even with caveats for the study designs, the authors conclude that omega-3 is responsible for reducing the body’s production of inflammatory cytokines in women with endometriosis and suggest that other beneficial results could be confirmed by future studies (Liu et al., 2025).
In early 2026 a better controlled study was published, with results from a cohort of 289 women with endometriosis. They were given 900 mg per day of EPA and DHA for 12 weeks. The results were quite striking. In addition to the reduced inflammatory biomarkers already indicated in the 2025 review, this study also found a corresponding reduction in pain symptoms, and better overall quality of life rating from the affected women, confirming a beneficial effect which had been missing from the previous research (Huang et al., 2026).
PCOS
Omega-3 fatty acids also are under review for treating polycystic ovary syndrome (PCOS). Omega-3 supplements in the amount of 1800 mg per day, divided into three doses, were used in a double-blind study observing the effects on women with PCOS who were undergoing standard ovulation induction treatment. Achieving pregnancy within two years was the measurable result. The results were significant, with pregnancy in 8 of 30 cycles for women receiving omega-3 versus 4 in 30 for the control group. The results were even more notable for women in the overweight to obese range, with conception occurring in 8 of 27 cycles for that group versus on 1 out of 19 in the control group (Trop-Steinberg et al., 2023).
The same researchers did a review study to confirm effects of fish oil on pregnancy rates for other types of infertility, and the results indicated that fish oil supplementation produced statistically significant increases in pregnancy rates in situations beside PCOS and endometriosis. The results were consistent across multiple studies for women aged 20 to 44, and the results were seen even in the short term in studies under 12 months, with observable results within three months (Trop-Steinberg et al., 2024).
Male fertility
Omega-3 fatty acids are being used to treat male infertility as well. Fish oil supplements showed excellent results in a 2025 study that compared a group that used olive oil and a supplement containing fish oil and vitamin D against a group that used sunflower oil and a placebo. The study found that the male reproductive system is very quickly responsive to diet, with results within six weeks. The increased levels of vitamin D, EPA and DHA found in study participants resulted in beneficial effects on the genetic health of the sperm cells (Vaz et al., 2025).
Another extensive review article from 2025 confirmed that omega-3 fatty acids have a positive effect on male fertility in multiple areas. These benefits include increased energy metabolism in the sperm cells, leading to better motility. Omega-3 fatty acids also reduced oxidative stress on the sperm cells, reducing genetic errors, a beneficial effect increased by combining supplementation with vitamin E as well as vitamin D. The studies also noted that omega-3 fatty acids need to be in higher amounts than omega-6 fatty acids, which are also essential but must be in a correct ratio with omega-3 fatty acids to avoid damaging oxidative stress on the sperm. Moreover, omega-3 fatty acids play a role in cell membranes, allowing the sperm to correctly fuse with the ovum. So, the evidence for using fish oil as a help for male infertility is being repeatedly confirmed (Yang et al., 2025).
Omega-3’s
Omega-3 fatty acids are found in both fish oil and krill oil, and there is a question if one is better than the other. The omega-3 in krill oil has been found to be more bioavailable and therefore good for immediate relief of inflammatory situations, and it has been shown to be effective in smaller doses. Fish oil appears to be less bioavailable and is more effective in larger doses, but its slower breakdown provides a more stable amount in the body over time. So, they each have their place in a nutritional regime (Pham et al., 2024).
The omega-3 fatty acids in fish oil and krill oil are helpful across all aspects of health, and if sourced from a reputable company that controls for heavy metals and impurities, they are very safe. Moreover, they now can be found in pleasant flavors, such as those offered by Barlean’s company, making them one of the easier supplements to faithfully take. As with any supplement, it is advised to consult a health provider to verify that it is an appropriate supplement to add. Also, fish oil or krill oil are best used in the setting of a varied and healthy diet and accompanied by a balanced multivitamin to have the maximum influence on health and wellbeing.
Written for Family Foundations magazine by Rosemary Shannon Imrick.
Rosemary is mother to thirteen children by birth and international adoption. She homeschools her children along with her husband Michael in Fort Wayne, Indiana. A freelance writer and copy editor, she taught English Composition at Purdue University Fort Wayne for sixteen years. She now manages Shannon Haven, an agricultural business dedicated to continuing the Shannon family legacy.
Marilyn Shannon, Rosemary’s mother, wrote Fertility, Cycles and Nutrition, which also contains helpful information for optimizing male and female fertility. Find the book in the CCL store. Find more healthy recipes and information about PCOS in our book combo: Food for Fertility & PCOS.
References
Huang, Y., Zhou, W. J., Zhu, L., & Ni, D. D. (2026). Omega-3 polyunsaturated fatty acid intake and pain, inflammatory cytokines, and quality of life in endometriosis. Frontiers in Nutrition, 13, Article 1768244. https://doi.org/10.3389/fnut.2026.1768244
Liu, E., Wang, Q., Bai, Y., Zhang, X., & Wang, J. (2025). Effect of omega-3 polyunsaturated fatty acid on endometriosis. Clinics, 80, Article 100654. https://doi.org/10.1016/j.clinsp.2025.100654
Pham, T.P.T., Hoang, T.V., Cao, P.T.N., Le, T.T.D., Ho, V.T.N., Vu, T.M.H., Le, T.H.T., Pham, H.T.X., Tran, T.T., Mafruhah, O. R., Pham, T.T.L., Hsieh, M.T., & Ha, H.A. (2024). Comparison of Omega-3 polyunsaturated fatty acids bioavailability in fish oil and krill oil: Network meta-analyses. Food Chemistry: X, 24, Article 101880. https://doi.org/10.1016/j.fochx.2024.101880
Trop-Steinberg, S., Gal, M., Azar, Y., Kilav-Levin, R., & Heifetz, E. M. (2024). Effect of omega-3 supplements or diets on fertility in women: A meta-analysis. Heliyon, 10(8), Article e29324. https://doi.org/10.1016/j.heliyon.2024.e29324
Trop-Steinberg, S., Heifetz, E. M., Azar, Y., Kafka, I., Weintraub, A., & Gal, M. (2023). Omega-3 intake improves clinical pregnancy rate in polycystic ovary syndrome patients: A double-blind, randomized study. Israel Medical Association Journal, 25(2), 131–136.
Vaz, C., Burton, M., Kermack, A. J., Tan, P. F., Huan, J., Yoo, T. P. X., Donnelly, K., Wellstead, S. J., Wang, D., Fisk, H. L., Houghton, F. D., Lewis, S., Chong, Y. S., Gluckman, P. D., Cheong, Y., Macklon, N. S., Calder, P. C., Dutta, A., Godfrey, K. M., . . . Karnani, N. (2025). Short-term diet intervention comprising of olive oil, vitamin D, and omega-3 fatty acids alters the small non-coding RNA (sncRNA) landscape of human sperm. Scientific Reports, 15, Article 7790. https://doi.org/10.1038/s41598-024-83653-4
Yang, X.Y., Wei, S.Q., & Zheng, P.S. (2025). Dietary fatty acids as modulators of sperm quality: From molecular pathways to nutritional interventions. Journal of Dietary Supplements, 22(6), 870–886. https://doi.org/10.1080/19390211.2025.2539882