Fish oil provides omega-3 fatty acids that support several aspects of women’s health, from pregnancy and bone density to skin quality and mood. The two active components, EPA and DHA, influence inflammation, hormone balance, and cell membrane function throughout the body. Here’s what the evidence actually shows for women at different life stages.
Pregnancy and Fetal Development
DHA is a building block of fetal brain and eye tissue, which is why demand for it spikes during pregnancy. The American Academy of Pediatrics, the March of Dimes, and the UN Food and Agriculture Organization all recommend pregnant and lactating women get at least 200 to 300 mg of DHA daily. Most prenatal vitamins include some DHA, but many fall short of that range, making a standalone fish oil supplement worth considering.
The evidence on infant outcomes is real but nuanced. A large meta-analysis published in Frontiers in Neurology found that babies whose mothers supplemented with DHA scored significantly higher on psychomotor development (physical coordination and movement skills) compared to placebo groups. The effect on mental development scores was smaller and didn’t reach statistical significance overall, though subgroup analyses of infants specifically showed stronger benefits for both mental and motor outcomes. In practical terms, DHA supplementation during pregnancy appears to give a modest but measurable boost to early physical development.
Mood and Postpartum Depression
Low omega-3 levels during and after pregnancy are linked to higher rates of depression, partly because the developing baby draws heavily on the mother’s DHA stores. Supplementation with EPA-rich fish oil can reduce depressive symptoms during pregnancy and in the postpartum period. DHA-rich supplementation given to healthy pregnant women also appears to lower the risk of postpartum depression, though the benefit doesn’t seem to extend to women who are already lactating when they start supplementing.
The timing matters. Starting fish oil during pregnancy, rather than waiting until after delivery, seems to offer stronger protection. Research suggests that EPA is the more active component for mood benefits, while DHA plays a broader role in brain structure and function. If mood support is a priority, look for a fish oil with a higher proportion of EPA.
Bone Health After Menopause
Estrogen helps protect bone density, so when levels drop after menopause, bone loss accelerates. Omega-3 fatty acids influence this process by calming the inflammatory signals that drive bone breakdown, while also supporting calcium absorption. A cross-sectional study using national health survey data found that women with higher omega-3 intake had a 35% lower likelihood of osteoporosis compared to women with low intake. The association between omega-3s and bone mineral density was modest but consistent, and stronger in women than in men.
Fish oil won’t replace the need for calcium and vitamin D, but it may complement those nutrients by reducing the chronic low-grade inflammation that erodes bone over time.
PCOS and Hormone Balance
Polycystic ovary syndrome affects an estimated 6 to 12% of women of reproductive age and involves elevated androgen (male hormone) levels, irregular periods, and often insulin resistance. In one clinical trial, women with PCOS who took 2,000 mg of omega-3 from fish oil daily for 12 weeks (alongside vitamin D) experienced a significant drop in total testosterone levels compared to the placebo group. Testosterone decreased by 0.2 ng/mL on average, while the placebo group actually saw a slight increase.
This combination approach is worth noting: fish oil paired with vitamin D may be more effective for PCOS-related hormone imbalances than either supplement alone. The research on fish oil’s independent effect on insulin sensitivity in PCOS is still limited, so it’s best viewed as a supportive tool rather than a primary treatment.
Skin Hydration and Sun Protection
Omega-3s are incorporated into cell membranes throughout the body, including skin cells, where they help maintain the barrier that keeps moisture in and irritants out. Supplementation has been shown to improve skin barrier function and reduce symptoms of dry, itchy skin in conditions like eczema and psoriasis.
There’s also a surprising connection to sun damage. One study found that taking 4 grams of fish oil daily for three months increased participants’ resistance to sunburn. Other research suggests omega-3 supplements may reduce sensitivity to UV rays and potentially lower the risk of nonmelanoma skin cancer in people who are already at elevated risk. Fish oil isn’t a substitute for sunscreen, but it appears to offer an additional layer of internal protection against UV-related skin damage.
Heart Health and Triglycerides
Heart disease is the leading cause of death in women, and omega-3 fatty acids have one of their most well-documented effects on triglycerides, a type of blood fat that raises cardiovascular risk when elevated. The American Heart Association recognizes that prescription-strength omega-3s (about 4 grams per day of EPA plus DHA) can meaningfully lower triglyceride levels. At standard supplement doses, the effect is smaller but still present.
Some oral contraceptives can interfere with this triglyceride-lowering effect, which is worth knowing if you’re taking both. The FDA allows fish oil products to carry a qualified health claim stating that EPA and DHA “may reduce the risk of coronary heart disease,” though it notes the evidence is supportive rather than conclusive. For general heart health, there’s no single recommended dose for all adults, but the FDA advises that supplement labels should not suggest more than 2 grams of EPA plus DHA per day.
Side Effects and Interactions
Fish oil is well tolerated by most people. The most common complaints are minor: fishy aftertaste, heartburn, nausea, or digestive upset. Taking capsules with food or freezing them before swallowing can reduce the fishy burps.
The more important concerns involve interactions with other medications. Fish oil has mild blood-thinning properties, so combining it with anticoagulant or antiplatelet drugs can increase bleeding risk. It can also slightly lower blood pressure, which may amplify the effect of blood pressure medications. If you take orlistat (a weight-loss drug), it can reduce absorption of omega-3s, so spacing the two about two hours apart helps. Fish oil may also gradually lower your vitamin E levels, something to watch if your intake is already marginal.
High doses (well above 2 grams of EPA plus DHA daily) carry the greatest risk of side effects, including a possible increase in stroke risk. For most women, sticking to standard supplement doses provides benefits without meaningful safety concerns.