Salmon oil is often used to support the health of the hair, primarily due to its high content of omega-3 fatty acids, such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Scientific studies have shown that these fatty acids can have beneficial effects on skin and hair health. Research published in peer-reviewed journals indicates that supplementation with omega-3 fatty acids can improve hair density, reduce hair loss, and increase hair diameter in some individuals. The proposed mechanisms include anti-inflammatory effects, improved blood circulation to the scalp, and support of hair follicle function.

For example, a randomized controlled trial published in Journal of Cosmetic Dermatology (2015) found that women taking omega-3 and omega-6 supplements (including fish oil) experienced improved hair density and reduced telogen (resting phase) hair percentage over six months, compared to a placebo group. Other studies have shown that omega-3s may help address scalp conditions that contribute to poor hair health, such as dryness and dandruff, by supporting the skin's barrier function.

However, while evidence exists, it is moderate rather than definitive; not all individuals respond equally, and the benefits may be more pronounced in those with deficiencies or underlying inflammatory scalp conditions. Therefore, while there is scientific support for salmon oil's role in hair health, further large-scale and long-term studies are needed.