Fatty acids and fat/oil supplements are commonly used to support hair health, and there is scientific evidence to justify their role. Essential fatty acids, particularly omega-3 and omega-6, are vital components of cell membranes, including those of hair follicles. Deficiencies in these nutrients have been linked to hair thinning and loss. Clinical studies have shown that supplementation with fish oil (rich in omega-3s) or other sources of polyunsaturated fatty acids can improve hair density and reduce hair loss in some populations. For example, a randomized controlled trial published in Journal of Cosmetic Dermatology (2015) found that women taking omega-3 and omega-6 supplements, along with antioxidants, experienced significant improvements in hair density and reduced telogen (resting phase) hair percentage compared to placebo.

Fatty acids may also exert anti-inflammatory effects that support scalp health, which is important for optimal hair growth. While not all proprietary blends disclose their exact ingredients or concentrations, the inclusion of well-studied fatty acids is likely aimed at leveraging these mechanisms. However, the quality and quantity of evidence varies, with most studies focusing on omega-3 and omega-6, and less robust evidence for other dietary fats. Overall, the scientific support is moderate, and supplementation is most effective in individuals with underlying deficiencies.