Linolenic Acid
Linolenic acid (alpha-linolenic acid, ALA) is an omega-3 polyunsaturated fatty acid (PUFA) with three double bonds, giving it a liquid consistency. It is an essential fatty acid that the human body cannot synthesize and must obtain from dietary sources such as leafy greens, walnuts, flax seeds, and fish oils. In cosmetics, it is classified as a skin-identical ingredient and functions as an emollient, surfactant/cleansing agent, and skin conditioner per CosIng.
ALA's primary role in the skin is modulating the immune response of the epidermis, which may be beneficial for inflammatory skin conditions such as atopic dermatitis and acne. One study found that topically applied ALA has spot-fading (hyperpigmentation-lightening) abilities. It is also considered probably moisturizing and anti-inflammatory as a skin-identical ingredient, though its topical effects are less established than those of linoleic acid.
Most supporting research examines ALA as an oral supplement rather than a topical ingredient, so topical efficacy is less established. Its role and effects when applied to skin appear less direct compared to linoleic acid.
