For your skin
An essential fatty acid your sebum runs short on if you're acne-prone, and topping it up topically literally shrinks clogged pores. Also rebuilds the lipid mortar between skin cells. Found concentrated in safflower, hemp, and rosehip oils.
Want the science? Keep reading ↓Mechanism of action
Essential omega-6 fatty acid that is the sole precursor of acylceramides in the stratum corneum lipid envelope. Acne-prone skin shows low linoleate in sebum, and topical replenishment normalises follicular keratinisation, shrinking microcomedones by ~25% in 1 month.
Why we tier this moderate
4 cited papers across 3 countries. The mechanism is well-described and there's at least one controlled trial in the literature, but we tier this Moderate rather than Strong to stay honest about how many specific papers we cite directly.
Cited research
Lin TK, Zhong L, Santiago JL. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Int J Mol Sci. 2017;19(1):70. — reviews linoleic-acid-rich oils in barrier repair.
Liu M et al., Topical application of a linoleic acid-ceramide containing moisturizer exhibit therapeutic and preventive benefits for psoriasis vulgaris: a randomized controlled trial, Dermatol Ther 2015;28(6):373-82 — RCT linoleic-acid/ceramide cream improved barrier
Letawe C, Boone M, Pierard GE. Digital image analysis of the effect of topically applied linoleic acid on acne microcomedones. Clin Exp Dermatol. 1998;23(2):56-58.
Downing DT, Stewart ME, Wertz PW, Strauss JS. Essential fatty acids and acne. J Am Acad Dermatol. 1986;14(2 Pt 1):221-225.
Sources: 10 clinical journals and regulatory databases across the US, EU, Korea, Japan, and China. Every entry points to a specific document. See methodology for the full list and what each outcome label means.