Linoleic Acid

Probiotics in skincare refer to live microorganisms, their lysates, fermentation byproducts, or cell-free extracts that confer a benefit to the skin by modulating the cutaneous microbiome and immune response. The human skin harbors a diverse community of bacteria, fungi, and viruses collectively known as the skin microbiome, which plays a critical role in barrier defense, immune regulation, and protection against pathogenic colonization. Topical probiotics work by reinforcing the populations of beneficial commensal organisms, producing antimicrobial peptides such as bacteriocins, and modulating toll-like receptor signaling to reduce excessive inflammatory responses. Common probiotic species used in skincare include Lactobacillus, Bifidobacterium, and Streptococcus thermophilus, often delivered as ferment lysates or filtrates for improved stability.

Hemp seed oil is a lightweight, non-comedogenic plant oil extracted from the seeds of Cannabis sativa. It is exceptionally rich in polyunsaturated fatty acids, containing an optimal omega-6 to omega-3 ratio of approximately 3:1, which closely mirrors the lipid profile of healthy human skin. The oil is composed of roughly 55-60% linoleic acid, 15-20% alpha-linolenic acid, and 10-15% oleic acid, along with gamma-linolenic acid (GLA), a rare anti-inflammatory fatty acid. Hemp seed oil also contains tocopherols (vitamin E), phytosterols, and trace amounts of carotenoids and minerals. Its molecular structure allows for rapid absorption without leaving a greasy residue, making it suitable for a wide range of skin types including oily and acne-prone complexions. Unlike CBD oil, hemp seed oil is derived exclusively from seeds and contains negligible levels of cannabinoids.

Sea buckthorn oil is a vibrant orange-red oil derived from the berries and seeds of the Hippophae rhamnoides shrub, a hardy plant native to the coastal and mountainous regions of Europe and Asia. Two distinct oils are obtained from this plant: the seed oil, which is lighter in color and rich in alpha-linolenic and linoleic acids, and the fruit/berry oil, which is deeply pigmented due to exceptionally high concentrations of carotenoids, particularly beta-carotene and lycopene. Both forms are extraordinarily rich in bioactive compounds including vitamins A, C, E, and K, flavonoids, phytosterols, and the rare palmitoleic acid (omega-7), which is a major component of human skin lipids and plays a critical role in cell signaling and wound healing. Sea buckthorn oil is one of the few plant sources of all four omega fatty acids (3, 6, 7, and 9), making it one of the most nutritionally complete botanical oils available for topical skincare.

Sunflower seed oil is a widely available, cost-effective plant oil expressed from the seeds of Helianthus annuus. The high-linoleic variety, which is the type most valued for skincare, contains approximately 60-72% linoleic acid, 15-20% oleic acid, and smaller amounts of palmitic and stearic acids. It is one of the most well-studied plant oils for dermatological use, with robust clinical evidence supporting its barrier-repairing and anti-inflammatory properties. Sunflower seed oil is naturally rich in vitamin E (primarily alpha-tocopherol), phospholipids, and lecithin, all of which contribute to its emollient and skin-protective effects. Its light texture, neutral scent, and excellent spreadability make it a staple ingredient in moisturizers, cleansing oils, and baby skincare products. It is also frequently used as a carrier oil for essential oils and other active botanical extracts.

Olive oil is one of the oldest known oils used in human skincare, with documented use dating back to ancient Egyptian, Greek, and Roman civilizations. It is pressed from the fruit of the Olea europaea tree and is composed predominantly of oleic acid (65-80%), with smaller amounts of palmitic acid (7-14%), linoleic acid (4-12%), and stearic acid (1-4%). Extra virgin olive oil (EVOO) retains the highest concentration of bioactive phenolic compounds, including hydroxytyrosol, oleuropein, oleocanthal, and tyrosol, which are among the most potent natural antioxidants ever studied. Hydroxytyrosol in particular has an ORAC value estimated to be 10 times that of green tea catechins. The oil also contains squalene (up to 0.7%), phytosterols, and fat-soluble vitamins A, D, E, and K. Despite its long history, modern dermatological research has revealed a more nuanced picture of olive oil's suitability for topical use, particularly regarding its potential to disrupt skin barrier function in certain individuals.