Phytosterols: everything you need to know about this category of active ingredients.

The phytosterols are found in a wide variety of plants. They are obtained by purifying the oil extracted from these plants. Among the main sources of phytosterols, we find soybean oil, corn oil, sunflower oil and rapeseed oil. These oils contain different phytosterols such as beta-sitosterol, campesterol and stigmasterol, all three having soothing and repairing properties for the skin.

Some fruits such as avocados and certain berries, in addition to their vitamin and antioxidant content, also contain phytosterols. Finally, these can be found in whole grains like oats, wheat, and brown rice. By combining the phytosterols from these various plants, it is possible to create a cosmetic treatment capable of caring for sensitive skin and scalps.

Regarded as very gentle active ingredients, phytosterols are often incorporated into treatments for sensitive, irritated or dry skin or scalps. Their use for skin or hair care has numerous benefits.

• Moisturisers : phytosterols have the ability to capture and retain water, making them good humectant agents. The topical application of these compounds supports the hydrolipidic film present on the surface of the epidermis and helps to limit insensible water loss, or TEWL.

• Repairers : Phytosterols stimulate the activity of fibroblast growth factor, the fibres responsible for the synthesis of collagen and elastin, which are essential for the formation of scar tissue. They can thus help the skin to recover following a minor injury or acne.

• Anti-inflammatories : Phytosterols have the ability to inhibit the activity of COX and LOX, inflammatory enzymes that release prostaglandins, as well as the action of certain pro-inflammatory cytokines. Therefore, phytosterols can be used to soothe skin or scalp itching or certain redness.

• Prevention of ageing signs : a study has shown that certain phytosterols can inhibit collagenase, the enzyme responsible for the breakdown of collagen 's peptide bonds and its degradation. The action of phytosterols on collagenase helps to prevent this phenomenon and contributes to skin suppleness.

• Antioxidants : Phytosterols protect the skin against free radicals, thus contributing to the slowing down of skin ageing. They also protect the hair from the appearance of split ends or breakage.

• Antibacterials : It has been demonstrated that β-sitosterol acts against Staphylococcus aureus, a Gram-positive bacteria. This active ingredient can help regulate the bacterial populations living on our skin.

To date, no side effects have been reported after using phytosterols for cosmetic purposes. This ingredient is considered safe and is not subject to a concentration limit by European cosmetic regulations, although it is generally incorporated into skincare products at a concentration less than 5%. It's also worth noting that these plant compounds are not among the cosmetic actives advised against during a pregnancy or breastfeeding and they are suitable for children from the age of 3 years.

Note : we are only discussing here the topical use of phytosterols. The oral intake of phytosterol-based medications is regulated and, if you need to resort to it, it is necessary to strictly follow your doctor's recommendations.