Fatty acids in skin and skin care

They feel unpleasantly greasy and oily, whether they are present as free fatty acids in candle wax or bound to glycerine as animal fat or vegetable oils. And they are unpopular as grease stains because they cannot be removed with water. None of this should be a reason not to deal with them, as they are the key to solving many skin problems once their functions are understood.

Great variety

Chemically speaking, fatty acids consist of carbon atoms (C) arranged in chains, which are bonded to hydrogen (H) and oxygen atoms (O). So, it's quite simple, isn't it? In fact, there are endless possibilities. The most important ones are:

• Saturated fatty acids such as stearic acid (candle wax) or palmitic acid (component of the skin barrier)
• Unsaturated fatty acids, which include essential fatty acids such as linoleic acid, which occur as triglycerides (glycerol esters) in vegetable oils. Oleic acid, which is a main component of olive oil, for example, is non-essential.

The term "unsaturated" means that the maximum possible number of H atoms in relation to the C atoms is not reached. The more unsaturated the fatty acids are, the more liquid and oxygen-sensitive they are. This is one reason why essential fatty acids should not be used in skin care products during the day, as they are attacked by atmospheric oxygen when exposed to sunlight.

Skin protection

As they occur as free acids in the skin barrier, palmitic and behenic acids are naturally suitable for skin protection, especially when the barrier has been damaged by intensive cleansing with surfactants. In the early days of skin care, "stearate creams" were used for this purpose, in which the fatty acids are present as sodium or potassium soaps and serve as emulsifiers in this form. The low skin pH releases the fatty acids from them. However, they leave the skin feeling dull, so later on, synthetic emulsifiers became more popular.
Fatty acids are produced from the oil phase of emulsions from the triglycerides they contain by splitting them with lipases from the epidermis and the microbiome. Mixtures with triglycerides of medium-chain fatty acids (INCI: caprylic/capric triglyceride), which are liquid in contrast to long-chain fatty acids, facilitate the production of smooth emulsions. In lamellar structures, hydrogenated phosphatidylcholine (a component of cell membranes) is used, from which fatty acids are also cleaved. Together with phytosterols and ceramides, they form the basis of effective barrier creams.

Sebum

In cases of increased sebaceous gland activity, less fatty acids and triglycerides are generally needed for skin care, as sebum already contains around 15-30% fatty acids and 30-50% triglycerides.¹ For this reason, young people tend to use "light" vegetable oils such as apricot kernel and almond oil with moderate amounts of essential fatty acids, while "mature skin" with reduced sebum production is more suited to macadamia nut oil with a high content of saturated acids and oleic acid.
The percentage of fatty acids in plant triglycerides (Table 1) is decisive for their application. It is advisable to request this data (specification) for newly offered oils and compare it with oils that have proven themselves in practice in order to ensure continuity or improvement, but preferably no disadvantages in treatment.

Problem skin

Increased production, blockage and inflammation of the sebaceous glands lead to blackheads, pimples and acne. In these cases, care with fatty acids and triglycerides should be reduced. In addition, switching to high percentages of essential fatty acids is beneficial.
This is because essential fatty acids help to normalise sebum.² In addition, their metabolites formed in the skin have an anti-inflammatory effect. Rosehip seed oil, hemp oil, kiwi seed oil and linseed oil are particularly suitable (Table 1). These oils are sometimes less than ideal for use in creams. Alternatively, they can be converted into nanodispersions together with native phosphatidylcholine, which also has a maximum content of essential acids such as linoleic and alpha-linolenic acid and at the same time acts as a penetration enhancer. They then have a consistency similar to water and are instantly absorbed into the skin.
As mentioned, essential acids are sensitive to oxygen and the skin must not be exposed to sunlight. Otherwise, radical chain reactions are triggered and counterproductive, inflammation-inducing peroxides are formed.

Atopic skin

Atopic skin requires skin protection in the form of physiologically compatible barrier creams. On the other hand, a fairly high percentage of those affected have an enzyme defect in which the gamma-linolenic acid necessary for arachidonic acid metabolism is not produced. They can be helped with topically applied evening primrose and borage oil, which contain precisely this fatty acid.
Unfortunately, this enzyme deficiency has not yet been included in dermatological laboratory screening, although a positive result and the use of appropriate care products usually make further medical treatment completely unnecessary.

Skin and nutrition

Essential omega-3 and omega-6 acids and their metabolites are both metabolised in the human organism, with the omega-3 family generally considered to be more physiologically valuable. In terms of nutrition, it has been concluded that omega-3 acids should be consumed in preference. However, this recommendation fails to recognise that the entire physiological metabolism is characterised by balances that regulate and stabilise the ratios of metabolites to each other. Only poor nutrition, which leads to a deficiency, is critical and can also affect the skin.

Cellulite

Triglycerides are fatty acids that serve as the body's energy reserve. In addition to the stored long-chain saturated fatty acids, a certain proportion of unsaturated acids in the form of oleic acid is necessary to ensure the liquid to semi-solid consistency of the fat deposits. Triglycerides are stored in the vacuoles of human fat tissue cells, i.e. in droplet form.
A certain lifestyle can lead to larger fat deposits, which, especially in women, increasingly lead to the appearance of cellulite ("orange peel skin"). Cosmetic treatments for fat deposits are generally of little effect.
In order to mobilise fat deposits for energy production, triglycerides in the body are broken down by lipases into glycerol and free fatty acids, which then enter the bloodstream. This lipolysis can be stimulated by ultrasound or shock waves and enhanced by injection solutions consisting of phosphatidylcholine (PC), deoxycholic acid (a bile acid) and water ("fat-away injection").
Sometimes, PC liposomes loaded with caffeine are used to stimulate microcirculation. Here, too, an additional external mechanical stimulus is necessary to achieve a measurable effect.³

Waxes

In waxes, long-chain fatty acids are not esterified with glycerine, but with long-chain alcohols.⁴ They have excellent skin care properties and usually have a solid consistency. Liquid jojoba oil is an exception.

Fatty acid metabolites

Details on the complex biochemistry of fatty acid metabolites, some of which have hormone-like effects, their exact chemical structures and further literature were recently published in an overview.⁵ The Beauty Forum reported specifically on the composition and use of oils extracted from nuts and other sources.^{6 7}

Table 1: Proportions of long-chain fatty acids in vegetable oils⁸

Literature

1. M. Picardo, M. Ottaviani, E. Camera and A. Mastrofrancesco, Sebaceous gland lipids, Dermatoendocrinol. 2009, 1 (2), 68–71
2. M. Ghyczy, H-P. Nissen, H. Biltz, The treat-ment of acne vulgaris by phosphatidylcholine from soybeans, with a high content of linoleic acid. J Appl Cosmetol 1996, 14, 137-145
3. H. Lautenschläger, Cellulite von A bis Z, Kosmetische Praxis 2011, 1, 10-13 and 2011, 2, 10-12
4. H. Lautenschläger, Wachse - eine unverzicht-bare Stoffklasse, Kosmetik International 2014 (10), 52-56
5. H. Lautenschläger, Langweilig oder span-nend? Eine Reise durch die Fettsäure-Chemie der Haut, Chemie in unserer Zeit 59 (2), 64-73 (2025)
6. H. Lautenschläger, Nüsse und nussähnliche Früchte, medical by Beauty Forum 2023 (4), 16-17 and 2023 (5), 14-17
7. H. Lautenschläger, Regional und nachhaltig – Hanf, Nachtkerze, Ringelblume & Co., Beauty Forum medical 2022 (2), 13-15
8. The fatty acid content may vary depending on provenance, processing and reference. The same applies to phytosterols, antioxidant vitamins and other skin care-effective accompanying substances not listed.
9. Listing limited to a few dominant representatives.

Dr Hans Lautenschläger

published in
Beauty Forum
2025 (11), 48-50