01What moisturising actually means
Skin holds water in its outermost layer, and how well it does that determines whether skin feels comfortable or tight, looks plump or dull, and behaves well or badly when shaved. Moisturising is not adding water to skin, which mostly evaporates. It is improving the outer layer's ability to hold what is already there.
That reframing explains a great deal. It explains why applying a moisturiser to damp skin works better, why occlusive products outperform light ones in cold weather, and why a product that feels wonderful for ten minutes can leave skin no better off than before. The relevant timescale is hours, not seconds.
02The three classes, and how to spot them
Humectants attract water. On a label they appear as glycerin, sodium hyaluronate or hyaluronic acid, urea, panthenol, propylene glycol, butylene glycol and sorbitol. Glycerin is the workhorse and appears near the top of an enormous share of products.
Emollients improve feel and flexibility. They appear as plant oils under Latin names, esters ending in ate, fatty alcohols such as cetyl and cetearyl alcohol, and silicones ending in cone or siloxane. Occlusives reduce water loss and appear as petrolatum, mineral oil, waxes, shea and cocoa butter and some silicones.
03The ratio is the product
A light gel moisturiser is humectant heavy with minimal occlusion. A rich winter cream is emollient and occlusive heavy. A body ointment is almost entirely occlusive. These are not different technologies, they are different proportions of the same three functions, and knowing that removes most of the mystery from a shelf.
It also predicts performance. A humectant heavy product in cold, dry, windy conditions can feel worse than nothing, because a humectant with no occlusive above it will draw water and then lose it. Men who find their skin worse after starting a light hydrating gel in January have usually met this effect rather than an allergy.
04Silicones, and the argument about them
Silicones are excellent emollients. They spread thinly, feel dry rather than greasy, reduce the appearance of texture and are well tolerated. They are also the most common target of clean beauty marketing, usually on the grounds that they suffocate skin, which they do not, being permeable to water vapour at the levels used.
The legitimate concerns about silicones are environmental rather than dermatological, and they attach to specific cyclic siloxanes rather than to the class. Those substances are handled through the chemicals regulatory regime, which is a more useful mechanism than a front of pack claim. We deal with how these arguments get flattened in chemical free and the toxicity claims.
05Petrolatum, the most effective and least fashionable
Petrolatum is among the most effective occlusives available and is used widely in dermatology, including on compromised skin. It is also the ingredient most likely to be excluded from a product positioned as natural, because it is derived from petroleum, which reads badly.
Cosmetic grade petrolatum is highly refined and is included in the ingredient lists used routinely on sensitive and eczema prone skin, which is not a position dermatology arrived at carelessly. The environmental argument about petroleum feedstocks is a real one; the safety argument is much weaker than the marketing suggests, and the two are usually presented as though they were the same argument.
06Barrier lipids and the repair idea
The skin barrier contains ceramides, cholesterol and free fatty acids in a structured arrangement. The idea behind barrier repair products is to supply those components rather than simply sealing the surface. The rationale is sound and there is a reasonable and growing body of human work, particularly in eczema prone skin.
The caution is that products vary enormously in what they contain and at what levels, and that the phrase ceramide complex on a front of pack tells you nothing about either. This is a category where the mechanism is better supported than most individual products are.
07What is different for men
Male facial skin is on average thicker and produces more sebum, which is why many men need less occlusion on the face than the category assumes and more on the neck, which is thinner and takes the shaving damage. Sebum is not the same thing as hydration, so an oily face can be dehydrated, and men often misread this and respond by using something drying.
The other male specific factor is shaving, which removes surface cells and lipids several times a week. A moisturiser is doing more repair work in a shaving routine than in a non shaving one, which is a reasonable argument for a slightly richer product than an oily skin type would otherwise choose. The interaction is covered in shaving without irritation.
08Why the price range is so wide
The three functional classes are commodity ingredients. Glycerin, fatty alcohols, common esters and petrolatum are inexpensive at formulation scale. What costs money is texture development, stability testing, elegant sensory profiles, packaging, and the marketing that surrounds all of it.
Those things have value. A product you enjoy using is a product you use, and adherence is the largest single determinant of outcome in any routine. What they do not do is change the underlying mechanism. A man paying twenty times more is buying a better experience of the same three functions, which is a legitimate purchase as long as he knows that is what it is.
09Choosing one, in three questions
- What is the weather doing? Cold and dry pushes you towards more occlusion. Warm and humid pushes you towards less.
- Where does your skin actually feel bad? Treat the neck and jawline differently from the forehead if that is where the problem is. Nothing requires one product everywhere.
- Will you use it twice a day for six months? If the texture irritates you, the formulation is irrelevant. This is the question that should decide most purchases and almost never does.