Ingredient in lotion: Moisturizers: Do they work? – Harvard Health
Moisturizers: Do they work? – Harvard Health
There are lots of dubious claims and mysterious ingredients, but yes, by trapping water, moisturizing can help with dry skin.
Dry skin by itself isn’t a medical worry, although serious cases can result in cracks and fissures that invite infection and inflammation. The real issue is discomfort — dry skin can be sore, tender to the touch, and often itchy (although not all itchy skin is dry). There’s also the red, rough, scaly appearance lamented in many advertisements for moisturizers.
This is one problem that hasn’t suffered from lack of attention: there are dozens of creams and lotions for dry skin. They are sold as moisturizers, which is more of a marketing term than a medical or scientific one. Indeed, routine skin care is a realm where there’s little science to be found. Well-controlled studies of ingredients are few and far between. Companies keep information about ingredients proprietary and are careful to limit claims for what the products do to stay within FDA rules.
But sales people learned ages ago that science sells, so labels and ads often use scientific terms. Moisturizers are often billed as hypoallergenic or “allergy tested” — even though there’s no government standard for making such a claim, so any product can do so. Some products brag about being noncomedogenic — an impressive word that means they won’t cause pimples — but that’s not saying much: almost all moisturizers on the market today use ingredients that are noncomedogenic. Lists of vitamins are supposed to get us thinking that moisturizers can nourish skin or stoke it full of antioxidants. Yet in most cases vitamins in moisturizers probably don’t make much difference, either because the amounts used are too small to have much effect, or because the vitamins degrade with exposure to light and oxygen.
The fact is that despite the long lists of obscure ingredients and the pseudoscientific hokum, all moisturizers help with dry skin for a pretty simple reason: they supply a little bit of water to the skin and contain a greasy substance that holds it in. In fact, if greasiness weren’t a problem, we might all go back to using the solution for dry skin that our grandparents used: 100% white petrolatum, which most of us know as Vaseline. One reason for the proliferation of moisturizers is the continuing search for a mix of ingredients that holds in water like petrolatum but feels nicer on the skin. Many products also contain humectants (pronounced hue-MEK-tants), ingredients that sponge up and retain water.
The good news is that despite all the unknowns and salesmanship, you really can’t go very wrong with what moisturizer you choose. Almost all the moisturizers on the market will help with dry skin, and in most cases, the choice comes down to subjective experience — and simply whether you like the feel and smell (nothing wrong with that — it’s your skin, after all). You want to choose one you like and use it regularly.
6 tips for those with dry skin
Dead cells on top
Take a look at the drawings below, and you’ll see that our skin is organized in layers. The outermost one is called the stratum corneum, which consists of cells called corneocytes and various lipids — fats — between them. The corneocytes are often compared to bricks and the intercellular lipids to mortar, an appropriate metaphor for a layer of skin that serves as a barrier, but the stratum corneum looks more to us like phyllo, the thin sheets of dough used to make baklava.
The corneocytes are dead cells without nuclei, but they aren’t just deadwood. They contain various substances that hold water. For our skin to feel smooth and supple the stratum corneum has to be at least 10% water; ideally, it’s 20% to 30%. The stratum corneum can absorb as much as five to six times its own weight and increase its volume threefold when soaked in water. But it’s not simply the water content that matters. It’s the effect that water has on the enzymes that control orderly shedding of corneocytes, a process dermatologists call desquamation. Without water, the corneocytes accumulate, so skin becomes flaky instead of peeling off nicely, and the stratum corneum gets disorganized and full of cracks instead of being tightly packed.
Because moisturizers contain oil, it’s a common misconception that they are replacing lost oil. But most young children have wonderfully smooth skin, and the sebaceous glands in the skin don’t start producing oily sebum until puberty. Dry skin is about lack of water, not oil.
Occlusives hold water in after it has been supplied either by the moisturizer or a soak in water.
Humectants sponge up water, drawing it up from the dermis and, to a limited extent, in humid conditions, from the air.
Emollients fill in rough spots and make skin feel smooth but don’t affect the water content.
Ingredients in moisturizers
Water. Most moisturizers are oil-in-water emulsions, so by definition that makes them creams and lotions. Look at the ingredient list, and you’ll see that water is often the first one. Some of the water evaporates when you apply the moisturizer, but some also soaks in. While the stratum corneum absorbs water nicely, it doesn’t bind it very well, so some oily substance is needed to hold it in. Applying an oily substance to the skin without also resupplying it with water — either from the moisturizer or from another outside source like a bath — is ineffective: you’d just end up with greasy skin that is still dry and cracked. In fact, the optimum way to soften skin is to soak it thoroughly first in water and then cover it with something like Vaseline. But that’s time-consuming and messy so unless your skin is extremely dry, using a moisturizer that contains water is much easier and more practical.
Occlusives. Petrolatum and the other oily substances in moisturizers are sometimes referred to as occlusives because they block the evaporation of water. Despite all the elaborate variations in moisturizers, petrolatum is still a mainstay and is often named third or fourth in the ingredient list. Many fatty or waxy substances can serve as occlusives. The commonly used ones include cetyl alcohol (a fatty alcohol), lanolin, lecithin, mineral oil, paraffin, and stearic acid. Dimethicone and cyclomethicone are silicones that function as occlusives. When products say they are oil-free, that usually means they don’t contain mineral or vegetable oil and depend on dimethicone as an occlusive instead. The Aveeno products tout their “natural” oatmeal content, but in some varieties, the only active ingredient listed is dimethicone. The effectiveness of the occlusives varies. Petrolatum is the best at holding in water, followed by lanolin, mineral oil, and the silicones.
Humectants. Theoretically, humectants pull water into the stratum corneum both from the air and from deeper layers of the skin. However, when the humidity is low, there’s so little water in the air that almost all of the water comes from the inside out. Some of the commonly used humectants include glycerin, honey, panthenol (or vitamin B5, an example of a vitamin being used for its physical, not nutritional, properties), sorbitol (which we are used to seeing as an artificial sweetener), and urea. Humectants can potentially make skin even drier by pulling water into a damaged, arid stratum corneum that doesn’t hold moisturizer. So, as a practical matter, they are almost always used with occlusive ingredients that trap the moisture the humectants draw into the stratum corneum.
Emollients. Emollients aren’t in moisturizers to moisturize, but rather to make the skin feel smooth. Many ingredients that serve as occlusives — dimethicone is a good example — and humectants do double duty as emollients. Because of rubbing alcohol (isopropyl alcohol), we tend to think of alcohols as drying — and out of place in moisturizers. But some alcohols (octyldodecanol, for example) are excellent emollients.
Vitamins. Topical retinoic acid — a form of vitamin A — reduces fine lines and wrinkles in the skin by stimulating the production of collagen and is the main ingredient in prescription antiwrinkle creams. But the vitamin A used in some moisturizers is retinyl palmitate, which has the virtue of being a very stable molecule but isn’t nearly as biologically active as retinoic acid. It’s unlikely that retinyl palmitate in the amounts found in moisturizers has much, if any, effect on collagen and wrinkles. If retinyl palmitate has a benefit, it may be as a humectant.
Vitamin C, usually under the name ascorbic acid, and vitamin E, usually as tocopheryl acetate, are added because of their antioxidant properties. Studies of topical vitamin C have shown some effects, but in high concentrations. Doubts linger about its usefulness in moisturizers because light and oxygen inactivate the vitamin C. Vitamin E as tocopheryl acetate is biologically inactive and probably functions mainly as a preservative.
Menthol. Moisturizers that bill themselves as itch remedies like Sarna often contain menthol. Although menthol doesn’t attack the underlying problem, the familiar cooling sensation does seem to cancel out the itching sensation.
Lactic acid. Skin over the heel can get especially thick, leathery, and dry. Try using a pumice stone or callus file to get rid of the outer layers of skin and then using a moisturizer like AmLactin to soften it up. AmLactin, an over-the-counter lotion, is 12% lactic acid, a heavy-duty humectant that can also loosen up adhesions so heel skin becomes more flexible and less likely to crack. Sometimes products containing lactic acid sting.
Image: © HongChan001 | Dreamstime.com
Lotion Ingredient Glossary | Whole Elise
It can be a little tricky getting a handle on all the different terms and ingredients used in lotion recipes, here is a glossary for all the common components that you’ll need to make a lotion. Think of this as a “cheat sheet” or helpful companion guide to making lotions.
For a full tutorial with step-by-step instructions, check out my beginner’s guide to lotion-making.
“Diluent” and “solvent”. Water is used to dissolve other water-soluble ingredients like gums, clays and botanical extracts in lotions.
Water also provides hydration to the skin, it gives moisture to the upper layers of the skin helping to keep it plump and supple.
This is the crucial difference between emulsified moisturisers like creams and lotions, compared to anhydrous products such as body butters and balms. Water-based ingredients also require preservatives to prevent the growth of bacteria, fungus and mould.
In lotions, water can take many forms including:
- Aloe Vera Juice / Gel
- Botanical Extracts, e.g. Green Tea Extract
- Floral Waters & Hydrosols, e. g. Chamomile Flower Water
Humectants attract water from the surrounding atmosphere, replenishing your skin and hair’s moisture levels.
Some humectants also form a protective thin film on the surface of the skin to prevent further moisture loss. Humectants are essential components of lotions as they contribute to keeping your skin hydrated throughout the day.
Popular humectants in lotions include:
- Glycerine and Honey
- Hyaluronic acid
- Panthenol (Vitamin B5)
- Hydroyzed proteins, e.g. Keratin Protein
- Sodium lactate
Emollients lubricate, soften and smooth the surface of your skin by restoring lipids to the upper layers of the epidermis.
Skin lacking in lipids (oils) can appear dry, dull and rough, emollients bolster your skin’s natural barrier for healthier, more supple skin.
Oil and butters are popular emollients used in natural lotions, but there are a variety of emollients that can be used in creams and lotions:
- Natural triglycerides – carrier oils and butters such as coconut oil, olive oil, safflower oil, and shea butter, mango butter and cocoa butter
- Fatty acids and alcohols – fatty acids (lauric, caprylic, stearic acid) are components of carrier oils but can be bought separately, whilst fatty alcohols (cetyl alcohol, and cetearyl alcohol) are made from reacting fatty acids with hydrogen.
- Esters – such as coco-caprylate/caprate, caprylic/capric triglyceride are formed from combining organic acids with alcohol or glycerine
Emulsifiers combine oil and water together in a lotion to form a stable mixture (emulsion). They are surfactants that possess both hydrophilic (water-loving) and hydrophobic (water-fearing or oil-loving) elements.
Emulsifiers can be both solid or liquid and take on a variety of appearances including flakes, powders, pellets and liquid.
Despite the name, emulsifying waxes are not actual “waxes”, they’re solid emulsifiers commonly used in cream and lotion products. They are typically made of two or more emulsifying agents, and commonly contain fatty alcohol to increase the stability of an emulsion. An emulsifier can also be labelled “complete” or “self-emulsifying” which refers to its ability to form an emulsion by itself or whether it requires a “co-emulsifier” to help create a stable lotion. Emulsifying waxes often contain thickeners that are far more likely to determine the texture of your finished lotion compared to oils and butters.
Please note: beeswax is not an emulsifier. It is commonly confused or mislabelled as an “emulsifier” likely because it works as a stabiliser and thickener, but by itself, it is unable to bind oil and water molecules together.
Not all emulsifying waxes are made from natural or naturally-derived ingredients, below are a list of common emulsifiers of natural origin.
- Olivem 1000 or Olive-derived Emulsifying Wax (INCI: Cetearyl Olivate, Sorbitan Olivate)
- Montanov 68 / Vegetal (INCI: Cetearyl Alcohol and Cetearyl Glucoside)
- ECOMulse / NatraMulse (INCI: Glyceryl Stearate, Cetearyl Alcohol and Sodium Stearoyl Lactylate)
- Emulsan II (INCI: Methyl Glucose Sesquistearate)
- Natragem EW/Ecomuls (INCI: Glyceryl Stearate, Polyglyceryl-6 Palmitate / Succinate and Cetearyl Alcohol)
- Simulgreen 18-2 (INCI: Hydroxystearyl Alcohol and Hydroxystearyl Glucoside)
Thickeners & Stabilisers
Thickeners improve the sensory properties of a lotion, making it easier and more luxurious to use. In addition to adjusting the texture, thickeners also provide stability to the lotion by increasing the viscosity reducing the separation of water and oil molecules. This leads to a more stable emulsion that is more likely to hold up to temperature and environmental changes over time.
This is why thickeners and stabilisers are often used interchangeably in lotions – often time the same ingredient will both thicken and stabilise your lotion.
There are different types of thickeners for both the oil and water phase of a lotion: aqueous and non-aqueous. Typically lotion formulas will use both types to ensure maximum stability.
- Natural aqueous thickeners (water-based): originate from plants, microbial or animal sources. Examples include xanthan gum, guar gum, casein, and clays.
- Natural non-aqueous thickeners (oil-based): waxes such as beeswax, soy, candelilla wax are popular ingredients in lotions. These can be confused with emulsifiers, but they only work to stabilise an already emulsified lotion – they themselves aren’t emulsifiers. Fatty alcohols (e.g. cetyl alcohol and cetearyl alcohol) are also common oil-based thickeners and stabilisers.
- Synthetic thickeners: synthetic polymers such as polyethylene glycols, PEGs or PEG derivatives are very effective thickeners that produce far more stable emulsions. They are of course not natural and are therefore not used in organic products.
Preservatives are essential for all lotions as they prevent the growth of microbes, bacteria, mould, fungus and yeast. Without the use of preservatives, cosmetic products will spoil and become potentially hazardous to the skin.
The determining factor in whether to use a preservative is the presence of water.
If a product either contains water (including water-based ingredients) or will come in contact with water (handled or applied with wet fingers e.g. scrubs) a preservative is mandatory.
There are different types of preservatives that combat specific issues, however to ensure that your lotion has full coverage against all bacteria, mould, fungi and yeast you will need to use a Broad Spectrum preservative.
The effectiveness of a preservative can be reduced dramatically depending on a number of factors including the usage rates, whether it’s oil or water-soluble, the pH value or the temperature of your lotion when it’s applied. It’s important to check the manufacturer’s instructions and follow them strictly when applying your preservative.
Examples of natural preservatives
- Preservative Eco / Mikrokill ECT / Geogard ECT / Plantaserv M – (INCI: Benzyl Alcohol, Salicylic Acid, Glycerine and Sorbic Acid)
- Geogard 221 / Cosgard – (INCI: Benzyl Alcohol and Dehydroacetic Acid)
- Naticide / Plantaserv Q – (INCI: Fragrance or Parfum)
- Geogard Ultra – (INCI: Gluconolactone and Sodium Benzoate)
- Phenethyl Alcohol – (INCI: Phenethyl Alcohol)
Please note: Vitamin E Oil is an antioxidant, not a preservative. It will not protect your creams and lotion from bacteria, mould, fungus or yeast.
Antioxidants have two main functions in lotion:
- Protect skin cells from “free radical” damage
- Prevent against oxidation and thus lengthen the shelf-live of the oils in your lotion
It’s the second function of antioxidants that make them essential to include in your lotion formulas. Exposure to air can onset the natural process of oxidation in oils, this can cause rancidity that can ultimately cause irritation and harm when applied to the skin.
Antioxidants like vitamin E and Rosemary extract slow down the oxidation process.
- Vitamin E refers to a group of compounds called Tocopherols. You can find vitamin E as a single molecule or “mixed tocopherols”. Generally mixed tocopherol vitamin E oils provide more protection against oxidation. “Tocopherol acetate” is a synthetic vitamin E oil that protects the skin from free radical damage, but does not prevent oxidation.
- Rosemary extract is an excellent antioxidant but can have a strong scent so might not be suitable in all lotions.
Vinotherapist™ Nourishing Hyaluronic Acid Body Lotion | CAUDALIE®
- Hyaluronic acid
: 100% natural biotechnological product: smoothes the skin and gives it long-term hydration by acting on its upper layers.
- Organic shea butter
: Organic 100% natural, produced in Burkina Faso in a sustainable manner. The oil nourishes, regenerates and restores dry skin. 100% natural organic product, produced in Burkina Faso in accordance with the principles of sustainable development. The oil nourishes, regenerates and restores dry skin.
: Derived from the seeds of French grapes, polyphenols have antioxidant properties and completely block free radicals.
List of all ingredients:
AQUA/WATER/EAU, COCO CAPRYLATE/CAPRATE, GLYCERIN, VITIS VINIFERA (GRAPE) FRUIT WATER, BUTYROSPERMUM PARKII (SHEA) BUTTER EXTRACT, CANDELILLA/JOJOBA/RICE BRAN POLYGLYCERYL-3
ESTERS, GLYCERYL STEARATE, PALMITOYL GRAPE SEED EXTRACT, CETEARYL ALCOHOL, SODIUM STEAROYL
LACTYLATE, SACCHARIDE ISOMERATE, CAPRYLYL GLYCOL, XANTHAN GUM, POTASSIUM SORBATE, ACRYLATES/C10-30 ALKYL ACRYLATE CROSSPOLYMER, LIMONENE, LINALOOL, VITIS VINIFERA (GRAPE) JUICE, TOCOPHEROL, HELIANTHUS ANNUUS (SUNFLOWER) SEED OIL, CITRIC ACID, SODIUM PHYTATE , GERANIOL, SODIUM HYALURONATE, SODIUM HYDROXIDE, SODIUM BENZOATE, SODIUM CITRATE, PARFUM (FRAGRANCE), CITRAL. (227/071)
Not listed0034 Free of: parabens, phenoxyethanol, phthalates, triclosan, triclocarban, beta-hydroxy acids, resins, 1,4-dioxane, formaldehyde formaldehyde releasing preservatives (quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea, polyoxymethylene urea, sodium hydroxymethylglycinate , 2-bromo-2-nitropropane-1,3-diol, glyoxal, methenamine, 5-bromo-5-nitro-1,3-dioxane, 1-nitropropane, formalin, methanal, methylaldehyde, methylene oxide, paraformaldehyde), bisphenol A (BPS), ethyl acrylate, tetrahydrofurfuryl methacrylate, trimethylol propane trimethyl acrylate, carbon black, lead, lead acetate, mercury and its derivatives (thimerosal), toluene, acrylamide, bromostyrene, styrene and styrene oxide, nitromusk.