Earlier we reported on the causes and treatment of dry skin. As a result, we received a lot of questions about this and what more can be done about it. Such as the usefulness of drinking water, the usefulness of supplements and what type of moisturizers do what on, in and for the skin.
The causes of dry skin
Varying age, inclement weather conditions, low humidity due to air conditioning or heating, frequent showering and soap use. In addition, various physical conditions such as kidney function problems, delayed thyroid gland, heredity (such as atopy and ichthyosis vulgaris) and certain medications such as diuretics (hydrochlorothiazide, furosemide) for high blood pressure, isotretinoin for acne, can make the skin drier.
The effects of dry skin
The skin needs a water content between 10-15% to keep it supple and intact. Below 10% water content, dry skin is visible in the form of flakiness. When the top layer of skin, the stratum corneum, dries out further, this leads to flakes, but also to roughness and even small cracks.
W hen the dryness persists, it can even lead to asteatotic eczema. Asteatotic eczema is a non-allergic form of eczema. Most patients experience this as red, itchy, dry and scaly skin, especially on the backs of the hands and lower legs.
Does drinking water help against dry skin?
A recent article from 2018 collected many articles about this phenomenon and concluded that the hydration of the top layer of skin, the stratum corneum, did indeed improve. Exactly how the hydration process comes about is unknown. Nor is it known how much to drink.
Do supplements have any added hydrating value?
Few supplements are known to hydrate the skin. But one of them is hyaluronic acid, part of the glucosaminoglycans (GAG). Hyaluronic acid is naturally found in the second layer of the skin (dermis) and has, among other things, a water-attracting function that makes the skin feel supple and hydrated.
Several studies have shown that a hyaluronic acid supplement of 37.5 mg – 240 mg daily provided a smoother and significant skin hydration after 4 to 6 weeks.
Another supplement is collagen peptide. Collagen is the most abundant protein in the body. Collagen type 1 and to a lesser extent type 3 and GAG are both responsible for firmness and retain moisture in the skin. Two small placebo-controlled studies showed improved skin hydration with the use of a collagen peptide supplement. Both the collagen and GAG had increased in the skin after 8 weeks.
How the ingested hyaluronic acid and peptide supplements enter the skin is unknown.
What types of moisturizers are there?
There are many moisturizers on the market and they can actually be divided into 3 different categories, each with its own function.
Emollentia (space fillers) are mainly lipids and oils and fill the space between the skin cells (keratinocytes) in the upper layers of the skin. Compare it to cement between bricks. Well-known examples of this are ceramide, squalene, canola, olive, palm and coconut oil.
Important for the skin barrier
Ceramide and squalene are also made in our skin and play an important role in the skin barrier. Research shows that dry skin in the winter period is partly related to a reduced ceramide production in the skin. This leads to a disrupted skin barrier, making the skin drier.
Hormone ointment? Then use a ceramide cream with it!
Another study showed that the addition of a ceramide-containing cream in addition to a strong hormone ointment reduced symptoms, shortened disease duration and accelerated healing in patients with eczema.
Humectants (water attractors) are substances that attract water, which improves the hydration of the stratum corneum, better cohesion of the keratinocytes and reduction of scaling.
Glycerin, urea, hyaluronic acid, AHAs
Typical humectants are glycerin, sorbitol, hyaluronic acid, urea, honey and alpha hydroxy acids (AHA). Today, hyaluronic acid is in many skin care products.
Hyaluronic acid is a polysaccharide, or a long sugar that is attached to each other. A well-known example of a polysaccharide is starch. Hyaluronic acid does not dissolve in water but has a strong water-attracting effect, per gram of hyaluronic acid it can attract several liters of water.
Hyaluronic acid is naturally present in our skin and is mainly located in the dermis, the second layer of the skin, and to a lesser extent in the epidermis.
Hyaluronic acid in skin care remains in the top layer of the skin and by attracting water, the skin cells ensure better hydration of the top layer of skin.
Note: sometimes they make your skin drier
Humectants extract moisture from the skin, not moisture from the environment. This can cause more dryness and tightness in the skin for some.
Occlusives (barrier) holds moisture in the skin by physically blocking it. The TEWL is stopped by this.
Vaseline, lanolin, silicone
Examples of occlusives are Vaseline, lanolin, silicones, and waxes. 5% Vaseline very efficiently reduces the TEWL by 98% followed by lanolin, mineral oil (paraffin) and silicone which only gives a 20-30% TEWL reduction. On the skin, occlusives can feel shiny, heavy and sticky.
Asserin J, Lati E, Shioya T, Prawitt J. The effect of oral collagen peptidesupplementation on skin moisture and the dermal collagen network: evidence from an ex vivo model and randomized, placebo-controlled clinical trials. J Cosmet Dermatol. 2015;14:291-301.
Kawada C, Yoshida T, Yoshida H, et al. Ingested hyaluronan moisturizes dry skin. Nutr J. 2014;13:70.
Garibyan L, Chiou AS, Elmariah SB. Advanced aging skin and itch: addressing an unmet need. Dermatol Ther. 2013;26:92-103.