Dehydrocholesterol

7-dehydrocholesterol occurs naturally in the skin and plays an important role as a precursor in the biosynthesis of cholesterol and vitamin D3. For its conversion to vitamin D3 or calcitriol, 7-dehydrocholesterol requires sunlight in the UVB wavelengths with peaks at 270, 280 and 295nm.
7-dehydrocholesterol, vitamin D3 and calcitriol are involved in complex processes in the skin. They have important functions for the protective cell envelope, the skin barrier, regulate cell differentiation, stimulate the skin’s own antimicrobial peptides, protect against damage from UV rays, have a regulating effect on skin pigmentation and protect the hair follicles.

In the skin, 7-dehydrocholesterol is found in the highest concentrations in the epidermis, specifically in the stratum basale and stratum spinosum, which are the areas of cell regeneration that are rich in moisture. This suggests that it plays an important role in the formation and differentiation of corneocytes.
A lack of sunlight can lead to a vitamin D deficiency. In addition, the amount of 7-dehydrocholesterol decreases with age. Dry, blemished, prematurely ageing, light-sensitive skin can be an expression of a deficiency, as well as acne, psoriasis and neurodermatitis.

The external application of 7-dehydrocholesterol as a precursor of vitamin D formation in skin care products has many benefits. As a skin-affine substance, it is well absorbed. One advantage is that it is only converted into calcitriol up to a certain saturation point, after which it is broken down. It supports the absorption of hydrophobic substances into the stratum corneum and strengthens the condition of the skin and hair. It also has emulsifying properties. The effects of 7-dehydrocholesterol and calcitriol have been proven in many studies.

Cell differentiation

Calcitriol is involved in the differentiation and regulation of the growth of keratinocytes. Studies show that it regulates the hyperproliferation that is typical of diseases such as psoriasis. It has an antiproliferative effect and, on the other hand, promotes the differentiation of cells.
It has been shown to influence the epidermal calcium gradient, which plays a role in cell differentiation and the formation of the skin barrier. The calcium level is lowest in the basal layer and highest in the granular layer. The cells of the granular layer contain a precursor of keratin, keratin hyalin, and have reached an advanced stage of cornification. Calcium and calcitriol regulate keratinocyte differentiation and stimulate involucrin, a protein involved in the formation of the protective cell envelope and the skin barrier.

7-dehydrocholesterol is also directly involved in the formation of the horny protective layer of the skin and in the maturation process of the corneocytes, without the conversion to vitamin D. If this process is carried out properly and completely, it is accompanied by the production of sufficient natural moisturising factors (NMF).

Antimicrobial peptides

Calcitriol supports the function of antimicrobial peptides in the skin, such as defensins and cathelicidins, and activates the toll-like receptor (TLR), which is also part of the innate immune system. Unconverted 7-dehydrocholesterol can also increase TLR expression.
While cathelicidin expression is reduced in atopic dermatitis and eczema, it is increased in rosacea and psoriasis, where it promotes inflammatory processes. 7-dehydrocholesterol can relieve acne and protect follicles from inflammation due to its regulatory influence on antimicrobial peptides.

Light damage

Skin cells react to harmful influences with repair mechanisms such as the formation of heat shock proteins. These help the other proteins to fold correctly into their active three-dimensional structure, thus ensuring the survival of the cells. The external application of 7-dehydrocholesterol can increase the amount of proteins and mRNA responsible for the formation of heat shock proteins. This increases the minimum dose of UVB radiation that the skin can be exposed to before an erythema occurs. The skin is more resistant and better protected against light damage.

Pigmentation

Studies have shown that the repigmentation of vitiligo is possible with external vitamin D3 applications. It regulates the supply of tyrosinase for melanogenesis and restores calcium homeostasis and calcium flow into melanocytes.

Hair follicles

The loss or inactivity of vitamin D3 receptors (VDR) leads to thinning hair or hair loss. Studies on the hair cycle in mice have shown that VDR expression in hair follicles is stronger in the anagen and catagen phases than in the early anagen and telogen phases, and is therefore correlated with reduced proliferation and increased differentiation of keratinocytes.

Mode of action

While it was long assumed that calcitriol required transcription processes mediated by the vitamin D3 receptor in the cell nucleus to achieve biological responses, it is now known that this VDR is not only in the cell nucleus, otherwise the rapid responses would not be explainable. It is also found in the indentations of the cell membranes, so-called caveolae, in many, almost all organs of the body.

Profile

INCI: 7-Dehydrocholesterol

CAS No.: 434-16-2

Formula: C27H44O

Trade name/manufacturer: TEGO® Sterol 7-DHC and TEGO® Sterol 7-DHC V / Evonik;

MMP Europe: INCI: 7-Dehydro cholesterol, trade name: Skin’ential DC;

Labio Co., Ltd.: INCI: Glycerin, Methyl Cyclodextrin, Aqua, 7-Dehydrocholesterol, trade name: Auqa-pro Vita D3

Description: cholesterol molecule, a precursor in the biosynthesis of cholesterol and vitamin D 3, cream-coloured solid, soluble in organic solvents, active ingredients 100%

Production: semi-synthetic, starting material: sustainably produced sheep’s wool

Effect: naturally enhances the skin’s own protective functions, regulates cell differentiation, stimulates the skin’s natural antimicrobial peptides, can protect against damage against UV radiation

Use in cosmetics: moisturising cream, protective and anti-ageing products, repair care, pigment-balancing formulations, sun protection products, after-sun products, facial toner, cleansing, decorative cosmetics, bath and shower products, deodorants, hair care, special products for acne, dermatitis, rosacea, neurodermatitis mitis

Recommended concentration for use: 0.5

Boosting the skin’s natural powers

Since vitamin D3 metabolism in the skin starts with 7-dehydrocholesterol, the external application of this skin-affinity molecule has a positive influence on the entire skin and enables it to utilise the entire spectrum of calcitriol effects.

It is about strengthening the skin barrier and the skin immune system, as well as well-aging and skin balance. 7-dehydrocholesterol is so versatile in skin care and cosmetics that Cosmacon considers it a pleasure to work with this interesting active ingredient. If you would like to have your own cosmetics produced with this active ingredient, you have come to the right place.

Literature:

New Approach to Develop Optimized Sunscreens that Enable Cutaneous Vitamin D Formation with Minimal Erythema Risk

Dieter Kockott,  Bernd Herzog, Jörg Reichrath, Kevin Keane, Michael F Holick

PLoS One. 2016 Jan 29;11(1):e0145509

https://pubmed.ncbi.nlm.nih.gov/26824688/