Retinoids - What are they and what are they doing in cosmetics?

What are retinoids?

Retinoids are substances related to retinol, which itself is a derivative of A vitamins. They are found in animal and plant products, and are essential for humans^[1].

What is Retinol, and what is its job?

Fig. 1 The structure of retinol

Retinol is a so-called β-ionone, and belongs to the A vitamins. These are responsible for the growth and functioning of the skin, mucous membranes, blood cells and bone tissue, as well as metabolism, vision and the biosynthesis of testosterone and estrogen [2].

What are retinoids chemically?

The retinoids differ in three generations:

1. The non-aromatic e.g. Tretinoin - the retinoic acid

- This occurs in acne treatment. And is also used as an adjunct to the treatment of acute myeloid leukemia (AML - blood cancer). However, it can lead to an increase in intracranial pressure and pulmonary edema. These side effects have a lethality of 10%, with the cure rate of AML being 80%.

2. The mono-aromatic e.g. acitretin

- This is used in the treatment of psoriasis and cornification

3. poly-aromatic e.g. adapalene

-This is used as an acne remedy and can cause redness, irritation and dehydration, but is better tolerated than tretinoin

All are descendants of the retinol and thus of the β-ionone. Jonons are already noticeable to humans from a very low concentration, and usually have floral odors. They are especially in berries, tea and tobacco before.

What do retinoids do in cosmetics?

In cosmetics, retinoids are often used against wrinkles, and they actually help after some studies [4]. However, it is quite common that the skin can be irritated and reddened when first used, this effect should even be expected. However, if the side effects do not disappear after 4-5 days, you should stop using the product [5].

Sources:

Wikipedia^[1][2][3][5]

Scientific report on the effect of retinoids on skin aging^[4]