Retinol

One of the most famous and well-researched anti-aging ingredients. It is proven to decrease wrinkles, help the skin to regain its thickness, firmness, and texture. Retinol is also proven to effectively treat pigmentation issues such as dark spots and acne.
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Retinol

Overview

Retinol is one of the most famous skincare and dermatological anti-aging ingredients. Before we dive into the many different benefits (and pitfalls) of retinol in skincare, let's clarify some terminology first.

Retinol simply means vitamin A. This vitamin A can take on several different forms in our body, all equally active. Retinol itself is considered a transport form of vitamin A, traveling through our bloodstream to places where it's needed.

In its final destination, like, for example, in skin cells, retinol is oxidized into the active form of vitamin A in two steps: first to retinal and then to retinoic acid. Tretinoin is another name for retinoic acid and is also a molecule used frequently in medications (along with its derivative, isotretinoin).

Retinol esters such as retinyl palmitate are a storage form of vitamin A - our liver and skin in particular are capable of creating a small stash of vitamin A for later use. Retinol and retinol esters are better tolerated than tretinoin. They are less potent and must be used in somewhat higher concentrations to achieve the same results.

All of these forms can jointly be called retinoids. This also includes several artificially made molecules that also have vitamin A activity: granactive retinoid/hydroxypinacolone retinoate, adapalene, and others.

Now that we know what the retinoids are, let's talk about what they do for our skin. Vitamin A has several extremely important functions in our body, including for our vision, the proper function of our immune cells, and general cell division.

For skin, the most important part is its function in general cell division. Our epidermis consists of cells that divide often, and the topmost layers of cells slowly die and peel away. Older or sun-damaged skin can have this process disrupted in several ways.

At first, the skin may become thick, leathery, coarse, and dried out. In the later stages of skin damage, the skin cells die out and the skin becomes thin, wrinkled, and fragile. The best way to prevent this is by protecting yourself with sunscreen.

Retinol has been shown to fix some of the effects of aging and sun damage, but only to an extent. In clinical studies performed on real human volunteers, 0,4% retinol cream produced notable results after only 7 days. The epidermis increased in thickness, there was more collagen and elastin in the skin, and the skin was less wrinkled and better supplied with blood.

In another study, two different concentrations of retinol in serum form - 0,15% and 0,3% - produced positive effects after 4 and 8 weeks. The study reported fewer wrinkles, better hydration, and skin radiance.

The longest study lasted a whole year. 0,1% retinol improved crow's feet fine lines by 44%, and pigmentation by 84%. From these studies, we can safely conclude that retinol helps the skin to regain its thickness, firmness, and pleasant texture.

It is also known to help with pigmentation issues such as dark spots and acne scars. Acne itself also responds well to retinol therapy, although there are other retinoids better suited for acne treatment, such as adapalene and tretinoin. These are usually prescribed by a dermatologist.

Concentrations of 1% or stronger are restricted for physician use only. A 3% retinol peel was found to be effective against wrinkles, acne, and melasma, and was suitable for skin of color.

It is important to note that while retinol may have many incredible benefits, it also comes with a catch. It is very prone to oxidation, especially when the molecules are exposed to sunlight. The packaging of your retinol product should be opaque and air-tight (e.g. non-see-through pump bottle) and your skin should be protected from sunlight during and after use.

Some experts recommend retinol for nighttime use only, but if you remember to protect yourself with sunscreen then you are free to use it any time.

The reaction of your skin to retinol depends on its concentration and the sensitivity of your skin. Concentrations higher than 0,3% can sometimes cause redness, burning, and irritation.

Retinol increases the cell turnover in your skin, so you might see some initial breakouts and peeling until your skin gets used to it. If this happens, try using a lower concentration. In the studies referenced above, the researchers rarely saw signs of irritation in concentrations below 0,3-0,4%.

One of the most frequently asked questions is whether retinol can be combined with other powerful anti-aging ingredients. The answer is complicated and depends entirely on the concentration, formulation, and skin sensitivity.

Studies have shown that retinol in combination with AHAs or vitamin C is not only safe, but beneficial, and produces better results than retinol alone. Keep in mind that AHAs are exfoliating ingredients and that the combination may cause excessive peeling and flaking. It is better to take it slowly and gradually.

Salicylic acid and benzoyl peroxide are often used alongside retinoids in acne treatment, but these combinations can be irritating and so if your skin reacts badly, it may be better to use them at different times of the day, or on alternating days. The same goes for procedures such as laser therapy or microneedling.

Retinoids in pill form must under no circumstances be used during pregnancy and breastfeeding. The danger is not as clear as with retinol in cream form, but for the safety of the baby, it is best to avoid it just in case.

Science

1
Riahi, R. R., Bush, A. E., & Cohen, P. R. (2016). Topical Retinoids: Therapeutic Mechanisms in the Treatment of Photodamaged Skin. American journal of clinical dermatology, 17(3), 265–276.
2
Shao, Y., He, T., Fisher, G. J., Voorhees, J. J., & Quan, T. (2017). Molecular basis of retinol anti-ageing properties in naturally aged human skin in vivo. International journal of cosmetic science, 39(1), 56–65.
3
Zasada, M., & Budzisz, E. (2020). Randomized parallel control trial checking the efficacy and impact of two concentrations of retinol in the original formula on the aging skin condition: Pilot study. Journal of cosmetic dermatology, 19(2), 437–443.
4
Randhawa, M., Rossetti, D., Leyden, J. J., Fantasia, J., Zeichner, J., Cula, G. O., Southall, M., & Tucker-Samaras, S. (2015). One-year topical stabilized retinol treatment improves photodamaged skin in a double-blind, vehicle-controlled trial. Journal of drugs in dermatology : JDD, 14(3), 271–280.
5
Sadick, N., Edison, B. L., John, G., Bohnert, K. L., & Green, B. (2019). An Advanced, Physician-Strength Retinol Peel Improves Signs of Aging and Acne Across a Range of Skin Types Including Melasma and Skin of Color. Journal of drugs in dermatology : JDD, 18(9), 918–923.
6
McDaniel, D. H., Mazur, C., Wortzman, M. S., & Nelson, D. B. (2017). Efficacy and tolerability of a double-conjugated retinoid cream vs 1.0% retinol cream or 0.025% tretinoin cream in subjects with mild to severe photoaging. Journal of cosmetic dermatology, 16(4), 542–548.
7
Wójcik, A., Bartnicka, E., Namieciński, P., & Rotsztejn, H. (2015). Influence of the complex of retinol-vitamin C on skin surface lipids. Journal of cosmetic dermatology, 14(2), 92–99.
8
Kligman, D. E., & Draelos, Z. D. (2016). Combination Superficial Peels With Salicylic Acid and Post-Peel Retinoids. Journal of drugs in dermatology : JDD, 15(4), 442–450.
9
Veraldi, S., Rossi, L. C., & Barbareschi, M. (2016). Are topical retinoids teratogenic?. Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia, 151(6), 700–705.