With each passing year that brings us closer to most awaited celebration and a milestone “birthday” we find ourselves increasingly investigating the skin care’s latest elixir of youth. Among the myriad serums and creams that promise plumping, moisturizing, collagen-boosting and dewy flawless skin, one standby always seems to reign: Retinol. While we are all for a magic youth facial serum, we’re also skeptical about the hype. Having heard some not-so-flattering things about retinol, including that it can make your skin itchy and dry, or even make it more susceptible to sun damage, today we will at length explain and elaborate the function, benefits, side effects as well as burst few myths and clear everyone’s doubts on Retinol.

What Exactly Are Retinoids?

Topical vitamin A-based drugs called retinoids – the most used and most studied anti-aging compounds. Tretinoin, under the brand name Retin-A, a first-generation retinoid was first used orally for the treatment of acne in 1940s.It was used as an acne treatment in the 1970s, but researchers later discovered that it also had shown promising therapeutic effects for keratinizing disorders such as actinic keratosis and ichthyosis also proven to fade pigmentation, and speeds up the turnover of superficial skin cells.

Retinol is one of the best-known skin care ingredients in the market. An over-the-counter (OTC) version of retinoids, retinols are vitamin A derivatives primarily used to treat anti-aging concerns as well as acne. That said, retinols are not the same products as prescription retinoids, which are more potent. Retinol has many potential skin care benefits, but there are few much important precautions to consider, too. Curious about whether retinol could be a beneficial addition to your skin care routine? Learn more about this key ingredient below.

Along with their beloved powers to diminish fine lines, give skin a rosy glow, and fade dark spots, retinoids also come with a million questions and concerns. One of the biggest concerns is deciphering the differences between all those R-words: retinol, retinoic acid, retinyl, etc.

1. Retinoid Esters (retinyl palmitate, retinyl acetate): weakest in the retinoid family, but a good option for beginners or sensitive skin types.
2. Retinol: has fewer side effects than retinoic acid, converts on the cellular level of the skin, thus taking several months to a year for visible results.
3. Adapalene (Differin): slows the process of excessive growth in the lining of pores and desensitizes the skin to inflammation making it an ideal treatment for acne.
4. Retinoic acid (retin-A, or tretinoin): works significantly faster than retinol since no conversion in the skin needs to take place and hence when applied directly on skin can shows the effect much quicker.

How Does It Work?

Retinoids are commonly used in cosmetic products due to their effectiveness at regulating epithelial cell growth and differentiation. Retinoids, which are lipophilic molecules, exert this effect by their ability to diffuse through cellular membranes. Once they are inside the cells, they bind to specific nuclear receptors and modulate expression of the genes involved in cellular proliferation and differentiation. Retinoids naturally occur in the skin, with retinol and retinyl esters being the most abundant form. Retinol is produced in the small intestine via one of two mechanisms: hydrolysis of retinyl esters or oxidation of carotenoids. Conversion of retinol to the active form involves oxidation to retinaldehyde, which is then oxidized to form the active tretinoin.

Genomic Actions

The genomic actions of active retinoid are mediated via binding to a cellular retinoic acid binding protein, which transports the retinoid to the nucleus. There are two recognized types, CRABP-1 and -2. CRABP-2 is highly expressed in the epidermis. Six specific nuclear retinoic acid receptors (RAR) have been found: RAR-α, -β, -γ, and the retinoid X receptors (RXR) α, β, and γ. Retinoic acid bound to an RAR directly binds to retinoic acid response elements in the DNA and modulates transcription of specific genes. The actions include prevention of matrix metalloproteinase activation, oxidative stress, and regeneration of the extracellular matrix. Retinoids also inhibit keratinocyte differentiation and stimulate epidermal hyperplasia.

Its Other Actions

Retinoids may also exert a biological effect independent of their binding to nuclear receptors. These nongenomic actions include ultraviolet (UV) absorption, as well as antimicrobial, antioxidant, and pigment activities

Ultraviolet filter
Retinoid molecules contain a side chain with conjugated double bonds that appears to absorb UV light. Animal studies have shown natural retinoids to be effective in preventing UVB-induced apoptosis and DNA photodamage. Antille et al used a retinoid vehicle (topical retinyl palmitate 2%) and sun protection factor (SPF) on the buttocks of six individuals and exposed them to UVB. In this nonrandomized small clinical trial, results showed that retinyl palmitate was as efficient as SPF 20 in preventing UVB-induced erythema and thymine dimmer formation.

Antibacterial activity
Retinaldehyde compounds are highly reactive, especially with alcohols and amines, and this may explain their antibacterial action, which is independent of nuclear receptors. Pechere et al conducted in vitro and in vivo studies investigating the antibacterial activity of retinoids. The in vitro studies showed that retinaldehyde, in comparison to retinoic acid and retinol, was the only retinoid to possess antibacterial activity. In vivo studies revealed that 0.05% retinaldehyde applied to the forehead and forearm correlated with decreases in bacterial counts when used for two weeks.

Antioxidants
In vitro studies have shown that retinoids exert free radical scavenging activity. Sorg et al showed that in hairless mice, topical retinaldehyde 0.05% prevented peroxidation of epidermal lipids when topical menadione was applied.

Pigmentation actions
Retinoids have been used as bleaching agents in certain preparations. Tretinoin, for example, has been successfully used with hydroquinone for depigmentation of skin. Yoshimura et al conducted a small, uncontrolled, nonrandomized clinical trial using 10% retinol, 5% hydroquinone, and 7% lactic acid. In their 18 patients, the authors reported good improvement in 88.9% of patients. Retinoids also are used for treatment of pigmentary disorders such as post inflammatory hyperpigmentation, melasma, and actinic lentigines.

The Benefits

1. The small molecules that make up retinol, go deep beneath the epidermis to dermis. Once in this middle layer of skin, retinol helps neutralize free radicals to boost the production of collagen and elastin. This reduces fine lines, wrinkles, and enlarged pores.

2. In psoriasis, retinoids are essential in limiting the hyperproliferation and shedding of epidermal skin cells. Also decreases inflammation and restores the normal epidermal differentiation.

3. Retinol can also help treat severe acne, as well as related scarring.

4. It helps keep pores unclogged by creating comedolytic agents to help prevent the formation of comedones or blemishes.

5. Finally, retinol has also been proven to balance skin hydration levels. Mild exfoliating effects help to remove dead skin cells that may lead to moisture loss.

6. This may even benefit oily skin by controlling excess production of sebum.

7. Since retinoids stimulate collagen production, it actually helps to thicken the skin. This is beneficial because one of the natural signs of getting older is thinning of the skin.

8. Most people assume the delicate eye area is too sensitive for retinoid use. nevertheless, this is the area where wrinkles show up first and can benefit the most from the collagen-stimulating effects of retinoids but in milder strength. If you’re sensitive around your eyes, you can always layer on an eye cream first followed by your retinoid.

If you’re interested in treating or taking preventive measures for wrinkles, fine lines, pigmentation, scarring, and more, then your late 20s or early 30s is a great age to start with an over-the-counter retinol or tretinoin. It’s around this age, that the body starts to produce less collagen, less rapidly than our earlier years. Of course, it also depends on your lifestyle and how much sun damage you have accumulated in those years! Retinoids are known for having positive effects on both aging and acne-prone skin. Retinol is the most accessible form of retinoids, as well as the best choice for sensitive skin.

The Side Effects to Note

Retinoids have so many benefits. Are there downsides and precautions to be taken?

There are definitely side effects with both retinols and retinoids, but they're temporary, lasting around three to four weeks before skin gets accustomed to it.

• People who use retinols commonly experience dry and irritated skin, redness, itchiness, and peeling skin during initial use. Possible solution is to decrease the application to every other day in a pea size and gradually build up your skin’s tolerance to retinol before moving to daily use.

• Retinoids also initially increase the skin's sensitivity to ultraviolet light. But after a few months of regular use, that sensitivity dissipates. So, all you have to do is make sure you're wearing sunscreen every day, which we should all be doing anyway.

• Retinols are NOT recommended for pregnant women. They may increase the risk for birth defects and miscarriage.

Retinoids are widely used in medicine and play a very important role in treating disease not just limited to the skin. Due to individual variability, some people may experience better overall results with the use of different retinoid therapies. It is important not to forget that overuse of this medication can lead to the development of chronic skin dryness, irritation, and discoloration. If any of these side effects are noticed, contact your physician immediately.

References
1. The Evidence Behind the Retinoids
https://academic.oup.com/asj/article/30/1/74/199813
2. A Brief Review on Systemic Retinoids
https://ijpsr.com/bft-article/a-brief-review-on-systemic-retinoids/?view=fulltext
3. Do retinoids really reduce wrinkles?
https://www.health.harvard.edu/staying-healthy/do-retinoids-really-reduce-wrinkles
4. Does retinol deserve the hype?
https://scopeblog.stanford.edu/2020/08/06/does-retinol-deserve-the-hype-a-stanford-dermatologist-weighs-in