What Are Retinoids For Acne?
Topical retinoids for acne treatment are derived from Vitamin A. The history of retinoid use in modern day medicine dates back more than 50 years. It was first reported in 1969 that the topical retinoid, tretinoin actively treats blackheads and whiteheads (open and closed comedomes respectively), and prevents their formation in the first place. The compound 13-cis retinoic acid, otherwise known commonly as oral isotretinoin, was extensively studied in Roche Laboratories in Switzerland, and gained FDA approval in 1982 for cystic and severe acne vulgaris.
How Do Retinoids Work?
From multiple studies, it has been established that there are 4 main changes within the hair follicle and sebaceous gland unit that ultimately result in acne. There is increased sebaceous gland size (sebaceous gland hyperplasia) and activity. This hormonally mediated event explains the increased oiliness experienced by many individuals with acne. In addition, the abnormal shedding of skin cells leads to closed and open comedomes (whiteheads and blackheads respectively). This leads to an ideal environment for Cutibacterium (formerly Propionebacterium acnes) to proliferate and cause inflammation within the skin.
Retinoids for acne exert their biological effects through cellular nuclear receptors. The retinoid molecule activates the retinoic acid receptors within the cells. This increases the turnover of cells within the follicles and leads to enhanced shedding of skin. In turn, existing comedomes are expelled and microcomedomes, which are early acne lesions that are not yet visible are prevented from forming. These changes the micro-environment within the skin, making it less conducive for Cutibacterium to proliferate and cause inflammation.
Are Topical Retinoids Similar to Retinols?
Over the counter retinols are comparatively weaker in terms of their biological activity compared to retinoids prescribed by your doctor. The effects are milder and may not bring about a significant clinical change when treating a condition such as acne vulgaris. Over-the-counter retinols are in ester forms such as retinyl palmitate, retinyl linoleate, retinaldehyde, propionic acid, or retinyl acetate. These over the couter retinol products contain a much smaller concentration of active retinoic acid compared to prescription retinoids.
What Are The Types of Retinoids For Acne?
There are currently 4 different types of topical retinoids approved for acne treatment in the market. They differ in strengths (concentration), tolerability and combination with other drugs.
- Adapalene 0.1% and 0.3%
- Tazarotene 0.1%
- Tretinoin0.01%, 0.025%, 0.038%, 0.04%, 0.05%, 0.08%, and 0.1%
- Isotretinoin 0.05% and 0.1%
Retinoids may be in fixed combination with benzoyl peroxide or an antibiotic. These include:
- Epiduo (Adapalene 0.1% and Benzoyl Peroxide 2.5%)
- Clindoxyl (Clindamycin 1% and Benzoyl Peroxide 5%)
Effectiveness of Topical Retinoids For Acne
In many clinical trials, it has been proven that retinoids are effective for clearing up both comedomal and inflammatory acne vulgaris. Generally, you can expect about 70-80% improvement rate after 12 weeks of application. A fixed dose combination of Adapalene with a benzoyl peroxide such as Epiduo is superior to Adapalene monotherapy alone. While there may be an initial increase in skin irritation in the first 1-2 weeks, most of the symptoms resolved by 4-6 weeks after consistent use of the product. As acne vulgaris is considered a chronic inflammatory condition of the hair follicle and sebaceous gland unit, a retinoid based treatment shows sustained improvement even beyond 12 months.
Besides treating active acne and preventing the formation of new acne, topical retinoids have shown to improve scarring and post-inflammatory hyperpigmentation. A study conducted using Adapalene 0.3% showed an improvement in 1 to 2 scar grades and skin texture after 24 weeks. Retinoids improve post-inflammatory hyperpigmentation by increasing skin cell turnover and reducing melanin transfer to skin cells.
What Are The Side Effects of Retinoids?
The tolerability of retinoids depend on skin type, vehicle (gel or cream), concentration and the type of retinoid. Individuals with sensitive skin (history of skin irritation with facial and cosmetic products) tend to have more irritation with retinoids. Generally, the best tolerated gel is Adapalene and the best tolerated cream is Tazarotene.
It is common to experience mild to moderate degrees of skin redness, peeling, irritation and dryness within the first 1-2 weeks of starting your retinoid therapy which will eventually subside. These changes occur in the first 1-2 weeks during the normal shedding process as skin cells become less glued to each other and their arrangement is lost. Subsequently, the skin cells are re-arranged, less peeling and irritation occurs. Tretinoin 0.05% resulted in 60% of individuals experiencing some skin irritation compared with 19% irritation rate with Adapalene 0.1%.
How Do I Apply Retinoids?
As you can tell, topical retinods are higly effective in treating and preventing new acne. However, the issue of tolerability can cause discomfort and may stop some individuals from continuing treatment. Here are some tips that helps to ease you into your acne treatment journey:
- Awareness that mild irritation is common, and will subside within 1-2 weeks.
- Start with a pea size (or even half a pea size) amount and apply thinly to the affected areas.
- Avoid exfoliation and over-cleansing. Use a gentle cleanser.
- Apply our topical retinoids gradually. Start with every 3rd day for the first 2 weeks, then alternate day on the 3rd and 4th week. Once there is no irritation, apply nightly for best effect.
- Apply a gentle moisturizer that is non-comedogenic.
Which Is The Best Retinoid For Acne?
In a recent study, it has been shown that the differences between the retinoids are minor. More important than choosing the type of retinoid, is what type of retinoids work best at a particular concentration. Topical adapalene showed the best tolerability among all the retinoids. A fixed combination Adapalene with Benzoyl peroxide is superior compared to monotherapy and is well tolerated in majority of individuals.
- Kolli, S.S., Pecone, D., Pona, A. et al. Topical Retinoids in Acne Vulgaris: A Systematic Review. Am J Clin Dermatol (2019). https://doi.org/10.1007/s40257-019-00423-z.
- Culp L, Moradi Tuchayi S, Alinia H, Feldman SR. Tolerability of topical retinoids: are there clinically meaningful differences among topical retinoids? J Cutan Med Surg. 2015;19:530–8.
- Dunlap FE, Baker MD, Plott RT, Verschoore M. Adapalene 0.1% gel has low skin irritation potential even when applied immediately after washing. Br J Dermatol. 1998;139(Suppl 52):23–5.
- Leyden, J., Stein-Gold, L. & Weiss, J. Why topical retinoids are mainstay of therapy for acne. Dermatol Ther (Heidelb) (2017) 7: 293.
- Grimes P, Callender V. Tazarotene cream for postinflammatory hyperpigmentation and acne vulgaris in darker skin: a double-blind, randomized, vehicle-controlled study. Cutis. 2006;77:45–50.
- Patel M, Leung S, Chien AL, Xu H, Audibert F, Kerrouche N, Rueda MJ, Kang S. Improvement in atrophic acne scars by topical adapalene 0.3% gel is associated with induction of procollagen I and III. Society of Investigative Dermatology. Albuquerque, NM2014.