What is Differin?
Differin is a topical acne treatment which contains a synthetic retinoid called adapalene. Adapalene is considered to be a third-generation retinoid and it’s actually fairly different in chemical structure when compared to tretinoin (Retin-A) or other retinoic acid compounds. However, like other synthetic retinoids like tazarotene (Tazorac), adapalene activates the same receptor targets in the skin like retinoic acid receptor (RAR) β and γ and retinoid X receptor (RXR). Adapalene is more stable than tretinoin and can be used in with benzoyl peroxide. It is also more lipophilic (fat “loving”), so more can accumulate within the sebaceous unit.
Differin for Acne
When compared head to head, 0.1% adapalene gel was more effective than a 0.025% tretinoin gel in non-inflammatory (open and closed comedones) and inflammatory (papules and pustules) acne. A multi-ethnic study (Chinese, Malaysian, Indian, and Caucasian) found that it was well tolerated (which means less irritation) among all races. A separate study on Black South Africans also found efficacy in treating acne while maintaining good tolerability. A meta-analysis, which included 5 studies, compared 0.1% adapalene gel and 0.025% tretinoin gel and found them similarly effective for acne. Of particular interest to acne sufferers, it appears that adapalene begins to reduce acne after 1 week of use, which is faster than tretinoin and may be due to the reduction in irritation. Considering that irritation (redness, dry skin) is a common complaint of my patients when beginning retinoids, another study showed that 0.1% adapalene gel was less irritating than 0.1%, 0.05%, 0.025% tretinoin and even 0.1% tretinoin microspheres (Retin-A Micro). A study comparing 0.03% and 0.1% adapalene gel found that the 0.1% adapalene gel was significantly more effective than the 0.03% gel in treating acne, which is great since this is the strength recently approved for OTC use. There was also a supplementary article submitted to Cutis (peer-reviewed clinical journal) that reported a decrease in sebum production in subjects that were using 0.1% adapalene gel for 4 weeks. Sebum production returned to normal after the treatment was stopped. This possible mechanism by which adapalene is thought to reduce sebum production is by suppressing triglyceride formation in sebocytes.
Differin for Hyperpigmentation
Adapalene appears to also be effective in treating hyperpigmentation, however there is considerably more research (and evidence) supporting tretinoin and tazarotene. A non-blinded study on 65 Black African patients using a 0.1% adapalene gel found significant improvements in hyperpigmentation. Additionally, less than 5% of subjects in the study experienced skin irritation.
Differin for Anti-Aging
With regards to treating photodamage and photoaging, there is not much data in the literature on the topic, especially compared to tretinoin and to a lesser extent tazarotene. There was however a study performed by Galderma that looked at 0.1% and 0.3% adapalene gel on 90 Caucasian subjects which noted improvement in solar lentigines (sun spots) and actinic keratosis (AK’s). The dermatologists performing the study also noticed an improvement in fine skin wrinkles and an overall brightening of the skin. However, there were no significant change in deep wrinkles. Results were much more pronounced with the 0.3% adapalene gel. Another Galderma study on Chilean women found similar results. Researchers noted marked improvement in skin wrinkling at both 90 and 180 days of treatment using a Visia skin analyzer (google this machine, super cool!), though they did not differentiate between fine and deep wrinkles. Of particular interest to me was that skin thickness did not increase, which is common with tretinoin treatment, however they did find an improvement in abnormal elastin accumulation (elastosis band) in the skin, which is always nice to see.
So by now you might be thinking, “This stuff sounds great, why am I not using this already?” Great question! First and foremost, your first stop for anything skin-related should be to a board-certified Dermatologist for a proper evaluation (shameless plug for myself). This doesn’t mean that you aren’t able to help treat yourself with OTC medications, because there are many great ones on the market, but nothing can replace the advice, training, and experience of a Dermatologist. However, this does mean that consumers have yet another highly effective tool in their skin armamentarium for treating acne (as well as other skin conditions) that was previously only available through prescription.
-The Skin Doc