TL;DR: Differin gel was prescription-only for twenty years. In 2016 the FDA moved adapalene 0.1 percent gel to over-the-counter status with almost no industry press. It is the only third-generation retinoid available without a prescription. It has roughly the efficacy of tretinoin 0.025 percent with substantially better tolerability data. The retinol industry would prefer you did not know this exists.
A reader emailed me last year asking which retinol percentage she should buy. She had been comparing 0.5 percent and 1 percent serums priced between $40 and $90. She wanted to know if the higher number was worth the extra forty dollars.
I asked her if she had considered Differin. Adapalene gel 0.1 percent. Twelve dollars at the CVS down the street.
She had not. She had spent three months researching retinol serums and nobody on the skincare forums she was reading had mentioned that the FDA approved a prescription-strength third-generation retinoid for OTC sale in 2016 and the cosmetic industry never quite acknowledged it.
This is the article she asked me to write.
What adapalene is
Adapalene is a synthetic third-generation retinoid. It was developed by Galderma in the 1990s as an alternative to tretinoin with better photostability, lower irritation, and selective binding to specific retinoic acid receptors. It binds primarily to RAR-β and RAR-γ, the two receptors most involved in skin cell differentiation, and largely skips RAR-α, which is implicated in some of the irritation response from older retinoids (Czernielewski et al., Journal of the European Academy of Dermatology and Venereology, 2001).
It was approved as a prescription topical for acne in 1996. For twenty years it remained Rx-only in the United States, available as Differin gel and a few branded combinations. Then in July 2016 the FDA reclassified adapalene 0.1 percent gel as available without prescription. The reasoning, in the FDA’s own documentation, was that the safety profile in the published clinical record was strong enough that supervised access was no longer necessary.
The cosmetic retinol market did not advertise this change. It would have been bad for sales of products that were less effective and twice as expensive.
How adapalene compares to tretinoin
This is the comparison people search for most. Adapalene 0.1 percent has been studied head-to-head with tretinoin 0.025 percent multiple times. The Cunliffe et al. 1998 trial in the British Journal of Dermatology, which is the one most often cited, found roughly equivalent efficacy on inflammatory and non-inflammatory acne lesions after twelve weeks, with adapalene producing significantly less erythema and dryness.
The Thielitz 2008 review consolidated about a dozen trials and reached the same conclusion. Equivalent on outcomes. Better tolerated.
What this means in practice is that if you are deciding between adapalene 0.1 percent OTC and tretinoin 0.025 percent prescription, the adapalene will be slightly less irritating, easier to introduce, and roughly equal in result. The tretinoin advantage starts at 0.05 percent and above, where the comparison gets more complicated.
How adapalene compares to OTC retinol
This is the comparison the industry does not want to make.
Retinol is a precursor to retinoic acid. When you apply retinol topically, your skin enzymes convert it to retinaldehyde, then to retinoic acid. The conversion is inefficient. The published estimates are that approximately 5 to 10 percent of applied retinol reaches the active retinoic acid form in the skin, with significant variation by individual skin enzyme activity.
This means a 1 percent retinol product is delivering, in active terms, roughly 0.05 to 0.1 percent equivalent retinoic acid. A 0.3 percent retinol is delivering maybe 0.015 to 0.03 percent equivalent.
Adapalene at 0.1 percent is already a retinoic acid analogue. There is no conversion step. Every molecule that crosses the corneum is biologically active at the receptor.
This is why adapalene gel at $12 outperforms most retinol serums at $60. The cheaper product is the active form. The serums are precursors with inefficient conversion.
There are some retinoid serums that bypass this problem. Retinaldehyde products like Avene Retrinal or some of the Korean retinal products are one conversion step closer to the active. Granactive retinoid, also called hydroxypinacolone retinoate, is a different ester with stronger receptor affinity. These are reasonable. The standard 1 percent retinol formulations are not competitive with adapalene 0.1 percent on either efficacy or price.
The data on non-acne use
Adapalene was approved for acne. Its use for other indications, like photoaging and hyperpigmentation, is technically off-label. The data exists.
Bagatin et al. published a trial in 2018 comparing adapalene 0.3 percent to tretinoin 0.05 percent for photoaging over 24 weeks. The results were comparable on wrinkle depth and pigment measures, with adapalene again showing better tolerance. The Tan 2020 review in American Journal of Clinical Dermatology covers adapalene’s role in atrophic acne scar prevention and finds it works at the dermal collagen remodelling level the same way tretinoin does.
This is the same mechanism people are paying for in retinol serums marketed as anti-aging. Adapalene does it for $12.
The reason adapalene is not marketed for anti-aging is regulatory. Galderma’s approval is for acne. Marketing it for wrinkles would require new regulatory submissions. The cosmetic retinol market is not subject to that constraint, which is why it can make ambiguous wrinkle claims that a regulated drug cannot.
How I have used it
I started adapalene in 2020 on the recommendation of a dermatologist who I was paying $250 a visit to and who told me I could skip the prescription tretinoin and use OTC Differin. She said she used it herself.
I applied it three nights a week for the first six weeks. Pea-sized amount across the whole face after moisturiser, what is called the sandwich method to reduce irritation. After six weeks I moved to every other night. After three months I was on it nightly.
The retinisation period, the initial weeks where the skin adjusts and you get some peeling, lasted about three weeks for me. Less than I had with my previous tretinoin trial. I had some dryness, no significant peeling, and one minor purge of three blackheads that surfaced and resolved.
I have used it for five years now. My skin texture is the smoothest it has been since my early twenties. My acne is gone, and my fine lines around the eyes are stable, which at 40 is what I am hoping for. I have spent maybe $150 on it total over five years, including the periodic switches between Differin gel and the generic adapalene 0.1 percent that costs $9 at Costco.
The 1 percent question
When somebody asks me if a 1 percent retinol is stronger than a 0.5 percent retinol, the honest answer is that the percentage tells you almost nothing without information about the delivery system, the stability of the formulation, the pH, and the conversion enzymes in your individual skin.
This is the retinol percentage scam. The number on the label is a marketing variable, not a clinical one. A 1 percent retinol in an unstable formulation that has been on the shelf for eight months is delivering less active than a 0.3 percent retinol in an airless pump with antioxidant stabilisation.
The brands that take this seriously, like Medik8 or some of the L’Oreal-owned dermatological lines, will publish stability data and delivery information. Most do not. The number on the front of the bottle is doing the work the data should be doing.
Adapalene at 0.1 percent has no equivalent ambiguity. The percentage refers to the active molecule. The formulation is FDA-regulated for content. The product on the shelf today is the product that was tested in trials.
The contrarian section: when to choose retinol over adapalene
Adapalene is not for everyone. Two contexts where retinol or retinal makes more sense.
First, pregnancy or trying to conceive. Adapalene is category C. Most dermatologists pause topical retinoids in pregnancy. Retinol esters at low concentrations are sometimes considered, though the safer move is bakuchiol or nothing for the duration.
Second, very sensitive or rosacea-prone skin. Some readers cannot tolerate even adapalene’s reduced irritation profile. Retinaldehyde at 0.05 percent in a soothing formulation can be a gentler entry point. The Avene Retrinal product line is the most studied in this niche.
If neither of these applies and the goal is efficacy per dollar, adapalene wins on the data we have.
What I do now
Differin 0.1 percent gel, pea-sized, nightly, applied 20 minutes after my moisturiser. No retinol serum. No retinal serum. I have not bought a retinol product in five years. The Differin tube lasts about three months and costs $12.
If you cannot tolerate the nightly use, the sandwich method (moisturiser, wait, adapalene, wait, moisturiser again) is well-tolerated by most people and is what every Korean and French dermatologist I have asked recommends as the introduction protocol.
Frequently asked
Why is adapalene cheaper than retinol if it works better? Because it went off-patent and the FDA approved generic OTC versions. Retinol is sold by the cosmetic industry, which has higher margins and more marketing spend. Adapalene is sold by Galderma and a handful of generics at near-commodity prices.
Is adapalene 0.3 percent worth the upgrade? It is prescription-only and slightly more effective for acne. For non-acne use the 0.1 percent OTC is enough for most people. Talk to a dermatologist if you want the 0.3 percent.
Can I use adapalene with vitamin C or acids? Adapalene is more pH-stable than tretinoin and tolerates evening application after a morning vitamin C serum. Direct combination with AHAs in the same routine increases irritation. I avoid acids on adapalene nights and use them on the off nights if I use them at all.
How long until I see results? Twelve weeks for acne. Six months for texture. A year for fine lines. This is the same timeline as tretinoin. Anyone selling faster results is selling something else.
Closing
The retinol market is a marketing structure that grew up because adapalene was prescription-only for two decades and the cosmetic industry needed a category to sell. The FDA changed the regulation in 2016. The marketing did not change because the marketing was making more money than the regulation update was costing.
The reader I started this article with switched to Differin. She paid $12. Six months later she emailed a comparison photo with her last $80 retinol bottle next to her current $12 tube. The results were not subtle.
If you are starting out with retinoids, this is the entry point. If you have been using retinol for years and feeling unsure why your results are modest, this is the swap to try.
Linked tools: the retinol strength comparison, the tretinoin decoder, and the skin cycling calculator for working out a tolerance schedule.
References
- Thielitz A, Abdel-Naser MB, Fluhr JW, Zouboulis CC, Gollnick H. Topical retinoids in acne – an evidence-based overview. Journal der Deutschen Dermatologischen Gesellschaft, 2008. PMID: 18983432.
- Czernielewski J, Michel S, Bouclier M, Baker M, Hensby JC. Adapalene biochemistry and the evolution of a new topical retinoid for treatment of acne. Journal of the European Academy of Dermatology and Venereology, 2001. PMID: 11843230.
- Cunliffe WJ, Poncet M, Loesche C, Verschoore M. A comparison of the efficacy and tolerability of adapalene 0.1% gel versus tretinoin 0.025% gel in patients with acne vulgaris. British Journal of Dermatology, 1998. PMID: 9892884.
- Tan J, Tanghetti E, Baldwin H, Stein Gold L, Lain E. The role of topical retinoids in prevention and treatment of atrophic acne scarring. American Journal of Clinical Dermatology, 2020. PMID: 32514835.
Related Elelaf tools
Sources
- Thielitz A, Abdel-Naser MB, Fluhr JW, Zouboulis CC, Gollnick H. Topical retinoids in acne – an evidence-based overview. Journal der Deutschen Dermatologischen Gesellschaft, 2008. PMID: 18983432.
- Czernielewski J, Michel S, Bouclier M, Baker M, Hensby JC. Adapalene biochemistry and the evolution of a new topical retinoid for treatment of acne. Journal of the European Academy of Dermatology and Venereology, 2001. PMID: 11843230.
- Cunliffe WJ, Poncet M, Loesche C, Verschoore M. A comparison of the efficacy and tolerability of adapalene 0.1% gel versus tretinoin 0.025% gel in patients with acne vulgaris. British Journal of Dermatology, 1998. PMID: 9892884.
- Tan J, Tanghetti E, Baldwin H, Stein Gold L, Lain E. The role of topical retinoids in prevention and treatment of atrophic acne scarring. American Journal of Clinical Dermatology, 2020. PMID: 32514835.