Retinaldehyde or retinal (with an A!) has become the latest, buzz-worthy retinoid on the market. Many seasoned retinoid users are honing in on the fact that in the process of retinoic acid synthesis, retinal would be the more efficient (aka more potent) cosmetic retinoid compared to retinol in getting those sweet anti-aging benefits. You might even hear retinal claims such as “10x more effective than retinol” or even “tretinoin strength without the tretinoin irritation.” Bold claims!
While retinal isn’t the newest kid on the block, its entry into skincare feels like its only just beginning. In this retinal guide, we’ll go over what retinal is, do these bold claims hold up, and who should be using retinal in their routine.
What’s the difference between retinal vs retinol?
Think of retinal and retinol as closely related molecular cousins. Both of the molecules are in the retinoid family and are key molecules in the retinoic acid synthesis pathway.
Retinal is one step closer than retinol to converting to the retinoic acid form that your skin’s retinoic acid receptors can interact with to kick off all those anti-aging processes. On the other hand, retinol has to go through a 2 step-conversion. It’s because of this shortened process, that retinal in theory, should be much more powerful than retinol. However, like all things skin science, there are caveats.
You might be wondering, “Well if retinal is so much better than retinol, why did we bother with retinol in the first place? How did retinol become more popular than retinal?” The industry insider secret is, retinal is notoriously unstable. Yes, we’ve voiced before that RetinOL is already a fussy ingredient to work with (review our retinol guide here), but retinal is actually even worse. It’s so bad that historically, papers that looked at retinal stability would run tests on a 24 hour timeframe. This definitely wouldn’t be long enough to last in a jar let alone survive 2 to 3 months of product use. Retinol stability can be challenging as well, but it is at least stable enough for chemists to carefully formulate with it and ensure retinol products can deliver the skin benefits you want.
However, we should mention that with recent advances in encapsulation technology, retinal stability is slowly changing. We have seen a few recent papers that study protecting retinal in various encapsulation techniques to help stabilize it for just long enough for skincare applications. Some even get really complex. For example, this one group in Korea published a study in 2022 on their encapsulation technique, where they synthesized not just ONE layer of encapsulation but TWO layers and found that retinal is significantly more stable double-dumpling-wrapped than au naturel.
*Degradation amount after 24hrs. Note the 24 hour time scale… retinal really hates being stable!
It’s promising to see all of this encapsulation work being done to help functionalize retinal for skincare use. But, before we hop on board the retinal hype train, we still need to look at the performance data. Just because retinal can be more stable, doesn’t mean that it can actually perform and provide those benefits we’re looking for. Is retinal really 10x more powerful? How does retinal compare to tretinoin or retinol? Let’s look at the evidence!
What concentration of retinal works?
Unlike other established retinoids, retinal percentage isn’t actually quite dialed in yet. Based on the retinoid pathway, you should need, in theory, something higher than tretinoin’s 0.01% to 0.1% but lower than retinol’s 0.1% to 1%. Good news! There’s a clinical study we can look at.
In one study, 40 volunteers were split into two groups. One group used a 0.05% retinal cream for 3 months, while the other group used a 0.1% retinal cream for 3 months. Every 4 weeks, the volunteers are evaluated for TEWL (transepidermal water loss), fine wrinkles, melanin index, and skin roughness.
For both groups, the creams were effective at improving all parameters, though not to a statistically significant degree (this could be due to the relatively small study size). What is notable is that the 2 groups (0.05% & 0.01%) performed on par with no statistical difference between the two. The only parameter where 0.1% retinal had definitively outperformed the 0.05% group was in melanin index.
All in all, this early-phase study shows that retinal does… something.
Retinal vs Retinol - Is retinal really 10x more effective?
Luckily, we were able to find one paper published recently in 2021 that performed a 1:1 comparison of retinal to retinol. A Korean research group had 23 subjects apply retinal on one side of the face and retinol on the other side of the face for 2 months. For the first 4 weeks, volunteers used 0.05% retinal and 0.05% retinol. Then, from week 5 to 8, the concentrations of retinal and retinol were increased to 0.1%. Subjects were evaluated at the 4 week and 8 week mark for key skin parameters such as wrinkle depth, skin hydration, and skin elasticity.
This is a good but early look at what encapsulated retinal can do for skin. However! Keep in mind that 0.05%/0.1% retinal was tested to be on par with retinol at the exact same percentage. This is a far cry from the claim that retinal is “10x more effective than retinol”, and the comparison to retinol isn’t the most applicable since retinol is typically used between 0.1%-1.0%.
How to find the best retinal serum for your skin?
Major brownie points to products with clinical studies!
All in all, based on available evidence, it’s still slightly early for us to be super excited about retinal just yet. Definitely be wary of overstated claims like “tretinoin-level efficacy” or “10x better than retinol”. That said, everyone’s retinoid journey is unique. If you want to try it for yourself, we’d definitely recommend brands that have done clinicals on their retinal formulation. Because retinal is notoriously finicky and formulation-dependent, clinicals can provide insightful data on how the product will perform. Both Avene and Peach & Lily are two brands that have conducted studies on their retinal serum. We’d say these are great places to start.
Is the retinal encapsulated?
There aren’t enough antioxidants you could add or airtight packaging you could use that could save a non-encapsulated retinal from its fate of rapid degradation. What makes things even more complicated is that it can be really difficult to scan an ingredient list to figure out if a retinal is encapsulated or not. Look for mentions of encapsulation in the product description, or you can simply ask the brand directly!
What % retinal do I need?
Based on studies so far, you should target a serum with at least 0.05% retinal. If your skin has a history of tolerating retinoids well, you can even aim for a 0.1%. At this point, we aren’t able to equate any retinal %s to retinol %s quite yet.
Sources
Lidén, M., & Eriksson, U. (2006). Understanding retinol metabolism: structure and function of retinol dehydrogenases. Journal of Biological Chemistry, 281(19), 13001-13004.
Pechere, M., Pechère, J. C., Siegenthaler, G., Germanier, L., & Saurat, J. H. (1999). Antibacterial activity of retinaldehyde against Propionibacterium acnes. Dermatology, 199(Suppl. 1), 29-31.
Bailly, J., Crettaz, M., Schifflers, M. H., & Marty, J. P. (1998). In vitro metabolism by human skin and fibroblasts of retinol, retinal and retinoic acid. Experimental dermatology, 7(1), 27-34.
Ha, J. H., Choi, H., Hong, I. K., Han, S. K., & Bin, B. H. (2022). Study on Stabilization of Retinaldehyde using Drug-in-Cyclodextrinin-Liposome (DCL) for Skin Wrinkle Improvement. Journal of the Society of Cosmetic Scientists of Korea, 48(1), 77-85.
Kwon, H. S., Lee, J. H., Kim, G. M., & Bae, J. M. (2018). Efficacy and safety of retinaldehyde 0.1% and 0.05% creams used to treat photoaged skin: A randomized double‐blind controlled trial. Journal of cosmetic dermatology, 17(3), 471-476.
Kim, J., Kim, J., Jongudomsombat, T., Kim BS, E., Suk, J., Lee, D., & Lee, J. H. (2021). The efficacy and safety of multilamellar vesicle containing retinaldehyde: A double‐blinded, randomized, split‐face controlled study. Journal of cosmetic dermatology, 20(9), 2874-2879.
