The Retinoid Family
By now you've probably heard of retinoids — a family of Vitamin A derivatives — and their amazing skin benefits. The most famous retinoids in skincare are retinol (spelled with an O), retinaldehyde (also known as retinAl), and retinoic acid (also known as tretinoin or Retin-A, available by prescription only).
How Conversion Works
Out of these three retinoids, only retinoic acid has a direct effect on our skin cells. Retinol and retinaldehyde must first be converted into retinoic acid in order to work — and that conversion happens through enzymes.
Retinol is two steps removed from retinoic acid, while retinaldehyde is just one step removed. The key reason retinol is so much weaker is that the first conversion — retinol becoming retinaldehyde — is inefficient. Think of it like trying to FaceTime over a really bad cell signal: not a lot gets through.
However, the conversion step that turns retinaldehyde into retinoic acid is efficient — like FaceTiming over strong WiFi or 5G. Everything gets through. That one fewer conversion step is what makes retinaldehyde roughly ten times more powerful than retinol.
Retinaldehyde is approximately 10× more potent than retinol because it's only one enzymatic conversion step away from retinoic acid — and that conversion step is highly efficient.
Potency vs. Gentleness
As amazing as retinoids are, they can also cause irritation for some people. This is where retinaldehyde really shines: despite its high potency, it's relatively very gentle. It is almost as powerful as prescription-only tretinoin, but with significantly less irritation. There is a lot of scientific research and evidence behind this — we go into depth in our Deep Guide to Retinoids.
The Acne Bonus
There is an additional attribute that sets retinaldehyde apart from both retinol and retinoic acid: retinaldehyde can kill acne-causing bacteria.
A 1999 study by Pechere and colleagues found a significant reduction in bacterial population when skin was treated with retinaldehyde — a property unique among retinoids.
Retinaldehyde has demonstrated antibacterial activity against Propionibacterium acnes — the bacteria responsible for breakouts. This is a property that neither retinol nor retinoic acid shares.
So if treating and preventing acne is your main goal, retinaldehyde is especially compelling: retinoids in general help treat acne, and retinaldehyde itself is uniquely capable of targeting the bacteria that cause it.
Which One Should You Use?
In general, retinal is recommended over retinol — especially if treating acne is your key objective. But as with all skincare, it's better to go slow and steady before ramping up.
Already using retinoids and ready to upgrade? Maelove Moonlight Retinal Super Serum is formulated for those who have graduated past beginner retinol. New to the world of retinoids? Start with Maelove Stargaze Retinol Serum and work your way up.
For a comprehensive look at the full retinoid landscape, read Maelove's Deep Guide to Retinoids.
Written by our senior scientist Sunbin Song, PhD, and edited for clarity by Bradley Yim, our Head of Formulation. You can read more about them on our Team Page.
- Pechere M, Pechere JC, Siegenthaler G, Germanier L, Saurat JH (1999). "Antibacterial activity of retinaldehyde against Propionibacterium acnes." Dermatology. 199(suppl1): 29–31.
