Retinal sits one conversion step closer to active vitamin A than retinol. Here is what that means, and how to read Korean retinal labels from Beauty of Joseon, K-SECRET, and Dr.Different without misreading the percentage.
Retinal, short for retinaldehyde, is a form of vitamin A that sits one step closer to retinoic acid, the form skin cells actually respond to, than retinol does. That single step explains why retinal is often described as faster-acting than retinol, why it can feel stronger on the skin, and why it is harder to keep stable in a bottle. It also explains a puzzle on the shelf, where Korean retinal products print very different numbers on the front. Reading those numbers correctly matters more than the size of any one of them.
What Is Retinal, and How Is It Different from Retinol?
Retinoid is the umbrella term for vitamin A and its relatives. Skin converts the over-the-counter forms through a short chain: retinyl esters become retinol, retinol becomes retinal, and retinal becomes retinoic acid, also known as tretinoin, the prescription form. Retinol needs two conversions to reach the active stage. Retinal needs one.
That gives retinal a head start. As natural precursors, retinal and retinol tend to be less irritating than retinoic acid itself, which is part of why both are sold without a prescription. Retinal is still a retinoid, however, and it can cause dryness, flaking, or stinging, particularly in the first few weeks. First-time users often begin with retinol or a low-strength retinal.
The other difference is stability. Retinal degrades readily in light and air, so formulas rely on encapsulation, protective packaging, and supporting lipids. Here product design starts to matter as much as the ingredient name.
How Korean Brands Are Formulating Retinal
Korean brands have taken two broad routes. Some pair retinal with ginseng, insam (인삼), a staple of traditional Korean botanicals. Others build stepped concentrations so users can move up gradually. The three examples below are not ranked; each shows a different way of formulating the same ingredient.
Beauty of Joseon: Ginseng and Retinal in an Eye Serum
Beauty of Joseon’s Revive Eye Serum: Ginseng + Retinal is designed for the under-eye area, though the brand says it can be used across the face. It combines retinal liposomes with ginseng root extract, which the brand positions as the hydrating partner, alongside niacinamide and ceramide NP. International listings have advertised 2% retinal liposome and 10% ginseng root extract, while the current U.S. ingredient list places ginseng further down and prints no percentages. Formulas and labels can differ by market and version, so the box in your hand is the one to read.
K-SECRET: Black Ginseng and a Retinal Liposome Serum
K-SECRET’s SEOUL 1988 Serum: Retinal Liposome 2% + Black Ginseng opens its ingredient list with ginseng root extract, marketed at 58%. Black ginseng, heuksam (흑삼), is ginseng that has been steamed and dried repeatedly, which darkens the root; on an ingredient list it still appears simply as Panax Ginseng Root Extract. Niacinamide, bakuchiol, a vitamin C derivative, and peptides round out the formula. The SEOUL 1988 range also includes a 1% retinal liposome cream and a 4% retinal liposome eye cream.
Dr.Different: Stepped Retinal Creams
Dr.Different takes a more clinical route with its VITALIFT-A creams. Instead of a liposome-complex figure, U.S. retailers list the retinal itself: 0.05% in VITALIFT-A, 0.1% in VITALIFT-A Forte, and 0.15% in VITALIFT-A Fortessimo, with a separate Eye & Neck formula for thinner skin. The supporting ingredients are squalane, shea butter, ceramide NP, and hyaluronic acid, and first-time users are directed to the lowest step.
Why the Percentage on the Front Doesn’t Tell the Whole Story
Set these products side by side and the numbers seem to say that a 2% serum is twenty times stronger than a 0.1% cream. In fact they measure different things. “Retinal liposome 2%” describes the share of an encapsulated ingredient complex in the formula: retinal plus the lipids, sterols, and carriers that surround it. The pure retinal inside that complex is a small fraction of the figure. Where a listing does print the retinal content separately, it can be strikingly low; one published ingredient list for the K-SECRET serum marks retinal at 200 ppm, or 0.02%. Dr.Different’s figures, by contrast, refer to retinal itself.
Neither number tells you which product will work better on your skin; that depends on the whole formula and your own tolerance. The numbers only tell you that “2%” and “0.1%” cannot be compared directly.
A liposome is a microscopic vesicle made from phospholipids, the family of fats found in cell membranes, used to hold an unstable ingredient and release it more gradually. A niosome is a similar vesicle built from non-ionic surfactants instead, generally simpler and cheaper to produce. Both are established formulation tools, but when a brand calls its own encapsulation “stabilized,” that describes its formula; it is not the result of an independent comparison.
All three ingredient lists also share supporting lipids such as cholesterol, rapeseed sterols, and hydrogenated lecithin. These are the building blocks of the encapsulation, listed as separate ingredients. Retinal itself sits near the end of each list, a sign of how small its share of the formula is.
How to Choose and Use a Retinal Product
Before buying, it helps to check the label for:
- Whether the percentage refers to retinal itself or to a “retinal liposome” or complex.
- Where retinal sits in the ingredient list, and whether a ppm or percentage figure is printed for it.
- The product type and intended area, since an eye serum, a face serum, and a night cream are built for different skin and textures.
- Packaging: opaque tubes and airless pumps protect a light-sensitive ingredient better than clear jars.
- The brand’s own directions and warnings, including notes for sensitive skin.
Introduce it slowly: in the evening, on clean, dry skin, two or three nights a week, increasing only if your skin stays comfortable. Some Korean brands recommend buffering, with a light moisturizer before the retinal and a richer one after. Avoid using it on the same night as AHA, BHA, or PHA exfoliants, and wear a broad-spectrum sunscreen every morning, because retinoids can leave skin more sensitive overall. If stinging, redness, or peeling persists, stop and consult a dermatologist. Retinoids, retinal included, should be avoided during pregnancy and while breastfeeding.
Retinal is one ingredient with one conversion step, but the products built around it are not interchangeable. A ginseng eye serum, a black ginseng serum, and a stepped night cream are different answers to the same formulation problem. Once you know what the number on the front is actually measuring, the label begins to read less like marketing and more like a recipe.
