Written by Gabrielle, Founder of iyvos and a clinician with ten years of hands-on clinical experience. Last updated: August 2026.
Quick answer: Skincare dupes rarely work the same as the product they copy, even with an identical ingredient list. An ingredient list (INCI) tells you what is in a product, not how much or how — and concentration, pH, delivery system, and stability decide the result. Two products can share every ingredient name and still behave completely differently on skin.
There's a video I get sent almost every week. Someone holds up two bottles — one expensive, one that costs the price of a coffee — flips them to the back, and reads the ingredient lists aloud. They're nearly identical. "Same ingredients," they say. "Save your money."
I understand why it's convincing. I spent ten years in clinic before I made anything of my own, and for a long time I believed a version of it too. But after two years reformulating iyvos from the ground up in Korea, I can tell you plainly: an identical ingredient list is one of the least reliable ways to judge whether two products will do the same thing to your skin.
Here's what the label doesn't tell you.
Do skincare dupes really work?
Sometimes a cheaper product genuinely is excellent. But "it has the same ingredients" is not the reason — and it's not proof of anything. A dupe copies the cast list. It rarely copies the concentration, the pH, the delivery system, or the stability engineering that decide whether those ingredients actually do their job. Same names on the label, different product on your face.
What is an ingredient list (INCI)?
An INCI (International Nomenclature of Cosmetic Ingredients) list is the row of standardised ingredient names on the back of every product. It is a list of what is in a formula. It is not a list of how much of each ingredient is present, and it says almost nothing about how those ingredients are prepared, combined, or delivered.
Think of the list as a cast of characters. It is not the script, the direction, or the performance.
What the label legally can (and can't) tell you
Ingredient lists follow real rules, and it helps to know exactly where those rules stop.
Ingredients are listed in order of concentration, from most to least — but only down to 1%. Below that 1% threshold, a brand can list ingredients in any order it likes (US FDA cosmetic labeling regulation 21 CFR 701.3; EU Regulation (EC) No 1223/2009). That matters, because many of the actives people care about most — retinoids, certain peptides, standardised extracts — are used below 1%. So two products can list the same active in what looks like the same position, while one contains a meaningful, studied concentration and the other contains a trace that's essentially there for the label.
The list also can't tell you the grade or purity of an ingredient, the form it's in, or how it was handled during manufacturing. "Vitamin C" on a label could be a stable, well-buffered derivative — or a raw form that oxidised months ago and is now doing very little.
The label is honest about what's present. It is silent about almost everything that determines whether it works.
Dupe vs formulation: what the label shows vs what it hides
Four things that change a formula with an identical INCI
When two products share a list but not a result, the difference is almost always hiding in one of these:
1. Concentration. The single biggest one. An active at a clinically studied percentage and the same active at a fraction of it are not the same product — and, as above, the list won't show you the difference once you're under 1%. Percentage is the whole game, and it's the number brands are least required to reveal.
2. pH. Many actives only work inside a narrow pH window, and some are irritating outside it. Pure vitamin C (L-ascorbic acid), for example, is only reliably absorbed into skin at a pH below 3.5 (Pinnell et al., Dermatologic Surgery, 2001). The same ingredient at the wrong pH can be useless, unstable, or harsh — and pH appears nowhere on an ingredient list.
3. Delivery system. Getting an ingredient onto skin is easy. Getting it to the right depth, at the right pace, without irritation, is the hard part — and it's done with encapsulation, emulsions, and carrier systems the INCI barely hints at. The same molecule delivered two different ways can behave like two different ingredients.
4. Stability and the "inactive" ingredients. The parts of a formula people dismiss as filler — the buffers, the emulsifiers, the antioxidants that stop the actives degrading — are the formulation. They decide whether the product still works in month six or quietly died in month two. Nobody dupes the boring, invisible engineering. It's the part that takes the longest to get right.
How to actually judge a skincare product
If the ingredient list isn't the answer, here's what to look at instead:
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Does the brand tell you the concentration of its key actives? A brand willing to name percentages usually has nothing to hide about them.
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Is there evidence behind the formula — testing, trials, a clear rationale — rather than a trendy ingredient name on the front?
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Does the formula make sense as a whole? Thoughtful products are built around how ingredients behave together: what supports what, what shouldn't be near what. A dupe copies the parts, not the reasoning.
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How does your skin respond over weeks, not minutes? The real test is never the swatch — it's your barrier a month later.
None of that fits in a fifteen-second side-by-side. Which is rather the point.
Why we spent two years reformulating in Korea
I'll be honest about our own bias here, because it's the whole reason iyvos exists in the form it does.
We already had a product. We could have kept selling it. Instead, in 2024, we moved our manufacturing from Australia to Korea and spent the next two years reformulating from scratch — not because the old formula was broken, but because I'd spent a decade watching skin and I knew it could be better. Korea is where the science is patient and the standards are relentless. We tore up formulas at 95%, because 95% isn't the point.
That's two years of decisions that will never show up on our ingredient list: the concentrations we landed on, the pH we held the line at, the delivery systems we chose, the stability testing that made the boring parts bulletproof.
You can dupe a bottle. You can dupe a shade, a scent, a label. What you cannot dupe is the two years of refusing to settle that sits behind it.
Made slow. Made in Korea. Made for years.
Frequently asked questions
Do skincare dupes really work? Sometimes a cheaper product is genuinely good, but a matching ingredient list is not the reason. Dupes copy the ingredient names, not the concentration, pH, delivery system, or stability that determine whether a formula actually works on skin.
Are two products with the same ingredients the same? No. An ingredient list shows what is in a product, not how much or in what form. Two products with identical ingredient lists can differ in active concentration, pH, delivery system, and stability — so they can behave completely differently.
Does the order of ingredients on a label matter? Only partly. Ingredients above 1% must be listed from most to least. Below 1% — where many key actives sit — a brand can list them in any order, so position near the end of a list tells you very little about how much is actually there.
Why do the same ingredients give different results? Because concentration, pH, delivery system, and formulation stability all change the outcome, and none of them appear on the ingredient list. The "inactive" buffers and emulsifiers that hold a formula together are a large part of why it works.
How can you tell if a skincare product is well formulated? Look for named active concentrations, evidence or testing behind the formula, a combination of ingredients that makes sense together, and — most importantly — how your own skin responds over several weeks rather than on first application.
About the author
Gabrielle is the founder of iyvos, a clinician-founded, Australian skincare brand manufactured in Korea. She spent ten years in clinical practice before founding iyvos and led the brand's two-year reformulation in Korea (2024–2026). iyvos formulates on the principle of made slow, made in Korea, made for years.
Sources
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U.S. Food & Drug Administration — Cosmetic labeling regulations, 21 CFR 701.3 (ingredient declaration order; the 1% threshold).
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European Union — Regulation (EC) No 1223/2009 on cosmetic products (labeling and ingredient order requirements).
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Pinnell SR, Yang H, Omar M, et al. "Topical L-ascorbic acid: percutaneous absorption studies." Dermatologic Surgery. 2001;27(2):137–142 (vitamin C absorption below pH 3.5).
Want the version of this story I don't write down — the footage, the doubts, the wins from those two years in Korea? It's all in Behind the Barrier, my Instagram channel. And if you buy once and buy right, the Skincare Society is where the people who think like this hang out.
