5 products — the list includes an ingredient known to break down faster in heat — pure vitamin C, a retinoid, benzoyl peroxide or a protein enzyme.
How this list is made: we include a product when its published ingredient list matches the rule above. It says nothing about how well a product works or whether it suits your skin. Sorted by brand and name — no product pays to be here.
List rebuilt daily from our product records · 2026-10-17
5 products, picked because the list includes an ingredient known to break down faster in heat — pure vitamin C, a retinoid, benzoyl peroxide or a protein enzyme. The list is rebuilt every day from the published ingredient lists.
Only by what the brand's published ingredient list says. We do not test products, and the list is not a ranking — it is sorted by brand and name, and no product pays to be included.
No. It means the list includes an ingredient that breaks down faster in heat; how much depends on the amount, the packaging and the rest of the formula. Some products use vitamin C in tiny amounts, for example to adjust pH.
Keep them closed, out of direct sun and away from heat — not in a hot car or a sunny window. Korea requires every cosmetic label to carry storage directions; follow the label and the period-after-opening symbol.
Pure vitamin C often turns yellow or brown as it oxidizes, which also means it has lost strength. If color, smell or texture changes, stop using it and check with the brand.
We can't say. This is a records list, not advice. If you have a skin condition or allergies, ask a dermatologist or pharmacist.