A skincare tool built by
someone who got tired of
not knowing what's in the bottle.

Most skincare information
is written to sell you something.

If you've ever tried to figure out whether a product is actually any good, you know the problem. Brand marketing is optimised for clicks, not clarity. Most "reviews" are affiliate content. Even the genuinely well-intentioned influencer advice tends to be based on what worked for their skin, not on what the research says.

Skin Stacker started as a private research habit — reading clinical papers, tracking ingredient concentrations that actually have evidence behind them, noting which combinations conflict and which genuinely synergise — and grew into the site you're using now. It's the resource I couldn't find, built to the standards I wished existed.

Hi, I'm JoAnn.

I'm an independent skincare researcher. I'm not a dermatologist, aesthetician or cosmetic chemist — and I won't pretend otherwise anywhere on this site. What I am is someone who reads the underlying research, checks manufacturer disclosures against INCI data, and translates all of that into plain English so you can make informed decisions without needing a degree in dermatology.

Every ingredient in the database links back to peer-reviewed sources (PubMed, ResearchGate, NIH, AAD) so you can follow the evidence yourself. When the evidence is thin, I say so. When an ingredient only works at certain concentrations, that's flagged. When two actives shouldn't be layered, the tool catches it before your skin does.

How the research actually works.

Every ingredient entry, compatibility rule, and concentration recommendation on Skin Stacker is built from the same process: start with the primary literature, work outward to clinical consensus, and flag clearly where the evidence thins out.

In practice, this means each ingredient claim is traced to a peer-reviewed source before it appears in the database. Not a blog post citing a brand press release, not a forum consensus — the actual study, with its methodology, sample size, and outcome measures. Where a single study makes a dramatic claim that hasn't been replicated, that's noted. Where the evidence is genuinely strong — retinol's collagen-stimulating effects, vitamin C's photoprotective synergy with ferulic acid, niacinamide's melanin-transfer inhibition — it's presented with confidence.

The sources I work from most regularly: PubMed and MEDLINE for dermatological and cosmetic science literature; the American Academy of Dermatology's clinical guidelines; the EU's Scientific Committee on Consumer Safety (SCCS) opinions on cosmetic ingredient safety; the FDA's cosmetic ingredient review database; and the Linus Pauling Institute's micronutrient research for vitamin-related ingredients. For formulation chemistry, I cross-reference the EU CosIng database and the Personal Care Products Council's INCI dictionary.

When I write that niacinamide at 5% is comparable to 4% hydroquinone for some PIH types, there's a specific Hakozaki et al. randomised trial behind that statement. When I write that the CE Ferulic combination produces eightfold photoprotection, that's the Lin et al. study from the Journal of Investigative Dermatology. The claims are not decorative — they're the conclusions of the research, translated into plain English.

The resource I couldn't find.

My interest in skincare science started the same way most people's does: with a skin concern, a product that didn't work, and growing frustration that the information available was either superficial or inaccessible. The accessible content was mostly marketing. The rigorous content was locked behind paywalls or written for clinicians.

I started keeping my own notes — a private database of ingredients, their evidence-backed concentrations, their interactions, and the gaps between what brands claimed and what the research supported. Over time, those notes became a tool. The tool became this site.

Skin Stacker is not a dermatology practice and I am not a clinician. What I can offer is careful, independent research — the kind that treats the primary literature as the authority rather than brand marketing, influencer consensus, or conventional wisdom that hasn't been updated since the science moved on. The niacinamide-and-vitamin-C compatibility question is a good example: the "they cancel each other out" claim circulated for years, but the actual chemistry, done under actual cosmetic use conditions, shows it's a laboratory artefact not relevant to skincare. Skin Stacker exists to make that kind of distinction accessible without a chemistry degree.

Every tool, every glossary entry, every blog post is an attempt to answer the question I kept asking: what does the evidence actually say? Not what does the brand say. Not what worked for someone on a forum. What does the peer-reviewed research, read critically and translated honestly, say about this ingredient, this combination, this claim.

Editorial principles.

These are the standards I hold Skin Stacker to. They're here so you know what you're reading and why to trust it — or not.

Independent

No brand has ever paid to be featured, recommended, rated, or included on this site. There are no affiliate links. There are no ads. There is no paid "partner content". If a brand's product is flagged as fairy-dusted or conflicted, that's what the ingredient list shows.

Research-cited, not opinion-led

Ingredient effects, concentrations and interactions come from peer-reviewed research and industry-standard references. Every glossary entry links to its sources. Where consensus doesn't exist yet, I say that explicitly rather than pick a side.

Honest about uncertainty

Cosmetic science is messy. Formulas vary. Individual skin biology varies more. When a claim is contested, under-studied, or only true at certain concentrations, Skin Stacker flags it — even when that's less satisfying than a confident answer.

Privacy-first

There's no login. Your skin profile lives only in your browser's local storage, never on a server. Product scans are processed for analysis and not retained. Google Analytics runs for aggregate traffic only — no personal data is sold, shared or sent to third parties.

Built in the open

If you spot something wrong — a mis-classified ingredient, a missing research citation, an outdated recommendation — please flag it. This site gets better because readers push back.

A few honest limits.

A few specific things Skin Stacker does not do:

• It doesn't diagnose. The "Diagnose a Reaction" tool ranks likely causes from your inputs — it doesn't tell you what you have.
• It doesn't prescribe. Prescription-strength actives (tretinoin, hydroquinone, spironolactone) get educational information only.
• It doesn't replace a patch test. No ingredient analysis, however detailed, predicts whether your skin will react. Always patch test a new product before adding it to your routine.
• It doesn't guarantee ingredient data. AI-estimated ingredient lists are clearly labelled as such. Verified data comes from Open Beauty Facts, which is good but not infallible. When precision matters, check the brand's official website or the physical label.

Who this owes to.

The skincare research community is full of people working harder than their profile suggests — dermatologists, cosmetic chemists, academic researchers and independent writers who make the primary literature accessible. Skin Stacker stands on a lot of their shoulders. Where a specific source shaped a recommendation, it's linked from the relevant glossary or blog page. Where a broader resource has been consistently useful — PubMed, the American Academy of Dermatology, the Linus Pauling Institute — you'll find them in the site footer.