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Methodology

How we evaluate evidence.

645 citations across 10 databases, each one a specific source you can check. We grade every study by what it actually found, then sort the evidence into tiers. Below is the framework, the source list, and the rules we follow.

What our citations show

376
Positive efficacy

Single trials or meta-analyses concluding the ingredient works clinically.

43
Safety / regulatory

Cosmetic Ingredient Review (CIR), Scientific Committee on Consumer Safety (SCCS), or Korean Ministry of Food and Drug Safety (MFDS) documents. Safe to use at typical concentrations.

206
Mechanism only

Shows how the ingredient works in lab tests (in vitro), not proof it works on real skin.

20
Mixed / inconclusive

Reviews that explicitly say "trials needed" or "benefit unclear". We list them honestly.

We cite specific papers for all 129 ingredients we track.

Excellent
15+ studies or large cohort

Multiple randomized controlled trials (RCTs), a systematic review, or a large longitudinal cohort. Mechanism confirmed at molecular level. Effect size meaningful at typical concentrations. (In-vitro / lab-only mechanism studies do not alone qualify an ingredient for the Excellent tier: human clinical data or regulatory approval is required.)

Good
5–14 studies

Several controlled trials, but smaller samples or mixed results. Mechanism plausible and partially confirmed.

Fair
No clinical proof yet

Used in tradition or reported anecdotally to help, but we don't yet have controlled clinical evidence. May work for some people; we track these as the research catches up.

Ingredient research is not a product trial

A study of an ingredient cannot establish that every product containing it will deliver the same result. Formula, concentration, delivery system, routine, and the study population all matter. When a retailer or brand discloses a concentration, we can show that label fact; it does not make the finished product clinically proven.

We reserve product-level efficacy language for an exact product study that we can link and describe. Otherwise, product pages label the research as ingredient-level and keep its limits near the retailer link.

Our 10 sources

We pull from databases that cover skincare research and regulators worldwide, well beyond Western dermatology. Each name links to the underlying database or regulator's own site (645 citations, primarily from PubMed (630) plus 9 additional regulatory and regional databases including KCI, Cochrane, and MFDS):

🌐
PubMed
US National Library of Medicine, the biomedical literature index
630
🌐
Cochrane
Independent systematic reviews of clinical evidence
6
🇰🇷
KCI
Korea’s national index of peer-reviewed academic journals
12
🇰🇷
KoreaMed
Korean medical journal aggregator that indexes Annals of Dermatology
5
🇯🇵
J-Stage
Japan’s national database of scientific & medical journals
4
🇨🇳
VIP
Chinese scientific journals with medical and dermatology coverage
3
🇫🇷
SFD
French dermatology society, publisher of Annales de Dermatologie et de Vénéréologie
4
🇰🇷
MFDS
Korean regulator that approves cosmetic functional actives
5
🇪🇺
SCCS
EU regulator’s cosmetic-safety panel, with opinions on actives + restrictions
6
🇺🇸
CIR
Independent US cosmetic-ingredient safety review panel
4

Counts grow as we add citations on a rolling basis. Every database listed here has at least one specific citation behind it; we do not count a source until it does. Chinese (Chongqing VIP) and French (SFD / Annales de Dermatologie) coverage is in active expansion for K-beauty botanicals and pigment-correction research.

How an ingredient gets in the database

  1. GlowPal's owner and contributors identify candidate ingredients from journal scans and reader requests.
  2. We collect the relevant citations we can source (human studies, laboratory work, animal research, reviews, and regulatory documents) and tag the study type and outcome.
  3. We aim for at least 3 sources across two or more databases before an ingredient is added. A small number of entries currently sit below that, and they are the ones carrying our lowest evidence tier: the tier chip on every ingredient is the honest signal, not this target.
  4. Tier considers study design, applicability, outcome, and consistency; a citation count alone does not establish efficacy.
  5. Claims about the catalog should link to a specific source. Product claims separately identify when the evidence is ingredient-level.

How tiers can change

We change a tier when new or reassessed sources materially change the quality, applicability, or consistency of the evidence. We do not use a fabricated review date or promise a fixed review schedule; substantive changes should be visible in the catalog and its linked sources.

What we don't do

  • We don't accept industry-funded studies as the sole source for a tier upgrade.
  • We don't cite blogs, Reddit threads, or product marketing pages.
  • We don't cite an LLM as a source. Ever.
  • We may earn a commission when you buy through a product link. Product candidates come from the retailer and affiliate feeds available to us, so the catalog is not an exhaustive or independent survey of the market. Full disclosure.