METHODOLOGY
A source behind every detail.
How product facts, retailer ranks and price observations are collected and checked.
Updated 2026-10-08
Global research signals
The Global 40 starts with supplied research that references TikTok, Amazon US, Sephora, YesStyle Awards, Stylevana and overseas community discussion. It is not an independently measured sales ranking. A source-linked label means the supplied research named a source; a signal-led label means it needs direct evidence. Every exact product pack, regional availability, formula, price and popularity statement needs a product-level source check before publication as a product fact.
What the rankings mean
Earlier Korean retailer observations remain private supporting research. They are not the current coverage model and are excluded from the public sitemap. Observation dates use Korea Standard Time; exact collection times are not asserted when only the date has been retained.
Selection and original positions
The current Global 40 is organised by reported Amazon US, Sephora, YesStyle and TikTok signals. Its order comes from supplied research, not a combined rank calculation. We do not infer sales volume or current retailer rank. The earlier Korean lists remain archival context and do not determine global coverage.
Product identity and formulas
A common product ID connects its language versions. Packs, sets, sizes, colours and reformulations are tracked separately. A full formula must be tied to its exact version. Missing information stays unconfirmed and is not converted into a filter, badge or efficacy claim.
Price observations
Amazon US in USD is the global edition’s price basis. A price is recorded only with an exact pack description, seller, conditions and check date. A starting price is explicitly marked From and is not treated as a selected-option quote. Confirm the current USD price with Amazon US. No currency conversion or lowest-price comparison is provided.
Weekly workflow and corrections
Our cadence is Monday collection in Korea, an editorial draft, operator verification and a manual publication decision. There is no automatic publication. If collection fails, the previous data and its actual observation date remain. Historical snapshots retain their source basis and are indexed only when they include sufficient original context.
Changes across observations
Rank movement is calculated only when retailer, category and aggregation method match. The first observation has no comparison baseline. Source checks, observations, first publication, substantive edits and deployment are different dates.