Methodology and editorial principles

What Evigrade publishes

Everything on Evigrade is an editorial review based on international guidelines, randomized controlled trials and meta-analyses.

How tiers are assigned

Tiers A–F follow a published editorial standard. AI agents apply it to official sources, and batch audits check the results. Ratings change when new studies appear.

For drugs, the tier rates one drug for one specific indication:

• Tier A – first- or second-line option in at least two international guidelines, backed by a systematic review, a meta-analysis or several good-quality RCTs
• Tier B – named in at least one international guideline, but not as the first choice: an alternative when first-line treatment does not suit, an option for a specific group of patients, or an add-on to non-drug treatment
• Tier C – sources of comparable quality disagree: trials or reviews reach conflicting results
• Tier D – benefit not proven: the data do not support an effect, the drug is missing from guidelines, or it has not been studied. No documented harm
• Tier F – documented harm: the drug is dangerous for this use, contraindicated, or its harm outweighs the benefit. Based on the label, halted trials, case reports or regulator warnings

For cosmetic ingredients, the tier rates one claimed action for one route of application. This scale is softer: two independent RCTs are enough for tier A, and guidelines are not required:

• Tier A – proven efficacy. Two or more independent RCTs with instrumental endpoints
• Tier B – limited evidence. One RCT or several controlled studies with limitations
• Tier C – weak evidence. In vitro data, open-label studies, or expert consensus
• Tier D – no data, or very weak or conflicting data
• Tier F – documented harm for this route of administration

The methodology follows the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation) and the Oxford Centre for Evidence-Based Medicine Levels of Evidence.

What we stand behind

All ratings on the site are editorial opinions, not statements of fact. We do not promote or disparage specific manufacturers: ratings refer to the international nonproprietary name of the drug, not to a brand.

Evaluative opinions based on public sources are not subject to factual refutation. The evidence rating is an editorial opinion grounded in publicly available guidelines and studies; it does not contain statements of fact susceptible to verification.

Right of reply

Manufacturers and rights holders may submit a reasoned reply to [email protected]. We publish the reply unedited within 14 business days.

A reply must include references to published scientific data. We may add our own commentary without changing the text of the reply.

Corrections and re-evaluation

We re-evaluate tiers as new randomized controlled trials, meta-analyses or updated clinical guidelines from international specialist associations appear. Drug, interaction and calculator pages show the date of their last update.

What the tier rates

Ratings apply to the international nonproprietary drug name and a specific indication, not to brands. The same INN receives different tiers for different indications. A tier F for one indication does not imply inefficacy for other indications.

Conflicts of interest

Evigrade is an independent encyclopedia with no direct commercial ties to drug or cosmetics manufacturers. Tier ratings do not depend on marketplace availability, manufacturer advertising budgets, or partnership requests.

Medical disclaimer

This content does not replace consultation with a licensed physician.

About the author

Editorial contact

General inquiries: [email protected]