1
Add products
Build your routine with at least two products from search or custom entries.
Use complete product names for better matching and fewer misses.
About Norethia
Check compatibility, understand why, and keep your routine organised.
Informed by ongoing cosmetic science study and a careful, ingredient-led approach.
How it works
2
Paste ingredients
Paste the full ingredient list to give the check more context.
This is especially useful when a product is not already listed.
3
Run the check
Norethia looks for known layering conflicts based on ingredients and any modes you switch on.
Results stay consistent, with clear, considered explanations.
4
Apply guidance
Read verdict, reasons, and suggested timing/frequency changes for the routine.
Use clinician guidance for medical concerns or when using prescription treatments.
FAQ
Is this medical advice?
No. For educational use only. Not medical advice. Always patch test before using new products.
Does Norethia diagnose skin conditions?
No. It highlights combination patterns only and does not diagnose or treat conditions.
Does it store my ingredient lists?
If you choose to save products, routines, or checks while signed in, that information can be stored to sync across app and web. See the Privacy Policy for details.
What does reactive-skin caution change?
It increases caution where stacked strong actives may raise irritation risk.
What if a product is missing from search?
Paste the full ingredient list and Norethia will review it directly.
Where do shared search results come from?
Open Beauty Facts data is kept separate from Norethia-reviewed product submissions. Some product data is sourced from Open Beauty Facts (openbeautyfacts.org), contributed by the Open Beauty Facts community under the Open Database License (ODbL).
What is the difference between CAUTION and AVOID?
CAUTION usually means adjust timing/frequency; AVOID is reserved for higher-risk contexts in common guidance.
Should I still patch test?
Yes. Always patch test new products and check the packaging, formulas can change, and a compatibility check is not a guarantee of safety for your skin.
How does the free trial work?
Eligible new subscribers receive full access to Norethia Premium for 7 days. The subscription then renews at the monthly price shown by Apple unless it is cancelled before the trial ends.
When does my trial begin?
Your trial begins when you confirm the Premium subscription through the App Store. It does not begin when you download Norethia or visit this website.
Can I cancel during the trial?
Yes. You can manage or cancel the subscription through your Apple account settings. Apple will show the applicable renewal date and price before you confirm.
Why can't I see the free trial?
Introductory trial eligibility is determined by Apple. People who have previously used an introductory offer within the same subscription group may not be eligible.