
UPDATED NOVEMBER 2020. The Ordinary Conflicts – so apart from all the confusing names and how to layer The Ordinary, you also need to understand about The Ordinary products that conflict. Some products conflict and some shouldn´t be used together as they may cause irritation.
The Ordinary Conflicts
NEW! Deciem has recently updated The Ordinary conflicts and there are quite a few changes. When Deciem has been questioned about this on Social Media they often say it’s for people new to skincare or with sensitive skin.
The main change is Niacinamide and Vitamin c derivatives. Before Deciem always said only direct/pure vitamin c conflicted, but now they say all vitamin cs including the derivatives. Please see their response below.
- This is the latest information by Deciem in their Knowvember The Ordinary Beginner´s Guide.
- Always read the instructions on the Deciem website before using a product.
- Patch testing is highly recommended.
- Please link to this page rather than screenshot as information is regularly updated.
- This is just a guide and this page takes no responsibility for any issues that may occur.
All The Ordinary Products

The Ordinary Products With No/Few Conflicts
Vitamin C Derivatives conflicts with Niacinamide (serum & powder)
More Molecules
Oils & Hydration
- B Oil
- Marula Oil
- Moroccan Argan Oil
- Rose Hip Seed Oil
- Chia Seed Oil
- Sea-Buckthorn Fruit Oil
- Hemi-Squalane
- Amino Acids
- Hyaluronic Acid
- Marine Hyaluronics
- Natural Moisturising Factors
Deciem Explains Why Certain The Ordinary Products Should Not Be Used Together
Vitamin C pure & derivatives & Niacinamide
We do not recommend combining Vitamin C (L-Ascorbic Acid, Ethylated L-Ascorbic Acid or Vitamin C Derivatives) with Niacinamide with Direct or Ethylated Vitamin C, and Vitamin C Derivatives due to the formation of a salt complex that has the potential to reduce the integrity of both compounds. If you wish to combine both products into a regimen, we recommend using them on alternate days and/or nights.
Why can´t you use The Ordinary Peptides & Acids in the same routine?
Our rule against combining strong antioxidants only applies to our products containing copper peptides. We would not recommend combining direct acids with peptides due to the susceptibility of peptides to hydrolysis (which breaks the bonds between peptides, reducing their efficacy, and making them into individual amino acids). At low pH, the peptides undergo processes such as deamidation (the removal of an amide group) and oxidation, which compromise the activity of the peptides.
Having said that, if you have previously combined peptides with acids and have not experienced any negative side effects or discoloration, you may continue to combine the two products as so as the combination does not pose any potential harm. Our recommendations are meant to serve as a preventative measure to avoid any incompatibility between those combinations and also because of skin tolerance in subjective.
Why can´t I mix The Ordinary Niacinamide with pure Vitamin C?
Deciem says: Our contraindication is specific to our products and their concentrations. If you’ve used them together in the past and the combination has worked for you without any issues, you may continue to do so.
You can find lots more Deciem FAQs here. Q&A found on Social media.
Other The Ordinary Conflicts & Conflicting Information
There’s a lot of conflicting information,particularly about Niacinamide and Vitamin C. Deciem suggest to avoid using their Vitamin C & Niacinamide in the same routine. Others say they are ok together. The more you read on the internet the more confusing it will be.
If you are an experienced skincare user then I’m sure you have done your homework and know what’s best for your skin. For those of you who are new to skincare, it´s really down to you to decide whose advice to take. Personally, if using Deciem products then I would take their advice, especially if you are new to skincare. Remember, they do recommend patch testing and it´s good practice to patch test when you introduce 2 products in case of irritation.
Deciem Regimen Page
You can find all the conflicts above on the Deciem Regimen page.
