So apart from all the confusing names and layering, you also need to understand about The Ordinary product conflicts. I highly recommend you read through this page or the official Deciem Regimen Page so you understand which products can and can´t use together.

I have created a chart using the information given by Deciem on their regimen page. ONLY the products that have conflicts are mentioned here. If you use other brands, then you need to check their ingredients too.

On the official regimen page there are some conflicts that are missing from some of the products, but I think I have covered these in the charts below. If you spot any mistakes please let me know.

This chart is for guidance only. Always read instructions before using products and it is always recommended that you do a patch test.

Please link to this page, not just screenshot, because this page is regularly updated.

What if my Ordinary products conflict?

If you have been using conflicting products, don´t panic, just stop using them together from now on and alternate then morning and evening or use on different days.

The Ordinary Acids

I asked Deciem about their wording “Strong Acids” and “Direct Acids”. Their reply was that they mean the same. Direct Acids are; AHA 30%, Azelaic Acid, Glycolic Acid, Lactic Acid 5 & 10%, Mandelic Acid, Salicylic Acid and Alpha Lipoic.

The Ordinary Peptides

Peptides are Buffet, Buffet + Copper, Matrixyl and Argireline. Buffet + Copper Peptides has a few more conflicts than the others. Always read the instructions and double check with Deciem if you’re unsure.

The Ordinary Vitamin C Products

When Deciem say “do not use with pure vitamin c”, this applies to most of the vitamin c products; Vitamin C 23% & 30%, Ascorbic Acid 8% + Alpha Arbutin 2%, Ethylated Ascorbic Acid 15% Solution, 100% L-Ascorbic Acid Powder.

The only vitamin c products that are conflict free are the Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F, Ascorbyl Glucoside Solution 12% and Magnesium Ascorbyl Phosphate 10%. If you find all these conflicts confusing, I would personally advise to start with one of these.

Other Conflicts & Conflicting Information

If you follow Deciem on Instagram, they will often suggest using Retinoids / Retinols, Acids and Vitamin Cs in different regimens due to irritation. There’s also conflicting information about Niacinamide and Vitamin C. The more you read on the internet the more confusing it will be with conflicting advice, but it´s important to read and learn. If you are an experienced skincare user then I’m sure you have done your own 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 I’m using Deciem products then I will take their advice. Remember, they do recommend patch testing and it´s good practice to patch test when you use 2 products in case of irritation.

The Ordinary Products & Conflicts

Products	Conflicts
Retinoid 2%	other retinoid / retinol products
Retinoid 2% Squalane	other retinoid / retinol products
Retinoid 5% Squalane	other retinoid / retinol products
Retinol 0.2% Squalane	other retinoid / retinol products
Retinol 0.5% Squalane	other retinoid / retinol products
Retinol 1% Squalane	other retinoid / retinol products
Alpha Lipoic	Direct Acids EUK 134 0.1% (peptides) Buffet | Buffet + Copper Matrixyl | Argireline
EUK 134	Highly Acidic Formulations of Ascorbic acid; L´Ascorbic Acid | Ethylated Ascorbic Acid Buffet + Copper Peptides
Resveratrol & Ferulic Acid	Buffet + Copper Peptide
AHA 30%	Direct Acids | EUK 134 Peptides Buffet | Buffet + Copper Matrixyl | Argireline
Azelaic Acid	Direct Acids | EUK 134 Peptides | Buffet | Buffet + Copper Matrixyl | Argireline
Glycolic Acid	Direct Acids | EUK 134 Buffet | Buffet + Copper Matrixyl |Argireline
Lactic Acid 5%	Direct Acids | EUK 134 Buffet | Buffet + Copper Matrixyl | Argireline
Lactic Acid 10%	Direct Acids | EUK 134 Buffet | Buffet + Copper Matrixyl | Argireline
Salicylic Acid	Direct Acids | EUK 134 Buffet | Buffet + Copper Matrixyl | Argireline
Salicylic Acid Masque	Direct Acids | EUK 134 Buffet | Buffet + Copper Matrixyl | Argireline
Mandelic Acid	Direct Acids | EUK 134 Buffet | Buffet + Copper Matrixyl | Argireline
L ´Ascorbic Acid Powder	Niacinamide | EUK 134 Buffet | Buffet + Copper, Matrixyl |Argireline | The Acids |
Vitamin C Suspension 23%	Niacinamide | EUK 134 | Buffet | Buffet + Copper | Matrixyl | Argireline
Vitamin C Suspension 30%	Niacinamide | EUK 134 | Buffet | Buffet + Copper | Matrixyl | Argireline
Ethylated Ascorbic Acid	Niacinamide | EUK 134 Buffet | Buffet + Copper Argireline |Matrixyl
Ascorbic Acid + Alpha Arbutin	Niacinamide + EUK 134 | Buffet | Buffet + Copper | Matrixyl | Argireline
Niacinamide	Pure Vit C, Ethylated Ascorbic Acid, L´Ascorbic Acid Powder | Vit C 23% & 30% | ELAA Ethylated Ascorbic Acid | Ascorbic Acid + Alpha Arbutin (there is conflicting information about using Niacinamide and Vit C, so please do your own research)
Buffet	Direct Acids | Pure Vit C products including L ´Ascorbic Acid & Ethylated Ascorbic Acid | Vitamin C 23% & 30% | Ascorbic Acid + Alpha Arbutin
Buffet + Copper	Direct Acids | Pure Vit C products including L´Ascorbic Acid | Ethylated Ascorbic Acid |Vitamin C 23% & 30% | Ascorbic Acid + Alpha Arbutin EUK 134 | Alpha Lipoic Acid | Resveratrol + Ferulic Acid
Argireline	Direct Acids | Pure Vit C proucts including L ´Ascorbic Acid | Vitamin C 23% & 30% | Ascorbic Acid + Alpha Arbutin | Ethylated Ascorbic Acid
Matrixyl	Direct Acids | Pure Vit C products including L ´Ascorbic Acid | Ethylated Ascorbic Acid | Vitamin C 23% & 30% | Ascorbic Acid + Alpha Arbutin