Your PAO Guide 2026
Wondering what 3M, 6M or 12M means on your The Ordinary products?
PAO stands for Period After Opening. It tells you how long your skincare product is safe to use once it has been opened.
Quick Answers
✅ 3M = Use within 3 months of opening
✅ 6M = Use within 6 months
✅ 12M = Use within 12 months
✅ Unopened The Ordinary products have a shelf life of up to 3 years.
💙 Deciem Chat Room Tip
One of the biggest mistakes I see is buying too many products at once. A simple routine of 3–5 products is easier to follow, helps you stay consistent and gives your skin the best chance of improving. 👉 Build Your Personalised The Ordinary Regimen
How Long does a bottle of The Ordinary Last After Opening?
Wondering how long The Ordinary products last after opening? You’re not alone. Every The Ordinary product has a PAO (Period After Opening) symbol, which tells you how long the product should be used after it has been opened. This is different from the product’s unopened shelf life.
In this The Ordinary PAO Guide, you’ll learn what the PAO symbol means, how to find it on your products, how long each product lasts after opening, and the best way to store your skincare so it stays effective for as long as possible.
Whether you’re using The Ordinary Retinol, Niacinamide, Hyaluronic Acid, Vitamin C or one of the facial oils, this guide will help you get the most from every bottle and avoid wasting products.
Your Quick 30-Second Guide To PAO
- You will see 3M, 6M or 12M on the box and bottle. This means that once opened, you can use your products within that number of months.
- Write the date you opened your products on your bottle.
- Retinol/Retinoids have a PAO of 3 months and should be kept in the fridge.
- Retinal has a PAO of 6 months (no need to be refrigerated).
- Oils & Vitamin Cs have a PAO of 6 months.
- Antioxidants 6 months.
- Acids between 6 months and 12 months.
- Peptides 12 months. Copper Peptides 6 months.
- Eye products 6 months.
- Cleansers & Haircare between 6 and 12 months.
- The Ordinary says the shelf life of products unopened is up to 3 years.
- NIOD says the shelf life for unopened products is 18 months to 2 years.
What is The Ordinary PAO?
PAO stands for “Period After Opening“. You will find this little symbol somewhere on your box and product with 3M, 6M, 9M, 12M etc. This means that once you have opened your product, it should be used within 3 months, 6 months or 12 months. It’s worth writing when you open it on the box or bottle. These periods will vary and some products will have expiry dates.
The Ordinary & NIOD Expiry Dates vs PAO (Period After Opening)
One of the most common questions I receive is “Do The Ordinary products expire?” The answer is yes, but it’s important to understand the difference between an expiry date and the PAO (Period After Opening) symbol.
Most The Ordinary and NIOD products display a PAO symbol (an open jar with a number such as 3M, 6M or 12M), which tells you how long the product should be used after it has been opened. However, a small number of products have a printed expiry date instead.
The Ordinary & NIOD Products with Expiry Dates
The following products are labelled with an expiry date rather than just a PAO:
- The Ordinary UV Filters Sunscreens
- The Ordinary 100% L-Ascorbic Acid Powder
- NIOD Copper Amino Isolate Lipid (CAIL)
The Ordinary & NIOD PAO Guide
Below you’ll find the PAO (Period After Opening) for many of the The Ordinary and NIOD products I currently own. Please remember that The Ordinary regularly updates its formulas and packaging, so the PAO shown on your bottle or box may differ depending on when you purchased your product.
For example, one of my older bottles of Ascorbyl Glucoside Solution 12% has a 12-month PAO, whereas newer bottles may display a different PAO. Always check the symbol on your own product, as this is the most up-to-date guidance., and it says 12M but my latest Ascorbyl Glucoside says 6M.
The Ordinary Peptides period after opening
| Multi-Peptide Serum + HA Matrixyl Argireline | 12 Months PAO |
| Multi-Peptide Eye Serum Multi-Peptide Serum + Copper Peptides | 6 Months PAO |
The Ordinary Acids – How long do these last once opened?
| Glycolic Acid AHA 30% Lactic Acid 10% Lactic Acid 5% Mandelic Acid Azelaic Acid Salicylic Acid 2% | 12 Months PAO |
| Salicylic Acid Anhydrous Salicylic Acid Masque | 6 Months PAO |
The Ordinary Oils & Hydrators PAO
| NMF + HA NMF + PhytoCeramides NMF + Beta Glucan Hyaluronic Acid Marine Hyaluronics Amino Acids | 12 Months PAO |
| Squalane Oil Rose Hip Seed Oil B Oil Argan Oil Marula Oil | 6 Months PAO |
The Ordinary Retinol, Retinoid & Retinal – How long do these last once opened?
These should be refrigerated, so think before you buy any of these! Will you go to the fridge, put the product on and then put it back in the fridge?
| Retinal 0.2% Emulsion | 6 Month PAO |
| Retinol 1% in Squalane Retinol 0.2% in Squalane Retinol 0.5% in Squalane Granactive Retinoid 2% Retinoid 5% in Squalane | 3 Months PAO |
The Ordinary More Molecules
| Aloe 2% + NAG 2% Niacinamide 10% Alpha Arbutin Caffeine Solution | 12 Months PAO |
| Niacinamide Powder | Expiry Date |
The Ordinary Antioxidants PAO – How long do The Ordinary Antioxidants keep after opening?
| EUK 134 Pycnogenol Resveratrol & Ferulic Acid | 6 Months PAO |
The Ordinary Vitamin C PAO – How long do The Ordinary Vitamin Cs keep once opened?
| Vitamin C 23% Ascorbyl Glucoside Ascorbyl Tetraisopalmitate Solution Ethylated Ascorbic Acid 15% Solution 100% L-Ascorbic Acid Powder | 6 Months PAO |
The Ordinary PAO Period After Opening
Cleansers, Hair Care & Primers
NIOD PAO Period After Opening
All NIOD products say 6M, so they should be used within 6 months of opening. I find some of the masques go a bit crusty once they pass the 6-month period.
| NIOD CAIL | Expiry Date |
| All Other NIOD products | 6 MONTHS PAO |
Community Poll: Do you follow The Ordinary PAO?
I asked the Deciem Chat Room community on Instagram whether they replace their skincare products within the recommended Period After Opening (PAO).
65% admitted they continue using products beyond the recommended PAO.
While many people do this without noticing any issues, it’s always best to follow The Ordinary’s guidance and replace products once they reach their recommended PAO, particularly products containing ingredients such as retinoids or vitamin C that can become less effective over time.
What Is the Shelf Life of Unopened The Ordinary & NIOD Products?
If you’re stocking up during a sale, you may be wondering how long unopened The Ordinary products last.
The good news is that unopened skincare has a much longer shelf life than opened products, provided it is stored correctly in a cool, dry place away from direct sunlight.
According to DECIEM:
- The Ordinary products have an unopened shelf life of up to 3 years.
- NIOD products have an unopened shelf life of 18–24 months, depending on the formulation.
Once you open a product, the Period After Opening (PAO) symbol replaces the unopened shelf life as your guide. Always check the PAO symbol on the bottle or packaging to see how long the product should be used after opening.
A Note About Copper Peptides
From my own experience and feedback from the Deciem Chat Room community, I recommend using Copper Peptideproducts sooner rather than later. While they have an unopened shelf life, they are more delicate than many other formulations. If stored for too long after purchase or opening, they can gradually change from their distinctive bright blue colour to a much darker shade, which may indicate the formula has degraded.
Some Tips – The Ordinary PAO
- Write the date you opened the product on the bottle or box.
- Don’t have too many products open at once.
- Retinol and retinoids must be kept in the fridge and have a PAO of 3 months. The new Retinal 0.2% in a pump doesn´t need to be kept in the fridge and has a 6-month period after opening.
- Wipe the neck of the bottles after using them. Some products, particularly the oils and the caffeine solution, can get quite gloopy.
- NIOD Masques – I would advise buying the smaller sizes to be sure you use them in time.
- Don´t stock up on Copper Peptide products just because they’re on sale! We have found they don´t stay the gorgeous blue if stored too long.
Don’t have too many products open at once
💙 Deciem Chat Room Tip: Resist the temptation to buy every product at once. A simple routine of 3–5 products is easier to stick to, saves money and helps ensure you finish each product within its recommended PAO.
How to know if a product has gone off?
Here are the main signs that The Ordinary or NIOD product may have gone bad:
👃 Change in Smell
If your product develops an unusual, sour or rancid smell, it’s best to stop using it.
🎨 Change in Colour
Some ingredients naturally darken over time, particularly Vitamin C products. A slight colour change can be normal, but if the product has become dark orange or brown, it may have oxidised and be less effective.
🧴 Change in Texture
Watch for changes such as:
- Separation that doesn’t mix back together.
- Clumping or graininess.
- Thickening or becoming unusually runny.
These changes may indicate the formula is no longer stable.
🔥 Skin Irritation
If a product you’ve previously used without any problems suddenly causes burning, stinging, redness or irritation, stop using it. Changes in the formula over time may make it unsuitable for your skin.
💙 When in Doubt, Replace It
If you’re unsure whether a product is still safe or effective, it’s usually better to replace it. Fresh skincare is more likely to deliver the results you’re expecting, especially with active ingredients such as Retinoids, Vitamin C and Copper Peptides.If in doubt, it’s better to replace it.
Remember: The PAO is a guide, not a countdown timer. Always use your eyes, nose and common sense alongside the manufacturer’s recommendations.
Will You Finish Your Bottle Before the PAO?
One of the biggest reasons people go beyond the recommended Period After Opening (PAO) is simply because they have too many products open at once.
But how long should a 30ml bottle actually last?
I’ve tested this by counting the number of drops in a bottle and worked out roughly how long popular The Ordinary serums last with everyday use.
👉 Read: How Long Does a Bottle of The Ordinary Last?
