Skincare Expiration Calculator

Why Skincare Expiration Matters

Skincare products are not immortal. Once opened, they are exposed to air, light, and bacteria, which can degrade active ingredients and compromise safety. Using expired products can lead to:

• Reduced Effectiveness: Active ingredients like Vitamin C and Retinol are unstable and lose potency over time.
• Skin Irritation: Degraded formulas can change pH levels or chemical structure, causing redness or breakouts.
• Infection Risk: Preservatives break down, allowing bacteria and mold to grow, especially in products you touch with your fingers.

Ingredient Spotlight: What Expires Fastest?

Not all products age the same way. Here is a breakdown of common ingredients and their stability:

• Vitamin C (L-Ascorbic Acid): Highly unstable. It oxidizes quickly when exposed to air, turning orange or brown. typically lasts 3-6 months after opening.
• Retinol & Retinoids: Sensitive to light and air. Packaging plays a huge role (airless pumps are best). Usually good for 6-12 months.
• Acids (AHA/BHA): Generally more stable due to lower pH, but can still degrade. Good for 12 months.
• Sunscreen: The FDA requires expiration dates on sunscreens. If yours doesn't have one, assume 3 years if unopened, but only 1 year after opening. Degraded sunscreen offers unreliable protection.

How to Find the "PAO" Symbol

Look for the Period After Opening (PAO) symbol on your product packaging. It looks like a small open jar with a number and the letter "M" inside (e.g., 6M, 12M). This tells you exactly how many months the product is safe to use after you break the seal.

Tips for Extending Shelf Life

• Store Cool and Dark: Heat and sunlight accelerate degradation. Keep products away from windows and steamy showers.
• Use a Spatula: Avoid dipping fingers into jars to prevent bacterial contamination.
• Tighten Caps: Ensure lids are screwed on tight immediately after use to minimize air exposure.
• Refrigerate (Selectively): Some products, like Vitamin C serums or sheet masks, can benefit from the fridge. However, check the label first—oil-based products may solidify or separate.

How to Use This Calculator

1. Select a Preset: Choose a product type to auto-fill the typical shelf life.
2. Enter Date Opened: Input the day you opened the bottle.
3. Check the PAO: If your product says "6M" but the preset says "12", adjust the "Shelf Life" field to match your package.
4. Add Notes: Type the product name to keep track of specific items.
5. Calculate & Copy: Get the expiration date and copy it to your calendar or notes app.