How long before my moisturizer “goes bad”?

Unopened products can last three years. But once you open a bottle or jar of moisturizer and skin lotion, its ingredients (including sunscreen or Vitamin C) can deteriorate after 2 years. Since bacteria can hasten deterioration, jars where you dip you finger in lasts shorter than pumps and tubes. Heat can also speed up deterioration, so plastic packaging is better than glass packaging. To preserve ingredients, store them in a cool place.