The F.D.A. doesn’t require expiration dates on skin care. However, manufacturers voluntarily decide shelf life of their products. This can vary widely depending on the product and its active ingredients. Generally 18 to 24 months is the average. Most manufacturers don’t label their products with an expiration date. The exception to this is sunscreen.

Sunscreen is labeled as expiring three years after the manufacture date. Most skin care professionals would recommend throwing out sunscreen after one season. It is not worth the risk of a bad burn to save old sunscreen. Vitamin C is another product that can turn quickly. Vitamin C serum should be a light, golden color. If your Vitamin C is a dark gold or brown color, it should be thrown away.

Expiration dates can be tricky. A product may last longer than the expiration date or it may lose effectiveness long before the date. The factors that influence shelf life include exposure to high temperatures, exposure to sunlight, handling of product, and how long the package has been opened.

If you’ve had a product for over two years or there is a change in color or odor, the best rule of thumb is to start fresh with a new bottle.