In Colin’s post on nail polish, he reminded me of a common question I’m asked about beauty products and cosmetics is “how long do they last?”. Most people are hesitant to throw out any product they haven’t finished so they typically have a bathroom cabinet filled with old cosmetics. Even I have some skin lotions that are at least 5 years old.
As a cosmetic formulator, you should have a good idea of how long these things last. Here is an estimation of types of products and how long they last.
Two years or more
When you are formulating, your goal should be to create a product that will pass stability testing for at least a year. So, products that last longer than this are going to be robust formulas that are not exposed to temperature extremes or intense lighting. The most stable formulations will be the ones that have ingredients that are all compatible, don’t evaporate, and are stored in light-proof bottles. They will most likely be anhydrous, or solutions (rather than emulsions) and have air-tight containers which don’t allow for significant weight loss. Some of the best candidates for products that will last this long include.
Clear Body Washes
Fragrances (in dark bottles)
Aerosols (hair spray, shaving cream, AP/Deo)
Powder color cosmetics
Lipstick / lip balm
One year to two years
When you start creating emulsions you reduce the stability of the products and they don’t last as long. But every well-formulated cosmetic should last at least a year. Here is a list of formulations that fall into this category.
Pearlized shampoos / body washes
Skin lotions / moisturizers
Liquid foundation / eyeliner / blush
Clear bottle products
Less than a year
There are a number of cosmetic products that are reactive and have a limited shelf life or they are not formulated to last. Here are some of the shortest lasting cosmetic formulas.
Products without preservatives
Products with high fragrance levels
Opened products that aren’t sealed properly
Warning signs: Products that are no longer good to use will typically start to smell funny, change color, taste different or feel different. But unless they are contaminated with microbes they should still be functional. This post about 5 ways beauty products go bad elaborates more.