To a skin-care junkie, there are few things more satisfying than opening up your bathroom mirror to find an expertly curated collection of products. But as the weeks and months go by, and bottles of serums and creams go unused (or sit in their jars only half-finished), there’s a good chance those active ingredients are slowly losing their efficacy. Worse yet, they might lead to serious skin problems, like an infection, if you don’t dispose of them at the correct time. All the more motivation to stick to a consistent skin-care routine, right? Right!
There’s a lot of intel to collect about what ingredients break down the fastest, as well as the best methods for prolonging a product’s shelf life, so we turned to Michelle Wong, aka labmuffin, a Sydney-based science educator who is using her PhD in chemistry to teach her fellow beauty lovers about makeup and skin care. With her refreshing mix of transparency, skepticism, and a true passion for the industry, she gave us a thorough rundown of our favorite products, how long they last, and how we can keep ourselves healthy and safe. Check out her advice below.
There’s a lot of intel to collect about what ingredients break down the fastest, as well as the best methods for prolonging a product’s shelf life, so we turned to Michelle Wong, aka labmuffin, a Sydney-based science educator who is using her PhD in chemistry to teach her fellow beauty lovers about makeup and skin care. With her refreshing mix of transparency, skepticism, and a true passion for the industry, she gave us a thorough rundown of our favorite products, how long they last, and how we can keep ourselves healthy and safe. Check out her advice below.
What are the dangers of using a product past its expiration date?
For as much as you want to prolong a product’s shelf life (we get it, you invested hard-earned dollars into that new face cream), there is a very real possibility that it can cause problems for your skin. Says Wong, “If a product is past its expiration date, there’s a higher possibility of it going off. This can range from the product’s texture going strange, to actives and sunscreen chemicals no longer working, to oils going rancid, to having too many microbes in the product, which can lead to an infection.” In other words, you can’t ignore a product’s expiration date no matter how steep a product’s price tag. Do it for your skin’s health.
What determines a product’s shelf life?
It varies depending on the formulation. “Shelf life depends on a lot of things, including the active ingredients in the product, the preservative system, the packaging, the storage conditions (especially temperature), how frequently the product is opened, and the overall formula.” Wong also explains that the expiration date is an estimate and can change depending on the storage conditions. “A sunscreen kept in the glove box of a car in summer will have a much shorter shelf life than one that’s kept in a cool dark place, for example.” When in doubt, keep your products indoors and out of the heat.
What types of products expire the fastest?
“Generally, unpreserved products will expire the fastest, especially if they contain water.” Check the packaging for more insight on a product’s formulation (and remember, water will show up as “aqua” for most items).
For as much as you want to prolong a product’s shelf life (we get it, you invested hard-earned dollars into that new face cream), there is a very real possibility that it can cause problems for your skin. Says Wong, “If a product is past its expiration date, there’s a higher possibility of it going off. This can range from the product’s texture going strange, to actives and sunscreen chemicals no longer working, to oils going rancid, to having too many microbes in the product, which can lead to an infection.” In other words, you can’t ignore a product’s expiration date no matter how steep a product’s price tag. Do it for your skin’s health.
What determines a product’s shelf life?
It varies depending on the formulation. “Shelf life depends on a lot of things, including the active ingredients in the product, the preservative system, the packaging, the storage conditions (especially temperature), how frequently the product is opened, and the overall formula.” Wong also explains that the expiration date is an estimate and can change depending on the storage conditions. “A sunscreen kept in the glove box of a car in summer will have a much shorter shelf life than one that’s kept in a cool dark place, for example.” When in doubt, keep your products indoors and out of the heat.
What types of products expire the fastest?
“Generally, unpreserved products will expire the fastest, especially if they contain water.” Check the packaging for more insight on a product’s formulation (and remember, water will show up as “aqua” for most items).
What active ingredients break down the fastest?
Although it’s one of our favorite ingredients for fading dark spots and evening out the complexion, vitamin C is typically the first to go. “L-Ascorbic acid in unstabilized water-based formulas breaks down very quickly.” Unless it’s an extremely high concentration, you can use a vitamin C every day (once a day), but always build up the application to see what agrees with your skin. Vitamin C will turn an orange or deep yellow once it starts to break down, so be sure to pay attention to the liquid itself the longer you keep it on your shelf.
What is the average shelf life for a topical vitamin C serum?
There is a lot of variation depending on the formula, but Wong says it can be a few weeks to a few years. An oil-based formula is your best bet if you’re not using it daily.
What about the shelf life for other popular skin-care and makeup products like hyaluronic acid? Retinol? Mascara? Sunscreen?
“Hyaluronic acid, if adequately preserved, [can last] up to a year. Retinol, around six months. Mascara, around three months. Sunscreen [is about] two to three years.”
What can you do to prolong a product’s shelf life, if possible?
“Store it in a cool, dry, dark place, [and] minimize exposure to humidity (e.g., don’t open it in a damp bathroom after a shower). Use jar products with clean hands.” That means that although it might be visually appealing to arrange your most beautifully packaged products by your window or on a vanity, it’s always wiser to store them away from the light.
Although it’s one of our favorite ingredients for fading dark spots and evening out the complexion, vitamin C is typically the first to go. “L-Ascorbic acid in unstabilized water-based formulas breaks down very quickly.” Unless it’s an extremely high concentration, you can use a vitamin C every day (once a day), but always build up the application to see what agrees with your skin. Vitamin C will turn an orange or deep yellow once it starts to break down, so be sure to pay attention to the liquid itself the longer you keep it on your shelf.
What is the average shelf life for a topical vitamin C serum?
There is a lot of variation depending on the formula, but Wong says it can be a few weeks to a few years. An oil-based formula is your best bet if you’re not using it daily.
What about the shelf life for other popular skin-care and makeup products like hyaluronic acid? Retinol? Mascara? Sunscreen?
“Hyaluronic acid, if adequately preserved, [can last] up to a year. Retinol, around six months. Mascara, around three months. Sunscreen [is about] two to three years.”
What can you do to prolong a product’s shelf life, if possible?
“Store it in a cool, dry, dark place, [and] minimize exposure to humidity (e.g., don’t open it in a damp bathroom after a shower). Use jar products with clean hands.” That means that although it might be visually appealing to arrange your most beautifully packaged products by your window or on a vanity, it’s always wiser to store them away from the light.
For makeup products, does a powder or cream formula tend to last longer than the other?
We’re always oscillating back and forth between a cream or powder blush, highlighter, and eyeshadow, but Wong says a powder formula might be the way to go if you want your products to hold up. “Water-free formulas tend to have longer shelf lives, much like how dry food lasts longer than wet food, so powders tend to last a lot longer. Having the right preservatives at a high enough concentration is also important. For example, the preservation system needs to protect both the oil and water parts of an emulsion, and it needs to be compatible with the pH of the product. Using more saturated oils and antioxidants in the formula also helps.”
How does a product’s packaging help prolong or speed up shelf life?
While we love a pretty jar, there’s no denying that a pump top (or other air-tight systems) will keep your product stable longer. “Air-free packaging stops contamination, oxygen, and water from entering a product, so that tends to prolong shelf life. The material used for the packaging also needs to be compatible with the formula for a long period of time. Dark packaging that excludes light also stops light from breaking down the product.” For vitamin C especially, be on the lookout for dark, opaque packaging.
Are there any products or ingredients that don’t expire?
“There are a few—dry powders, for example, tend not to expire (e.g., pure iron oxide). The texture may still change, though! The vast majority of consumer products will expire.” Accept the things you cannot change, folks.
Do you find that the products’ recommended expiration time is usually correct on average?
Always err on the side of caution, says Wong. “Recommended expiration times are usually very conservative, to take into account the fact that the product won’t usually be stored under ideal conditions, and to reduce the risk of harm.”
Want more stories like this?
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We’re always oscillating back and forth between a cream or powder blush, highlighter, and eyeshadow, but Wong says a powder formula might be the way to go if you want your products to hold up. “Water-free formulas tend to have longer shelf lives, much like how dry food lasts longer than wet food, so powders tend to last a lot longer. Having the right preservatives at a high enough concentration is also important. For example, the preservation system needs to protect both the oil and water parts of an emulsion, and it needs to be compatible with the pH of the product. Using more saturated oils and antioxidants in the formula also helps.”
How does a product’s packaging help prolong or speed up shelf life?
While we love a pretty jar, there’s no denying that a pump top (or other air-tight systems) will keep your product stable longer. “Air-free packaging stops contamination, oxygen, and water from entering a product, so that tends to prolong shelf life. The material used for the packaging also needs to be compatible with the formula for a long period of time. Dark packaging that excludes light also stops light from breaking down the product.” For vitamin C especially, be on the lookout for dark, opaque packaging.
Are there any products or ingredients that don’t expire?
“There are a few—dry powders, for example, tend not to expire (e.g., pure iron oxide). The texture may still change, though! The vast majority of consumer products will expire.” Accept the things you cannot change, folks.
Do you find that the products’ recommended expiration time is usually correct on average?
Always err on the side of caution, says Wong. “Recommended expiration times are usually very conservative, to take into account the fact that the product won’t usually be stored under ideal conditions, and to reduce the risk of harm.”
Want more stories like this?
The 411 on Skin-Care’s 5 Most Popular Ingredients
7 Products for an Effortless Summer Makeup Look
The Best Serums to Fade Dark Spots