Take a look at the bottom of your tube of mascara. Actually, this goes for all kinds of cosmetics (face creams, eye shadow, foundations, etc.) There should be a picture of an open jar that has either 3M, 6M, 12M, 18M on it. That is how long your cosmetics can be used after you open it, essentially an expiry date (yes, cosmetics indeed DO expire!).
image care of bunbunmakeuptips.com
For mascara and most eyeliners/eye primers, the is anywhere between 3-6 months. For eyeliner pencils that need to be sharpened, that's around 36M. As a former microbiologist, I STRONGLY recommend that you follow the manufacturer's suggestion. Have you ever heard of the "mini world inside your eyelashes"? That because it actually exists. Your eyelashes help protect your eyes from daily assaults, not only from things like blazing sunshine, but from all of the crap in the air that you and I breathe in. Our nostrils have nose hairs, our respiratory tract has cilia, and our eyes have eyelashes. Anything that our eyelashes don't catch is caught in our tears and eventually "cried out".
I'll be the first to admit it - for a while I kept mascara for as long as there was still product in the tube. After studying some microbiology in school and working for a while in the cosmetics industry, I realized how nasty that was. Every time your mascara wand applies product to your lashes, it combs your lashes of all the crap they caught protecting your eyes. So for as long as you're using that same mascara tube, you're dragging more and more crap through your eyelashes. Bacteria is multiplying at exponential rates - the bacteria already in your tube from past uses, and the bacteria you're going to collect on it the next time your use it on your lashes, will be multiplying at astronomical rates.
This is precisely why I think that mascara tip (adding contact lens solution to your dried up mascara tubes) on Pinterest is absolutely revolting. Yuck.
The 3-6 month expiry also considers the mascara's consistency. Every time you open up your mascara, you're pumping more air into it, drying it out. Your mascara will keep the same, usable consistency for about 3-6 month's time. After that, the formula has been exposed to waaay too much air and is no longer suitable to use.
So what do to? First, throw away all of the mascara you purchased and opened before the end of last year. A makeup artist friend of mine writes the dates she opens up her mascara on the actual tube to help her remember. As per my last post, I like to use the small tubes you get in GWPs or as samples because there's only enough product in there to last you a few months evenwith every day use, so you don't have to worry about exceeding your mascara's expiry date. Lastly, if you can, use one mascara at a time, so you really get your money's worth of product (especially for department store mascaras, those are $18CAD - $31 a pop!).
I'll talk more about the expiry of cosmetics products in a later post. In the meantime, anyone else kept a mascara longer tan the manufacturer's suggestion? What's the longest you've kept your mascara? No worries, I won't judge... like I said, I used to keep mine forever, haha.
xox,
ysobel