Take care of your vitamin C serum to protect it from degrading or losing effectiveness, and it will take care of you!
Keep it in a dark area.
Vitamin C is susceptible to oxidation when exposed to light, which is why many Vitamin C supplements are packaged in dark-colored glass bottles (brown, blue or green). Always keep your Vitamin C in a dark place and out of direct sunshine.
Keep it covered.
Vitamin C can also be broken down by oxygen. To prevent air from seeping in, always replace the cap and make sure it is tight.
Keep it cool.
Vitamin C can be degraded by high temperatures. As a result, extreme heat exposure should be avoided. It's especially important to think about if you travel frequently and can't always control the product's immediate temperature. Good manufacturers, on the other hand, test their formulas under real-world conditions, and many can maintain formula integrity at temperatures of 30 degrees or higher for short periods of time. However, it is up to the manufacturer, so double-check your product instructions to be safe.