This is why your makeup oxidizes, plus six tips on how to prevent it

Have you ever swatched foundation in the store, fell in love, and purchased it only to discover that it had turned darker (or worse, turned orange!) when you got home? If this sounds familiar, you've experienced having makeup oxidize on you. This is why beauty reps often ask "acidic po ba kayo?" when you shop face bases, but it's not helpful because the answer is always "yes" as our skin literally has an acidic pH level. What is causing the change in color then?

Oxidation occurs when an element's exposure to oxygen results in a change in its appearance. A good example of this is how apples and potatoes turn brown after being sliced. Everything oxidizes but we don’t always notice it because the rate of oxidation depends on the material. For example, iron reacts with oxygen and turns to rust, but this could take years to happen.

By nature, the minerals in makeup are therefore prone to oxidation. Titanium dioxide, zinc oxide, and iron oxide are three minerals commonly found in makeup. If these minerals are high up in the ingredient list, then the makeup is more likely to oxidize. Titanium dioxide, most especially, is very common as a white pigment, so lighter foundations will have bigger amounts of it. Oxides are not the only ingredients that are prone to oxidation though.

As for the "acidic skin" theory, here's a hard fact: all of us have acidic skin! Normal, healthy skin has to have a low pH level called the acid mantle because the acidity actually protects from bacteria and irritation. However, the level of acidity can range from anywhere between 4.2 to 5.6 so it is possible for some people to be more acidic than others. The makeup combining with our skin’s unique natural oils may also explain varying makeup reactions among different users.

Want to keep your makeup from oxidizing? Here are some tips to help prevent oxidation, or at least slow it down.

Switch your skincare. Having too much oil in the face can contribute to oxidation. If your skin is too oily, try using an oil-reducing cleanser that effectively cleans while maintaining a healthy low skin pH. Likewise, a moisturizer that is too rich can produce the same effect. Try switching to a lightweight moisturizer like the In Her Element Rose Serum Gel Moisturizer (P895 at inherelement.ph).

Use a primer. Having a primer puts a barrier between the skin and makeup, making it less likely for reactions to happen. Some makeup artists believe that silicone primers, being an occlusive agent, provide the best barrier for the skin. The PV girls love Benefit's Porefessional (P1,300 at Benefit)!

Check the ingredients of your makeup. If you haven’t already, try using an oil-free foundation so that the oils of your makeup will not react to the oils of your skin. Also, try to find foundations with antioxidants as these help fight free radicals which cause oxidation. Common antioxidants found in cosmetics include vitamin E, green tea, and resveratrol.

Keep your face oil-free throughout the day. This includes blotting your face before and after applying foundation to prevent oil from seeping through. Blot your face when it feels too oily throughout the day, as well. You may also use an oil-control powder like the Happy Skin Matte of Your Dreams Oil Control Mattifying Powder (P1,200 at Happy Skin) to help control oil on the skin's surface. 

Keep your foundation fresh. Our foundation bottles get exposed to oxygen, too, so it's best to ensure that they're always tightly capped. Liquid foundation typically lasts for about six months up to a year but may oxidize after too long, especially if the container isn't airtight!

Get a lighter foundation. If all else fails and your skin is extra acidic and oily, then it’s time to consider purchasing a foundation in a lighter shade. It takes some trial and error to know how light you have to go, so when you try on a foundation, check how the color changes after a few hours of wear before deciding on which shade is right for you.

Keep in mind that these tips are not foolproof, as everyone’s skin and each product is different. Oxidation is actually not just limited to foundation and can happen will any kind of makeup as well, but it's usually the most noticeable. Follow our tips for flawless foundation for more help!

Have you experienced your makeup oxidizing on you? What did you do to fix it?

Sources: Beautyeditor, Makeupgeek, Paula’s Choice, The Debrief