Women always seem to be a bit confused as to whether or not using a primer is necessary. It’s fascinating how many different things primers promise to do and how makeup sales staff will insist it’s an essential step before applying foundation. Here, I’ll break down what primers are, how they function and what to expect from them.

The Promises

The majority of primers claim to do one or more of the following:

1. Diminish the appearance of wrinkles

2. Help makeup last longer

3. Even out skin tone or make it appear brighter

4. Protect the skin from damages of the environment

5. Keep blemishes at bay

Based on the five points above, it would seem pretty important to use a primer.

The truth is that a primer can help with all five of the points above! There are, however, exceptions to each one based on which primer you choose and what your makeup routine is currently like.

As usual, being a professional makeup artist who often thinks marketing claims can be a bunch of bogus, I like to play devil’s advocate and present the pros and cons for you to make the best decision possible.

Here are some things you should know about 99% of primers on the market before you jump right into another purchase. Let’s go through the list of five benefits.

Before Foundation There is Primer

1. Diminish the appearance of wrinkles

Primers have a luxurious, velvety-smooth feeling because of the silicones in them and therefore can fill in indentations (like wrinkles) on the skin’s surface. The reduced appearance of wrinkles is a good, but a temporary effect.

2. Help makeup last longer

At the same time that primer will fill in the lines, it also keeps foundation and other makeup from absorbing and creasing as easily into the nooks and crannies.

The reason makeup lasts longer is because it is sitting upon a layer of silicone molecules and less able to interact with the oils on the skin which would normally cause makeup to wear off throughout the day.

3. Even out skin tone or make it appear brighter

Primers are either invisible, meaning they don’t change the tone of the face, or they have a slight color to help even out skin tone. In the color-correcting category, a longtime favorite of mine had been Smashbox’s Photo Finish Color Correcting Foundation Primer in Green ($38/1oz). Before becoming a green/natural/eco makeup artist, I used this actual green shade to knock down ruddiness before applying foundation.

Whether or not you choose one with color-correcting benefits, the final effect will be as an “invisible” layer on the skin. The good news is since primers are not pigmented or formulated the way a foundation is, it’s a one-size-fits-all-skin-tones product.

4. Protect the skin from damages of the environment

Primers could help you stay protected from environmental damage if they also have antioxidants in the formula. Jane Iredale has a primer called Smooth Affair Facial Primer & Brightener ($48/1.7oz) with a more natural formula that include soothing, hydrating and anti-aging antioxidant ingredients.

5. Keep blemishes at bay

Primers may help with blemishes by protecting the face from makeup that might otherwise clog pores. On the other hand, some people are allergic to or get breakouts from the silicones used in most primers.

The Plastic Wrap Effect

The way that primers can multitask is through the magic of silicones, but you might want to think twice before running out to get a bottle. Silicones – and other synthetic derivations like dimethicone – are the top ingredients in primers with properties similar to plastic. Primers are primarily made up of synthetically created, spherical molecules. These molecules are thought to be inert, meaning without toxic effect to the body, since they can’t be absorbed. The main complaint from environmentalists is that they do not biodegrade.

Of course I have to wonder, maybe as you are, if we should be coating our faces in plastic-like molecules. Consider this: primers’ effects are only temporary; and the particles in which they are comprised could prevent the skin from functioning at the optimal level, and this may ultimately lead to more rapid aging or increased blemishes on the face.

If you have a day in which you need your makeup to really stick and you are going to wear a full face of it, then okay put that primer on! For every day, in my opinion, it’s better to use foundation sparingly and to find quality formulas that look like skin when it’s on so you don’t need to spackle on yet another layer to your face.