Why You Should Only Apply Antioxidants at Night

Episode #138 / Dec 23, 2009
For topical antioxidants to work most effectively, you should apply them at nighttime. Dr. Schultz explains why.
Sarah on December 29, 2009 at 4:23am

Hi Dr. Schultz,
I've been using a topical antioxidant serum as well as a topical acne treatment Rx (Differin and Duac). If antioxidant's work best at night, does this mean I need to apply them instead of the acne treatment? Would layering them reduce their effectiveness?

Thank you!

Carolyn on January 4, 2010 at 7:30pm

Dr. Schultz,

I use Skinceuticals CE Ferulic antioxidant serum. This is how Skinceuticals tells you to use the product:

"Once in the morning after cleansing, apply 4-5 drops to a dry face, neck and chest. Follow with SkinCeuticals Hydrating B5 Gel and a SkinCeuticals moisturizer and sunscreen."

So why is it that the manufacturer tells you to use it in the morning if the benefits of it are going to be destroyed by the sun?


Anna on January 5, 2010 at 9:30am

For those of us that use retin-A at night - how can we apply the antioxidants at night aswell? I thought they weren´t compatible?!

thank you

Neal Schultz, M.D. on January 15, 2010 at 6:46pm

@Anna: Retin-A’s incompatibility is based on the fact that it is very fragile and easily altered or destroyed by acids but not esters and other compounds. If your antioxidant is ascorbic acid (an acid), then they can’t be used together, but many antioxidants are not acids and then are compatible with Retin-A, in which case, they can be used together, provided that they are applied in the proper order (see In What Order to Apply Your Skin Care Products for more info on the order of application).

[UPDATE: A very observant viewer, Jae, noticed a conflict between my statement above - that you can't use a product with ascorbic acid with product containing a retinoid and my stating in the comments of DermTV episode #180, Can You Use Retin-A and Antioxidants that you can in fact use SkinCeuticals Phloretin CF (which contains ascorbic acid) with a retinoid. Let me explain… You are correct that I stated, “If your antioxidant is ascorbic acid (an acid), then it (Retin A and ascorbic acid) can’t be used together.” When I said that I was lumping all acids (including ascorbic acid) together to try to simplify a complex issue. The relative incompatibility between retinoids and acids is directly proportional to the strength of the acid; the stronger the acid, the more injurious it is to the fragile Retin A molecule. Ascorbic acid is such a weak acid that it probably can not damage Retin A (as opposed to most Alpha Hydroxy and Beta Hydroxy acids, eg. glycol, salicylic, etc.) which are much stronger and will inactivate the Retin A. So in fact you can use products with ascorbic acid with Retin A. Sorry for the confusion.]

Neal Schultz, M.D. on January 26, 2010 at 4:45pm

@Carolyn: I think that your question about that specific product would best be directed to its manufacturer in terms of why they suggest using it during the day. But, as you know, I suggest applying them during the night. I recommend antioxidants as part of an anti-aging regimen because they have been shown to effectively destroy harmful energy from being released within and damaging your skin's cells, DNA, etc. In order for them to do this, they need to be properly absorbed into your skin. If they are applied during the day, while they will effectively absorb and destroy the harmful UV rays of the sun, they will also be destroyed in the process even before having a chance to be absorbed into the skin's cells. So, instead of functioning as an antioxidant product, if antioxidants are applied during the day, they'll just function as a sunscreen (and you can just buy a sunscreen if you want a sunscreen, especially considering that they are much less expensive than antioxidants). If, on the other hand, they're applied at night, they have a much better chance to be absorbed into your skin's cells and properly protect it from damaging energy within your skin. Thus, in my opinion, you should use sunscreens during the day to protect you from the sun and antioxidants at night to serve as part of an anti-aging regimen (if you're pursuing one).

Any antioxidant that has become yellow from oxidation is going to no longer be effective. It is unlikely to harm your skin but it is also unlikely to be helpful to your skin. If the antioxidant product is already yellow to start with, then my suggestion is that you assume it has a shelf-life of six months and replace it after six months. To help further the life of your antioxidant, try to protect it from being in direct sunlight and store it in a drawer or cabinet where it is dark rather than leaving it out on the counter in daylight or even artificial light.

Neal Schultz, M.D. on January 26, 2010 at 4:49pm

@Sarah: Properly layering them should not reduce their effectiveness. For information on how to layer your skin care products, see In What Order To Apply Your Skincare Products. Also, there's no reason not to apply one of your acne products in the morning.

Karen on March 16, 2010 at 2:13am

If I use a product w/ ascorbic acid and wait awhile (30 min to an hr) can I use tazorac afterwards? Also, can I layer different types of antioxidants?

Neal Schultz, M.D. on March 17, 2010 at 5:50pm

@Karen: The answer is yes to both.