niacinamide and glycolic acid

Niacinamide and Glycolic Acid | 2 Myths Busted + How To Layer

Ever heard that you can’t layer niacinamide with acids? Are you wondering if there is any truth to it? Niacinamide and glycolic acid are two popular skincare ingredients that can do wonders for your skin, but can you use them together?

Here’s everything you need to know…

Niacinamide and glycolic acid together



Niacinamide is a water-soluble form of vitamin B3 that acts as an antioxidant and has a wide-range of benefits for your skin, including:


  • Reducing the appearance of enlarged pores
  • Controlling oil production
  • Reducing hyperpigmentation (dark marks, age spots, melasma, etc.)
  • Brightening skin
  • Reducing inflammation and redness
  • Improving acne
  • Improving skin barrier strength by encouraging the natural production of ceramides.
  • Boosting collagen production to improve fine lines and wrinkles
  • Helping to protect skin from sun damage and skin cancer


It’s one of those all-rounder skin ingredients that does pretty much everything and is suitable for all skin types.


Glycolic Acid

Glycolic acid is an alpha hydroxy acid (AHA) that is made from the sugar cane plant. It acts as a chemical exfoliant to weaken the bonds between dead skin cells and enable them to be shed from the surface of your skin. Some of the benefits of AHAs like glycolic acid include:


  • Improving skin texture
  • Reducing hyperpigmentation
  • Brightening skin
  • Improving acne
  • Boosting collagen production to improve fine lines and wrinkles
  • Reducing the appearance of enlarged pores


Glycolic acid has the lowest molecular weight of all the AHAs which means that it penetrates your skin with more ease. However, because of this, it’s also more likely to cause skin irritation.


Can You Use Niacinamide and Glycolic Acid Together?

Niacinamide and glycolic acid both offer similar benefits and may compliment each others effects, particularly when it comes to:


  • Treating acne
  • Improving fine lines and wrinkles
  • Reducing the appearance of large pores
  • Brightening skin


Another benefit of using niacinamide and glycolic acid together is that niacinamide can help your skin tolerate irritating skincare ingredients like glycolic acid.


You can read about how niacinamide reduces retinol-induced irritation here.


Niacinamide encourages your skin to produce more lipids, which are the substances that hold your skin cells together. When your skin is lacking lipids, it’s easier for water to escape and irritants to enter.


By encouraging the natural production of lipids, niacinamide helps strengthen your skin barrier and reduces the risk of irritation commonly experienced when using chemical exfoliants.


However, you may have heard that you can’t use niacinamide and glycolic acid together because they have different pH levels. Glycolic acid is most effective when at a pH of 3.5 or less, while niacinamide’s pH is closer to neutral (5.0 – 6.0). 


There seem to be two main concerns when it comes to combining niacinamide and glycolic acid together:


1. Niacinamide may increase the pH of glycolic acid and therefore make it less effective.


2. Acidic ingredients, like glycolic acid, may convert niacinamide to niacin (nicotinic acid).


Will Niacinamide Reduce The Effectiveness of Glycolic Acid?

First things first, your skin’s natural surface pH is slightly acidic with a pH level anywhere between 4.7 – 6.0. Any skincare product you apply to your skin has to adjust to this pH and is usually formulated with this in mind.


When you hear people talk about differing pH levels in skincare, it’s usually a misunderstanding about how skin care product formulation works.


For example, a glycolic acid product will be more effective if the formula has a pH of 3.5 or less, NOT if your skin has a pH of 3.5 or less.


As niacinamide has a similar pH to your skin, it won’t make glycolic acid any less effective than your own skin would.


There’s also research to suggest that glycolic acid is still effective at a pH of 4.4.


The issue of pH differences only becomes a problem when formulating products that contain niacinamide and glycolic acid together.


Will Glycolic Acid Convert Niacinamide To Niacin?

Niacin may be as effective as niacinamide, but it activates your skin’s immune system (Langerhan cells) which leads to the release of substances (prostaglandins) that increase inflammation and blood flow to your skin.


This facial reddening is often referred to as ‘niacin flush’ and can cause an uncomfortable or tingling sensation.


Many people avoid layering niacinamide and glycolic acid for this reason. However, niacinamide is a very stable ingredient and it takes a very low pH, a very high heat, and a long time to convert niacinamide to niacin in laboratory experiments.


(if you want to read about this in more detail, check out KindofStephen’s post on combining vitamin C and niacinamide)


So, again, this is more of an issue when it comes to multi-ingredient product formulation than with layering niacinamide and glycolic acid together. If you’re worried about niacin flush, be careful when using skincare products that contain niacinamide and glycolic acid in the same formula.


However, if you are layering niacinamide and glycolic acid together as two separate products, then it’s unlikely you need to worry.


How To Use Niacinamide and Glycolic Acid Together

Now that we’ve discussed why it’s fine to use niacinamide and glycolic acid together, what’s the best way to go about it?


The most important thing to remember is that you should only ever introduce one active ingredient at a time. This is for two main reasons:


  • To avoid skin barrier damage and irritation
  • To work out whether a skincare active is agreeing with your skin or not


So which goes first, niacinamide or glycolic acid?


It’s mainly down to personal preference which ingredient you introduce first. However, I would recommend using niacinamide twice a day (at 2-5% concentration) for a month before introducing glycolic acid. Research suggests that using a moisturizer containing niacinamide for a month before starting retinol helped prevent skin irritation so it’s likely it would help prevent glycolic acid irritation too.


Once you’re using both, you can either use them at separate times of day (e.g. niacinamide in the morning and glycolic acid in the evening), or layer them together.


If you’re planning on layering niacinamide and glycolic acid together, then it depends on the type of products you’re using as well as your personal preference. For example, a general rule of thumb is to apply your skincare products from thinnest to thickest. 


So, if you were using a glycolic acid toner and a niacinamide serum, you would use glycolic acid first. If you’re using both as serums, then it doesn’t really matter which way round you use them as long as you’re applying your glycolic acid to dry skin (to reduce the risk of irritation).


However, the thinnest to thickest rule isn’t set in stone. In fact, if you have sensitive skin, then you may want to apply a niacinamide moisturizer before a glycolic acid serum so that it takes longer to penetrate your skin (the ‘buffer’ technique).


You can also take it one step further and apply your niacinamide moisturizer before and after your glycolic acid serum (the ‘sandwich’ technique).


Summary – Can You Use Niacinamide and Glycolic Acid Together?

Yes, you absolutely can layer niacinamide and glycolic acid. In fact, they would likely complement each other’s effects. Just be sure to only add in one ingredient at a time and, as always, wear sunscreen!


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