Salicylic Acid and Vitamin C | Best Way To Layer.

Salicylic acid and vitamin C are two wildly popular skincare ingredients but which one is right for your skin? Do you have to choose between them or can you layer salicylic acid and vitamin C together?

The short answer is that it completely depends on your skin. However, there are a few key things that can help you decide which is better for you and whether you’re happy to layer them together.

Salicylic Acid

Salicylic acid is beta hydroxy acid (BHA) and chemical exfoliant that’s derived from willow bark.

Chemical exfoliants increase the rate that your skin naturally exfoliates itself. They do this by breaking down the bonds that hold your dead skin cells together which makes it easier for them to be shed from the surface of your skin.

One of the main benefits of salicylic acid over other chemical exfoliants is its ability to penetrate and exfoliate your pores due to its oil-solubility.

It’s also able to:

• Penetrate your oil glands and control the production of oil
• Reduce inflammation and soothe your skin.
• Offer some protection from UV radiation.
• Prevent the growth of bacteria (due to its acidic pH).
• Increase collagen production to improve fine lines and wrinkles.

As it’s an exfoliant you have to be careful not to use salicylic acid too frequently or it could damage your skin’s protective barrier, cause irritation, and make your acne worse (research suggests that acne is associated with skin barrier damage).

Vitamin C

Vitamin C is the most abundant antioxidant in your skin and is essential for the production of collagen. 

More collagen = plumper, younger looking skin.

As well as it’s excellent anti-aging benefits, vitamin C also:

• Reduces dark marks and brightens skin by preventing the activity of the enzymes required for melanin production.
• Reduces inflammation
• Reduces blood vessel dilation and facial redness
• Prevents the growth of ‘bad’ bacteria (the type that cause skin infections and acne)
• Some derivatives of vitamin c can improve the appearance of acne
• Improves skin texture
• Prevents premature skin aging (when used with sunscreen) by neutralising free radicals (substances that damage DNA and break down collagen and elastin)

The most potent and purest form of vitamin C is Ascorbic Acid (AA) – this is the form of vitamin C that is found naturally in your skin and that other derivatives of vitamin C have to convert to in order to exert their effect.

Unfortunately, AA is notoriously unstable and, according to research, must be formulated at pH levels less than 3.5 to enter your skin.

It’s also easily degraded by light and air and should be stored in a dark and cool environment. This degradation is similarly pH dependent, with cream formulations containing ascorbic acid most stable at a pH of 4.

Salicylic Acid vs Vitamin C

Both salicylic acid and vitamin C can help brighten your skin but in slightly different ways.

Vitamin C prevents the activity of an enzyme called tyrosinase.

No tyrosinase = no melanin production.

While melanin helps protect your skin from the sun, your melanin producing cells (melanocytes) are easily triggered which can lead to the uneven distribution of melanin. This is visible on your skin as dark marks and uneven skin tone (hyperpigmentation, melasma, PIH, etc.)

If you’re looking to prevent and treat this then a tyrosinase inhibitor like vitamin C is essential.

Salicylic acid can also help fade dark marks and brighten skin via its exfoliating effects.

One of the biggest issues with vitamin C is that it is notoriously unstable in its active form (ascorbic acid) and is easily degraded by light and air. In contrast, niacinamide is a very stable ingredient which makes it easier to store and use.

There are a wide-range of vitamin C derivatives (e.g. sodium ascorbyl phosphate, magnesium ascorbyl phosphate, etc.) but there’s less research to support their benefits.

Both salicylic acid and vitamin C are effective when it comes to improving the signs of sun damage and skin aging, although, as vitamin C is essential for collagen production, it probably has the upper hand. 

One area where salicylic acid excels over vitamin C is in its ability to treat acne.

A wide variety of research has demonstrated that both over-the-counter salicylic acid products as well as professional peels are incredibly effective when it comes to treating both inflammatory and non-inflammatory acne.

The fact that vitamin C can strengthen your skin barrier may indirectly improve acne as acne is associated with skin barrier damage and reduced ceramide levels – although this is more theoretical. Research has, however, found that the vitamin C derivative sodium ascorbyl phosphate (SAP), was a useful acne treatment.

Can You Use Salicylic Acid and Vitamin C Together?

If you really can’t decide between salicylic acid and vitamin C, there’s no reason that you couldn’t use both together – as long as you don’t find this combination irritating for your skin.

In fact, salicylic acid and vitamin C may be a particularly good combination when it comes to brightening skin.

Skincare ingredients that target hyperpigmentation usually work in one of three ways:

• Before melanin production
• During melanin production (tyrosinase inhibitors)
• After melanin production

In addition, chemical exfoliants, like salicylic acid, can help speed up the fading of existing pigment.

The most effective way to treat hyperpigmentation is by combining ingredients that work at each stage alongside a chemical exfoliant.

For example, retinoids (before), vitamin C (during), niacinamide (after), and salicylic acid (exfoliant).

Research has demonstrated the combination of salicylic acid and vitamin C to be a safe and effective treatment for melasma

Vitamin C can also increase the natural production of ceramides in your skin which helps to strengthen your skin barrier, keep your skin hydrated, and may help reduce any irritation caused by salicylic acid.

How To Use Salicylic Acid and Vitamin C Together

If you do want to use salicylic acid and vitamin C together, you could layer them together or use them at different times of the day.

Vitamin C is best used in your AM routine as it works synergistically with sunscreen to protect your skin from the sun. Salicylic acid also has antioxidant effects but because it’s a chemical exfoliant, it’s better to use it at night when your skin’s natural exfoliation process is at its highest.

Chemical exfoliants, like salicylic acid, should be used a maximum of 1-3x per week in order to prevent over-exfoliation, skin barrier damage, and irritation.

Vitamin C, on the other hand, can be used 1-2x daily. However, at its maximum concentration (20%) it has a half-life of 4 days (it takes 4 days for the level of vitamin C in your skin to decrease by half) so once a day is more than enough to see results.

If you decide to introduce both salicylic acid and vitamin C into your skincare routine, you should only introduce them one at a time. This will help identify if your skin reacts negatively to one of the ingredients as well as helping to prevent skin barrier damage.

Remember to always wear sunscreen!

Salicylic Acid and Vitamin C – The Bottom Line

Salicylic acid and vitamin C are both ingredients that have a wide-range of benefits for your skin – especially when it comes to treating fine lines, wrinkles, and hyperpigmentation. When it comes to anti-aging, vitamin C might just have the upper hand. However, if you have oily skin and/or are prone to acne, salicylic acid would be a better choice. There’s no reason that you can’t use the two ingredients together – as long as you don’t experience irritation.