Can you use Lactic Acid and Salicylic Acid Together?

Despite their scary sounding names, acids have established themselves as the most effective and powerful skincare ingredients. With their countless skin benefiting properties you'd be hard pressed to find a formulation without containing any.

There are two main family of acids, Alpha hydroxy acids (AHA) and Beta hydroxy acids (BHA) both of which are chemical exfoliants and can help rid the outer layer of the skin of any build-up of dead skin cells that often lead to a number of skin concerns, from blackheads to the first signs of ageing.

From the collection of AHAs you will often find the most favoured acids used in skincare products are, glycolic acid and lactic acid, the latter is known for being the most gentle and provides skin exfoliation that can be used by all skin types.

As for BHA, there is only one ingredient used in skincare formulas and that is salicylic acid. Compared to lactic acid, you will find salicylic is able to penetrate further into the lower layers of the skin and has the ability to unclog the pores of any bacteria, dirt or excess sebum. With its potent, blemish-fighting properties, salicylic acid has been labelled a powerhouse ingredient for combating acne and other forms of blemishes. Unlike lactic acid, however, salicylic comes with a number of warnings and many have experienced some side effects of dryness, irritation or redness if a product is overused or used incorrectly.

Now that we have briefly touched on these popular skin ingredients we are now going to investigate and answer some questions, such as can you use lactic acid and salicylic acid together? So read on to find out more, and don't forget, if you wanted to learn more about these chemical exfoliants, check out our complete guide to AHAs and BHAs.

Is lactic acid the same as salicylic acid?

Not really, although they are both an acid, lactic and salicylic are not the same. As previously mentioned, lactic acid is a member of the AHA family and is derived from milk. It works on the outer layers of the skin sloughing dead skin cells revealing healthy and glowing cells without any signs of fine lines and flaky patches of skin. Whilst salicylic acid works further down and dissolves any build-up of bacteria, dirt and excess sebum that block the pores resulting in blackheads, whiteheads, spots and other blemishes.

You may also find that both acids work more effectively on different skin types. With lactic acid having a larger molecule size it is not able to penetrate the skin too deeply, making it less likely to cause irritation to the skin. Dry and sensitive skin types would benefit more from using lactic acid, however, consultation with a doctor, dermatologist or other trained professional should take place to ensure it will not cause any harm or damage to the skin.

Oily and blemish-prone skins will find salicylic acid will provide them with impressive results when tackling pesky breakouts and will give the complexion an all-over clarity. Be mindful of how potent the BHA can be when used too frequently as it can leave the skin stripped of vital oils resulting in it kick-starting an overproduction of sebum, leading to more spots and oily skin.

Skin benefits of lactic acid

• Exfoliates the outer layer of skin sloughing away dead skin cell build-up, dirt, debris and excess sebum
• Is one of the more gentle facial acids and can be used by many skin types
• Molecule size is larger meaning it cannot penetrate too far into the skin, causing irritation
• Helps to keep the skin moisturised and hydrated
• Stimulates the production of collagen and elastin in the lower layers of the skin
• Can reduce the appearance of hyperpigmentation and other scarring

Skin benefits of salicylic acid

• Helps to exfoliates the outer layer of the skin
• Is oil soluble and able to penetrate further into the skin targeting clogged pores
• Helps to purify and add clarity to the complexion
• Can reduce the redness and size of active spots
• Most effective ingredient to treat acne and blemish prone skin

There you have some of the benefits of both acids helping you get a clear idea of the differences between them and figuring out which one will benefit your specific skin type.

Can you use BHA and AHA together?

You can indeed! If your skin is comfortable with the use of AHA and BHA, then teaming the acids together should be no trouble! The acids target different areas of the face and often work on opposite layers of the skin meaning you can use both throughout your routine. For example, opting for a lactic acid enriched toner can be applied before a serum containing salicylic acid, leaving your skin feeling soft, supple and any breakout will be reduced.

One point to keep in mind is that when introducing these acids to your skincare routine it should be done slowly after you have performed a patch test. This is easily done by applying a 5p size amount of the product on the inside of your arm and leaving it for 24 hours, if there are no signs of irritation, itching or rash then you are safe to apply the product onto your face. UV sensitivity is also a factor to remember when using facial acids, so applying a daily SPF of factor 30 or above should be the final step of your routine every day, even when it's cloudy.

What can you not mix with salicylic acid?

With the drying effects that often occur when using salicylic acid, it is advisable to not use any form of retinol at the same time. The exfoliation will be too harsh for the skin and can cause a great deal of damage to the skin’s protective barrier. Once this barrier (also called the skin’s microbiome) has an imbalance in the oil and water levels it is unable to effectively protect itself from free radicals, such as UV exposure, pollution and central heating. This will often lead to the skin becoming tight, uncomfortable and congested with signs of ageing becoming more prominent. You can learn more about the skin’s microbiome as we covered it in a dedicated blog post over on our website.

What can you not mix with lactic acid?

Lactic acid is known for being the easiest acid to work with and can be added to any skincare routine with little side effects or irritation caused. Having said that, vitamin C is a skin ingredient that you should avoid using with lactic acid (or any other AHA for that matter) this is not because it will result in a skin reaction. Vitamin C is notoriously unstable and when mixed with other acids will destabilise the pH balance rendering the product useless. This is something to bear in mind when applying your skincare routine, if you are wanting the antioxidant benefits and luminous results that come from using a vitamin C, as well as using formulas contain lactic acid and salicylic acid then alternating the times you apply the products will help.

Vitamin C = AM routine

AHA and BHA= PM routine

This will give your skin the quickest and most impressive results without wasting any product or suffering from any possible skin irritation.

Can I use salicylic acid in morning and lactic acid at night? 

Yes, you can, in fact both ingredients are effective and you are able to use them twice a day. For a morning routine, you can apply an exfoliating toner on cleansed skin that is enriched in salicylic acid. This will help slough away dead skin cells, work deeply in the pores and give the skin all over clarity. The important thing to remember is ensuring you apply a daily SPF for added skin protection. 

Applying lactic acid during your evening routine will have a gentle approach to the skin that some may favour after a day of UV, pollution, and other free radical exposure. With the added benefit of lactic acid providing humectant properties ensuring moisture is locked into the skin surface, this can work overnight whilst you catch up on your beauty sleep. This is ideal to keep the skin plumped, hydrated with the skin barrier's strength fully restored. 

What goes first lactic acid or salicylic acid?

When figuring out the order of skincare application it is often said that you start with the thinnest consistency, such as cleansers and toners, leading up to thicker consistencies such as moisturiser and SPF. This prevents the thicker formulas from creating physical barriers on the skin stopping the thinner products absorbing into the skin. 

The slight difference you have when using an AHA and BHA is the risk of causing some irritation to the skin. This is why it is important to ensure you leave enough time in between applications to allow the skin pH levels to rebalance and prepared for the next step in your routine. If however, you find this still results in irritation, instead try alternating the days you use either acid. This is considered a more harmonious way of reaping the rewards of both acids without any unwanted irritation. 

I hope we have answered some of your questions about lactic acid and salicylic acid today. When adding both to your skincare routine you may find that the two make a more powerful duo than Batman and Robin. If you have questions, please don’t hesitate to get in touch over on our Instagram.