The Best Skin Care Acids: Types, Benefits and How To UsePosted on 31/05/2018
The term “Acid” tends to have negative connotations however, when it comes to skin care, acids are very beneficial for skin health, rejuvenation, hydration and anti-ageing. Skin care acids are something you should definitely consider incorporating into your daily skin care routine. There are many types of acids that are used commonly in skin care products which can be overwhelming. So we have put together a guide on the best skin care acids – types, benefits and how to use them in your skin care routine.
Alpha Hydroxy Acids (AHAs)
AHAs are the most commonly known skin care acids and are found naturally in foods, milk products and fruits. The most effective and widely used AHAs in skin care are:
- Glycolic Acid: derived from sugar cane and penetrate the skin the deepest.
- Lactic Acid: found in sour milk products. It’s considered more hydrating than Glycolic Acid but doesn’t penetrate the skin as deep. Great for those with sensitive skin. Caution: do not use if you have milk allergies.
- Mandelic Acid: found in bitter almonds. Penetrates the skin the slowest therefore is the most suitable for very sensitive skin types. Caution: do not use if you have nut allergies.
When used in skin care, AHAs act as chemical exfoliators. They are water soluble and essentially “unglue” dead skin cells from the surface layer of the skin and dissolve them. These skin care acids also accelerate skin cell turnover. Once the dead skin cells are removed, AHAs promote collagen production and improve skin elasticity, resulting in healthier, younger looking, new skin. As the top layer of skin is refreshed, your skin texture is smoother and more even toned, wrinkles are less visible and pigmentations /dull spots are lightened.
Skin care products that contain between 5-10% AHA with a pH level between 3 and 4 are considered most effective and gentle. AHAs suit dry, normal and combination skin types. Some Korean skin care products such as the COSRX AHA 7 Whitehead Power Liquid (contains 7% Glycolic Acid) are formulated to also be gentle on sensitive skin. Products that contain more than 10% AHA should be used with caution and only by those who have been using AHA in their routine for a while.
Beta Hydroxy Acid (BHA)
BHAs are also chemical exfoliators however unlike AHAs where there are a few different types, there is only one BHA – Salicylic Acid.
Salicylic Acid is found in foods such as dairy products, fruits & nuts. It functions similarly to AHAs in that it works to dissolve dead skin cells and accelerate skin cell turnover but it is oil soluble. BHA penetrates into the pores and also has anti-inflammatory properties. This means that Salicylic Acid will effectively reduce acne, blackheads and redness as well as help prevent further breakouts. It is great for those with oily, acne prone skin, redness, and combination skin.
Skin care products containing 1-4% BHA with a pH level between 3 and 4 are most effective (1-2% Salicylic Acid is optimal). 3-4% BHA products are more often used for targeting stubborn skin issues and as spot treatments. There are also some more gentle BHA formulas such as the COSRX BHA Blackhead Power Liquid that contains 4% Betaine Salicylate (derived from Willow Bark) which is equivalent to 2% Salicylic Acid.
See before and after results of COSRX BHA here.
Polyhydroxy Acids (PHAs)
PHAs are fairly new acids used in skin care and are known as “second generation” AHAs. This is because they work the same as AHAs but are more gentle and cause less sensitivity to the sun.
How to use Hydroxy Acids (AHAs, BHAs & PHAs)
As chemical exfoliators, these should be used in the exfoliation step of your skin care routine. The exception is if these acids are incorporated into other products e.g. COSRX PHA Moisture Renewal Power Cream or the COSRX AHA/BHA Clarifying Treatment Toner (to be used during moisturising / toning steps). On first use, AHAs and BHAs may cause slight tingling or temporary irritation however this is normal. Best left for approximately 20 minutes for full absorption before layering the rest of your skin care products on.
These acids also increase your skin’s sensitivity to the sun so sunscreen is absolutely essential if these are incorporated into your routine. We recommend using skin care products with higher concentrations of AHAs or BHAs at night rather than in the morning.
Hydroxy Acids can be used at the same time but a patch test should be done first if you have sensitive skin. Alternative ways to use them together include applying BHA on your oily T zone and AHA on your drier U zone if you have combination skin (see skin type guide here). You can also apply one acid in the morning and one at night. If irritation occurs, we recommend to use the acids on alternate nights.
When can you start using these acids: Teenage years onwards.
Hyaluronic Acid is a powerful anti-ageing ingredient found naturally in our skin but as we age, our supply of it decreases!
It functions mainly to retain moisture (a humectant) – having the ability to hold up to 1000 times its weight in water. This creates a moisture barrier on your skin, protecting it from premature ageing. It also has anti-inflammatory properties. Research studies by the NCBI showed that using Hyaluronic Acid for 8 weeks decreased wrinkles by 40%, enhanced skin elasticity by 55% and improved skin hydration by 96% 😱!
You may also see some products containing Sodium Hyaluronate. This has the same benefits of Hyaluronic Acid but is absorbed quicker into the skin and is basically the salt of Hyaluronic Acid.
How to use
Hyaluronic Acid can be found in a lot of products including cleansers, serums, moisturisers and sheet masks. The serums are great because often they are quick absorbing and contain higher concentrations of Hyaluronic Acid / Sodium Hyaluronate (e.g. Klairs Rich Moist Soothing Serum). This acid can easily be incorporated into your skin care routine and is at low risk of causing irritation. Hyaluronic Acid works great with the all the other acids mentioned because it will soothe and hydrate any temporary irritations or dryness caused by them.
Recommended age to start using this acid: 20 years old+.
Ascorbic Acid is pure Vitamin C. It is a powerful antioxidant used in many skin care products and needs to be stabilised to be effective. If the product is oxidised (brownish colour) it won’t work, so it’s best stored in the fridge to prevent oxidisation. The exception is the Klairs Freshly Juiced Vitamin C Drop (contains 5% Ascorbic Acid) which has been formulated so refrigeration is not necessary however storage in a cool, dark place is required.
Many studies support that the benefits of this acid include increasing collagen production, repairing damaged skin including acne scars, brightening pigmentation and protecting the skin against free radicals. Concentrations of this acid ranging from 0.6% – as high as 20% can produce results for the skin. Higher concentrations deliver amazing results but can also be more irritating.
How to use
Ascorbic Acid is mainly found in serums and occasionally sheet masks. This acid is most effective when used overnight and full absorption should occur before applying other products. The exception is when this acid is used together with Vitamin E. Using Vitamin C and Vitamin E together enhances the effectiveness of both vitamins!
We don’t recommended using Ascorbic Acid together with Hydroxy Acids (AHA, BHA, PHA) or Retinoic Acid. These acids on their own are quite strong and using them altogether on the same night (with the exception of AHA & BHA together as mentioned above) will probably cause irritations. In some cases it can also cancel out the effectiveness of Ascorbic Acid.
Recommended age to start using this acid: 20 years old+.
Retinoic Acid (Retin-A) is a Vitamin A derivative in acid form that delivers a direct effect on the skin. It is very strong and requires a prescription. This is different to Retinol which is another derivative of Vitamin A. When Retinol is applied to the skin, it gradually converts into Retinoic Acid, and then begins its magic (see reference). The conversion process can be slow but makes it less irritating than Retinoic Acid.
Retinoic Acid is known to be the ultimate skin care acid. It pretty much has all the benefits of the above skin care acids. Retinoic Acid will stimulate collagen production, fill out wrinkles and leave your skin plump and youthful. It also accelerates skin cell turnover and improves skin texture. It will brighten pigmentation and scarring, heal acne faster as well as refine pores!!!
Retinol delivers the same benefits and is more commonly seen in skin care products available on the market (unprescribed). It can take up to a few months of Retinol use before you see visible results but is the most suitable for those looking for the same benefits in a gentler form.
How to use
Retinoic Acid can cause irritations, peeling, flaking and sensitivity to the sun. Retinoic Acid should be used only as prescribed by your dermatologist.
There are skin care products containing Retinol or have retinol-infused formulas. These products can be incorporated into your routine but still should not be used together with Hydroxy Acids and Ascorbic Acid. They should be introduced to your skin care routine gradually.
Recommended age to start using Retinol: 30 years old+.
Don’t shy away from skin care acids just because it sounds daunting. These acids can do wonders for your skin! If you have tried other means of exfoliation, brightening, hydration and anti-ageing without visible results, consider these acids (with the exception of Retinoic Acid which must be prescribed. Incorporate skin care products containing Retinol instead).
When introducing products containing high concentrations of these acids, it’s important to start slow. Start with 1-2 times a week and gradually build up your usage, allowing time for your skin to adapt. Be aware of which acids can be used together and which should not to avoid reactions.
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Have you tried incorporating any of these skin care acids into your routine? Let us know your favourite acids to use in the comments below!
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