The Best Skin Care Acids: Types, Benefits and How To UsePosted on 31/05/2018
The term “Acid” tends to have negative connotations but 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. However, the different types of acids commonly used in skin care products can be quite overwhelming. Therefore, we’ve 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 common acids in skin care. Certain foods, milk products and fruits contain natural AHAs. 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. Considered to be 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. AHAs also accelerate skin cell turnover, promote collagen production as well as improve skin elasticity; resulting in healthier, younger looking, new skin. AHAs refresh the top layer of your skin, making it smoother and more even toned. Wrinkles are also less visible and pigmentations /dull spots are lighter.
Skin care products that contain between 5-10% AHA with a pH level between 3 and 4 are the 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 (7% Glycolic Acid) are also gentle on sensitive skin. Products with 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 main 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 instead of water soluble, making it more effective on oily skin. BHA penetrates into the pores and has anti-inflammatory properties. This means it reduces acne, blackheads and redness in addition to helping 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). Products with 3-4% BHA 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.
Polyhydroxy Acids (PHAs)
PHAs are fairly new skin care acids 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 formulated into other products e.g. COSRX PHA Moisture Renewal Power Cream or the COSRX AHA/BHA Clarifying Treatment Toner (use 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 therefore applying sunscreen daily is absolutely essential if you’re adding acids into your routine. We recommend using skin care products with higher concentrations of AHAs or BHAs at night rather than in the morning.
You can apply Hydroxy Acids in the same routine but a patch test is recommended 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 our Skin Type Guide). 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.
Read also: Ultimate Guide On Exfoliation.
Hyaluronic Acid is a powerful anti-ageing ingredient which is already 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 show that using Hyaluronic Acid for 8 weeks decrease wrinkles by 40%, enhance skin elasticity by 55% and improve skin hydration by 96% 😱!
You may also see some products containing Sodium Hyaluronate which has the same benefits of Hyaluronic Acid but is absorbs into the skin quicker. It is basically the salt of Hyaluronic Acid.
How to use
Many cleansers, essences, serums, moisturisers and sheet masks contain Hyaluronic Acid. The essences and serums are great because they have higher concentrations of Hyaluronic Acid / Sodium Hyaluronate and are quick absorbing (e.g. COSRX Hyaluronic Acid Hydra Power Essence).
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 skin care products and needs to be stable to be effective. If the product is unstable i.e. oxidised (brownish colour) it won’t work, therefore 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 a specific formula where refrigeration is not necessary however needs to be stored in a cool, dark place.
Many studies support that the benefits of this acid include increasing collagen production, repairing acne scars, brightening pigmentation as well as 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 skin care acid is used together with Vitamin E. Using Vitamin C and Vitamin E together enhances the effectiveness of both vitamins!
We don’t recommend 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 in the same routine (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. Alternatively, if you wish to use Ascorbic Acid on the same day as AHA, BHA or Retinoic Acid, we recommend using one acid in your morning routine, and the other in your night routine.
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 it is less irritating than Retinoic Acid.
Retinoic Acid is 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 common 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 such as the Missha Time Revolution Night Repair Borabit Ampoule that are widely available. Introduce these products gradually into your skin care routine and avoid using them in the same routine as Hydroxy Acids as well as Ascorbic Acid.
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 trying skin care 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 you can and cannot mix together in the same routine to avoid any 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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Updated 25 March 2019.
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