It’s NOT recommended to use AHA or BHA every day. As a beginner, you may use AHA once every 7-10 days and BHA once every week, maximum. It’s possible to start to increase the frequency to 2-3 times per week once your skin gets used to these acids.
Today, exfoliating acids such as AHA and BHA have become part of more and more people's staple skincare regimes, due to its effective ability to restore the skin.
Our skin naturally removes dead cells every day. However, because of some factors and bad habits, the restoration process of our skin slows down and may come to a point where it completely stops.
This leads to dry, dull, clogged and flaky skin - simply everything we avoid to have!
However, if you're just dabbling in the world of AHAs (Alpha Hydroxy Acid) and BHAs (Beta Hydroxy Acid), things may seem tricky and scary for you because they are actually “acids”.
So, it is important to make sure you are picking the right product and right concentration for your skin.
Because if used incorrectly or too much, these exfoliating acids can bring more harm than benefit to your dear skin.
What AHA & BHA Do to Skin?
Both AHA & BHA have a positive impact on the stratum corneum and can help balance oil secretion.
They work through your skin by dissolving the so-called "glue" that holds your dead skin cells together.
When these dead skin cells are removed from your face, your overall skin will be brighter and softer.
Having dead skin cells is normal, but they can be triggered by pollution, UV rays or freezing winds.
AHA can reach the dermis or corium layer of skin, which can stimulate the proliferation of collagen and elastin to achieve anti-aging effects.
However, AHA is highly irritating, so it may cause irritation, skin allergy or even contact dermatitis.
As for BHA, due to the limitation of its chemical structure, it cannot enter the dermis layer and can only act on the epidermis.
So, BHA cannot stimulate the proliferation of collagen, which also means it doesn’t provide an anti-aging effect.
But there’s a relatively smaller risk using BHA, plus as a synthetic precursor of aspirin, BHA has anti-inflammatory effects.
And that’s why BHA can be a great help for those of you who suffer from acne problems.
After knowing what AHA and BHA can do to your skin, it’s also important to understand what AHA and BHA exactly are to choose wisely for your skin.
What Are AHAs?
AHA or also known as Alpha Hydroxy Acid is a type of water-soluble substances that exfoliates the surface of your skin.
They help the surface of your skin to generate new skin cells, for a brighter and smoother complexion.
Six types of acids are commonly known in the AHA family. Each of them works for different skin types and skin problems.
For example, Glycolic Acid is under the AHA family and it’s extracted from sugar cane.
This acid can soften the outer layer of the skin, which can brighten your skin and smooth the wrinkles.
That’s why Glycolic Acid also has amazing anti-aging effects. Also, you can see an effect quite quickly.
However, due to its small-sized molecule, it can greatly irritate the skin, which means people with sensitive skin should never use it.
For people with sensitive or dry skin, they can approach to Lactic acid, which is also under the AHA family and it’s extracted from milk.
Lactic acid may not work as fast as Glycolic acid, but it’s gentler and its anti-aging effect will show after 4-6 months of use.
People have oily skins should use mandelic acid instead of lactic acid for the best results.
Mandelic acid not only can smooth the wrinkles, but it can also help balance oil secretion and reduce blackheads.
Here is a summary of how different types of AHA (Alpha Hydroxy Acid)works:
SUITABLE SKIN TYPE
Dry or sensitive skin
A mild acid;
Anti-oxidation; lighten fine lines & wrinkles; dissolve dead skin; smooth skin surface
from bitter almonds
Oily, acne and sensitive skins
Lighten fine lines, wrinkles & acne marks; reduce acne and blackheads; balance oil secretion
from sugar cane
Any type of skin (except sensitive skin)
Lighten skin blemishes, discoloration, fine lines & wrinkles; stimulate cell regeneration; smooth skin surface
from apples and pears
Any type of skin (esp. for sensitive skin)
Gentlest acid in AHA family;
Anti-aging; fade discoloration; help unclog pores
from citrus fruits
You need to combine it with other acids to exfoliate skin
As you can see, different types of AHA work very differently and that’s why it’s important to choose very carefully when it comes to AHA.
What Are BHAs?
BHA or also known as Beta Hydroxy Acid is a type of oil-soluble that gets deep into the pores. Unlike AHA, BHA removes excess sebum whilst removing dead skin cells.
The most common type of BHA is salicylic acid, which is extracted from willow bark tree. BHA is ideal for oily, or combination skin and it’s also great for solving acne issues.
BHA has strong anti-inflammation effects and can reduce the excess oil from the skin.
Therefore, salicylic acid has proven to be very effective for treating acne (esp. for closed comedones), blackheads and blocked pores.
SUITABLE SKIN TYPE
from willow bark tree
Oily, combination & acne skins
Anti-bacterial & anti-inflammation; unclog pores, treats acne & blackheads; stimulates collagen production
This type of product can hence gently slough off dead skin cells and accelerates natural exfoliation.
Despite that BHA (more specifically, salicylic acid) is a mild acid, excessive use of BHA will thin your skin layer, which can cause dryness and redness of the skin.
What’re the Key Differences Between AHA & BHA?
As a water-soluble acid, AHA mainly impacts the surface of the skin while BHA can go through the surface to fix the issues in the pore as it is oil-soluble.
In general, BHA is milder and thanks to its anti-inflammation effects, it is very friendly to people with oil, combination or acne skin types.
As for AHA, it’s generally friendlier to dry skins or any skin issues that are related to light exposure, such as wrinkles and skin tones.
Note: BHA can target acne, however, if you want to treat acne scars, BHA won’t help! You may consider azelaic acid or almond acid instead)
When Does AHA or BHA Expire?
AHA (Alpha Hydroxy Acid) or BHA (Beta Hydroxy Acid) will expire in 9 months to 1 year upon opening the seal.
If you use expired AHA or BHA, there will be two consequences:
1) The acid may not harm your skin but it won’t work anymore.
2) The acid can irritate your skin as the buffering agents start to evaporate after the acid is oxygenized.
How Should You Apply AHA or BHA?
Exfoliating acids are considered as a double-edged sword. If used right, they'll help you achieve that perfect skin that we all long for.
But if overused, it'll punish your skin with dryness and irritation.
If you are new to certain acid, it’s suggested to start with a low concentration and gradually increase the concentration as the adaptability of the skin increases.
Once you start to feel the effect, it’s better to stop increase concentration.
For those of you using acids to smooth wrinkles, it’s fine to have long-term use as long as the concentration level is low.
However, for those of you who want to cure or improve acne, it’s better to stop using the acids once your acne is cured.
Otherwise, the acids, either AHA or BHA, may cause skin irritation, redness or even some permanent issues.
Generally, you will start to see some effect after 4-6 months of use.
Make sure you only use them at night after cleaning the face. It’s suggested to avoid using acid during daylight because any acids, no matter how low the concentration is, will make the skin weak, hence, it can be sensible to ultraviolet.
If you're wondering whether you can use your AHA or BHA products every day, the answer is NO and the frequency lies on your skin type and the type of exfoliating acid that you're using.
Your age is also a determinant:
• Ages 20* - it is advised to use a glycolic acid 5% for normal, dry, dehydrated or combination skin. For oily, acne-prone or combination skin, you can use salicylic acid 0.50%, three-four times per week.
• Ages 25-45* - at this your skin can tolerate 10% of glycolic acid, 0.5 - 2% of salicylic acid for acne-prone and oily skin types. For sensitive skin, it is suggested to do a patch test first before applying the product to your whole face.
• Ages 45 onwards* - you can try 10% of glycolic acid for daily use, or a 30% chemical peel once or a week. For oily and acne-prone skin, you can use a salicylic cleanser once or twice a day, and follow it up with a 10% glycolic acid toner or serum every other day.
*These are just suggestions based on experience. As always, you should start from low concentration for any acids and test little by little on your skin.
"Overusing AHAs & BHAs can burn your skin and leave them more vulnerable to the sun. It will also thin out your skin and promote premature aging to your skin. "
What Are Signs That You Have Overused Exfoliating Acids?
As mentioned above, it’s recommended not to use acid every day. However, it depends on each individual to find what is the best frequency.
Therefore, there are possibilities that you may overuse AHAs or BHAs, especially if you are a beginner.
Here are the signs that you have overused your exfoliating acids:
- Redness and irritation
If you experience any of the above signs, please stop using the product immediately and let your skin recover by itself. It usually takes 10-15 days to remover.
The rules I am talking about here only applies to skincare products. The following two types of products are exceptions:
• Exfoliating Cleansers - as for cleansers, they are safe for everyday use. They won't stay on your skin for too long since you'll be having to rinse them off after a couple of seconds.
• Chemical Peels - you can only use them once every 10 – 15 days. Chemical peels are way more concentrated than acid toner or serum.
They also contain more percentage of acid--which makes them unsafe for daily use.
How to Incorporate AHA or BHA in Your Skin Routine?
As for the sequence in your skincare routine, you can apply your exfoliating products after cleansing and toning your face, before you apply your moisturizing gel or lotion.
Exfoliating acids like AHA and BHA are on your aid to help you get a smoother and brighter complexion.
But it is important to keep in mind that these acids can also irritate and dry out your skin when overused.
So, use them in moderation, depending on your age and skin type.
Skincare is not meant to be complicated. You'll just be having to know your skin type well, and the formulation of the products that you're using.