Feb 18, 2020

Skincare Benefits of AHAs & BHAs - What are AHAs and BHAs?

by Jessica C

It may not surprise some of you to know that 50% of women now research the ingredients in their skincare before purchasing a new product. We are a lot more glued up when it comes to this complicated world of beauty. But do we actually have a good understanding of what these wonderful, skin-renewing products can do for us and our faces, or are we just doing as we are told by all these qualified professionals?

Let me take a little time in explaining in more detail exactly what Alpha Hydroxy Acid (AHA) and Beta Hydroxy Acid (BHA) are and what they actually do for your skin.

What are AHAs and BHAs?

In short, AHA and BHA are exfoliating but unlike manual exfoliants, such as scrubs and brushes, AHA and BHA usually come in a liquid acid form, but don’t let the word "acid" alarm you. Skincare products containing these hydroxy acids, they only contain around 4% concentration of these acids allowing them to be gentle enough for home use. The stronger concentrates are found in treatments such as chemical peels and should only be used by trained professionals to avoid any skin reactions or sensitivity.

Our skin has a natural exfoliating cycle which takes about 30 days to perform. Dead skin cells found on the top layer of the skin shed away to make way for the new layer to be revealed. This cycle will begin to slow down due to ageing and the dead skin cells will begin to build up, this will usually result in the skin looking lacklustre and fine lines becoming more visible.

Chemical exfoliation is a beneficial way of helping the skin’s surface to rid its dead skin cells, which generally leads to breakouts, such as blackheads and spots.

What’s the Difference Between AHAs and BHAs?

AHAs are derived from natural sources, such as milk, sugar cane, apples and many more. They work from the bottom up, meaning they work further down the top layer of the skin, also called the epidermis. They are chemical exfoliants meaning they work at dissolving the bonds of dead skin cells.

There is really only one main BHA and that is salicylic acid, derived from aspirin it has anti-bacterial and anti-inflammatory properties making this acid treat breakouts such as spots and blackheads. This acid works from the top down and is able to penetrate further into the pores and clear out any debris or excess sebum, the natural oil produced by your skin.

There is a great deal more AHAs than BHAs, here is a little more information on these AHA acids.

Glycolic Acid

Glycolic acid is the most researched alpha hydroxy acid and is the most popular acid to be included in skincare products. Glycolic acid is derived from sugar cane and other plants and fruit, such as pineapples. The molecule size of this acid is the smallest known allowing it to penetrate through the layers of the skin resulting in skin concerns, such as fine lines and wrinkles to become less visible over time. Applied onto the outer layer of the skin, the epidermis, allows glycolic acid to loosen the bonds of dead skin cells removing them revealing a revitalised, glowing complexion underneath.

Professional chemical peels use glycolic acid in order to see a marked improvement in the skin's texture and overall appearance, that being said using glycolic acid for home use is still safe ensuring a lower concentrate of 1-6% is used in comparison to the professional amount of 20-30%.

Key Benefits of Glycolic Acid

Glycolic acid is one of the most popular AHAs and is found in many skincare products for home use and professionally performed chemical peels.
Glycolic acid concentrates are reduced from 30% to a maximum of 6% to make them safe to use at home.
Glycolic acid reduces the appearance of fine lines and wrinkles.
Glycolic acid can combat the complexion from looking dull and lacklustre restoring vibrancy to the skin.
Glycolic acid evens out the skin's texture making it appear smooth and supple.

Hyaluronic Acid

You will find Hyaluronic acid naturally occurs in the body, found in the epidermis layer of the skin. Its role in the skin is to hydrate, plumpen and maintain the elasticity of the face. The molecules of hyaluronic are able to hold one thousand times their weight in water, this level will be maintained throughout the day.

Much like collagen in the skin, hyaluronic acid production decreases as we age. By adding products enriched with hyaluronic you are able to maintain the right levels of moisture in the skin.

Dehydrated skin is regularly mistaken for a skin showing the first signs of ageing. Due to the face lacking in hydration, it appears dry with fine lines and wrinkles. Topically applying a serum or moisturiser containing hyaluronic acid will plump up thirsty looking skin and iron out the lines.

Key Benefits of Hyaluronic Acid

Hyaluronic acid appears naturally in the body and can maintain moisture in the skin
Hyaluronic acid production begins to decrease as we age.
Hyaluronic acid locks moisture into the skin making it plumped and young-looking.
Hyaluronic acid production can be disturbed by poor diet, eating lots of fruit and vegetables rich in antioxidant will maintain it.
Hyaluronic acid is added to many skincare products to help with anti-ageing.
Hyaluronic acid works well in conjunction with other facial acids.
Hyaluronic acid is suitable for all skin types.

Citric Acid

As its name may suggest, citric acid derives from citric fruit extracts, such as oranges, grapefruit, lemons even some berries. Much like the other AHAs, it is able to chemically exfoliate the skin by dissolving the bonds or "glue" that hold dead skin cells together.

Something that is different about citric acid is the antioxidant properties which are able to protect the skin's barrier from daily and environmental aggressors, such as pollution and UV rays. It is also found in many skincare products due to its ability to balance the pH levels making other ingredients stable, making them safe use. If you find you have enlarged pores and skin that tends to be on the oily side, citric acid will be beneficial for you to add to your routine in order to keep pores clear and blemishes to the minimum. Sensitive skins that are prone to redness may need to avoid using citric acid and instead find an acid more suitable.

Key Benefits of Citric Acid

Citric acid exfoliates the skin, removing the bonds of dead skin cells that can lead to breakouts and other blemishes
Citric acid is full of antioxidants and fights against daily aggressors that can harm the skin's barrier, such as pollution.
Citric acid works on the pigmentation of the skin giving an all-over even complexion.

Lactic Acid

Lactic acid derives from the lactose of milk and is a great starting point for any of you who are wanting to try an AHA or have never tried chemical exfoliation before as it is one of the most gentle.

Lactic acid has one of the largest molecules in comparison to the other hydroxy acids featuring in this guide. It is water-soluble which results in it working on the outer layer of the face and will work away dead skin cells revealing a brighter complexion. Lactic acid is easily added to the formulas of skincare products, such as cleansers, serums and moisturisers but it is also used in many professionally performed chemical facial peels.

Key Benefits of Lactic Acid

Lactic acid is made naturally in the body but is made from the lactose of milk when formulated in skincare products.
Lactic acid is one of the more gentle AHA available to use.
Lactic acid exfoliates helping to improve the appearance of dry skin.
Lactic acid is used in professional chemical peels
Lactic acid can help reduce fine lines, wrinkles and enlarged pores
Lactic acid can increase sensitivity to the sun's UV rays.

Malic Acid

Made from fruits, in particular apples, malic acid is unusual due to the fact it isn’t effective as a stand-alone acid, instead if it is teamed with other acids, such as lactic or glycolic, it can make them more effective.

However malic acid also has beneficial qualities on its own accord for helping reduce the signs of hyperpigmentation such as dark spots from sun damage or blemishes, it does this by reducing the overproduction of melanin. It works on the outer layer of the skin improving the skin's vitality such as its suppleness and elasticity. Malic acid also helps unclog pores, promotes the natural collagen production of the skin and reduces the appearance of fine lines and wrinkles.

Key Benefits of Malic Acid

Malic acid exfoliates on the outer layer of the skin giving it an overall, glowing complexion.
Malic acid reduces any visible darks spots and hyperpigmentation whilst slowing down the production of melanin.
Malic acid unclogs pores and prevents breakouts and blackheads.
Malic acid works very well teamed with other AHAs.
Malic acid is less irritating than other hydroxy acids available and is found to work on skins that can become irritated easily.

Ascorbic Acid

This is the most common water-soluble form of vitamin C and delivers impressive results when treating melasma. It's a potent antioxidant with skin-smoothing properties that help with the appearance of wrinkles and other signs of skin ageing. When mixed with other antioxidants it becomes a powerhouse for treating the skin. As a stand-alone acid, with high percentages of 20%, it is able to even out skin tone and reduces the pigment of dark spots.

However, ascorbic acid is very unstable in the presence of oxygen and water. With overexposure to UV rays, it will also begin to discolour and become a dark brown with no potency left for it to perform as it normally does. It is a good idea to remember this when looking for a product that contains ascorbic acid and avoid any skincare products that are in glass jars.

Key Benefits of Ascorbic Acid

Ascrobic acid is an antioxidant that can be combined with other antioxidants to protect the skin's barrier for free radicals.
Ascorbic acid has skin healing properties and has the ability to trigger the production of elastin and collagen
Ascorbic acid is a form of vitamin C which helps reduce the appearance of pigmentation and evens the overall tone of the skin.
Ascorbic acid tackles signs of ageing, such as fine lines, wrinkles and sagging of the skin.
Ascrobic acid becomes a powerhouse ingredient when combined with other antioxidants.
Ascorbic acid is found in many skincare products, the most effective product is however serums.

Tartaric Acid

Tartaric acid is derived from grapes and much like the other Alpha Hydroxy Acids is a powerful antioxidant and exfoliant to help with the overall texture, tone and luminosity of the skin. Just like better known AHAs, tartaric acid works on the upper layer of the skin and haven't got the strength to penetrate down the bottom layers into the pores. This means tartaric acid can shed the layer of dead skin away from the face revealing the new skin cells underneath making the complexion brighter and younger-looking.

Tartaric acid isn't as well researched as other acids, such as lactic and glycolic, and is still known for not being very stable. However, a laboratory environment studies have shown that tartaric acid broken down into its derivations called tamarinds, they are able to take on the form to chemically mimic the skin's ceramide structure. It is unknown if this can be adapted to being used in cosmetic procedures and products. Tartaric acid is also proven to keep the pH levels of the skin balanced, it can also give other acids, such as glycolic, can strengthen their exfoliating abilities.

Key Benefits of Tartaric Acid

Tartaric acid is derived from fermented grapes.
Tartaric acid can be added to other acids and formulas to strengthen their sloughing power.
Tartaric acid is not as researched as other AHAs but has many studies showing it's many benefits in skincare.
Tartaric acid balances the pH levels in the skin which can become irritated easily with other facial acids.
Tartaric acid can even out the skin's tone and brighten the complexion
Tartaric acid is gentle enough for all skin types to use in low percentages.

Mandelic Acid

Mandelic acid is made from bitter almonds and has a considerably larger molecule size and structure than other alpha hydroxy acids. This results in its penetration of the skin is a lot more shallow than the other AHAs making it very suitable for sensitive skin types to use due to the less risk of irritation to the skin. Darker skin tones who find AHAs too irritating for the skin and lead to the overproduction of melanin are able to use mandelic acid and see a noticeable difference in any areas of melasma and other darker pigmentation on the skin.

Mandelic acid works by helping to improve exfoliation by lowering the risk of skin irritation when combined with other acids such as glycolic, lactic and even the BHA, salicylic acid. That being said, mandelic acid is not potent or strong enough to perform this as a stand-alone product.

Key Benefits of Mandelic Acid

Mandelic acid is derived from fermented grapes and has a larger molecule structure of any other AHAs.
Mandelic acid is able to reduce the appearance of melasma by up to 50%
Mandelic acid has a shallow penetration compared to other acids meaning it is ideal for sensitive skin types to use.
Mandelic acid combined with other acids, such a glycolic, can aid the exfoliation and increase the speed of cell turn over, making the face appear brighter and younger-looking.

Azelaic Acid

Azelaic acid is derived from wheat, rye or barley and is actually neither an AHA or a BHA yet is still considered a member of the acid family. With many properties such as being anti-inflammatory and antibacterial is has been proven to help treat spots and breakouts whilst also being very effective at treating rosacea due to it being able to kill off any forms of bacteria known for causing inflammations.

Azelaic acid can also help with any dark spots from acne scarring or sun damage, especially in darker skin tones. This acid also helps prevent the overproduction of melanin which causes hyperpigmentation of the skin, such as melasma. Many pregnant women suffer melasma and breakouts throughout their pregnancies and azelaic acid has been proven to be safe enough to use during pregnancy and nursing mothers.

Key Benefits of Azelaic Acid

Azelaic acid has antibacterial and anti-inflammatory properties in it meaning it is able to treat breakouts, such as spots, and rosacea
Azelaic acid can be made from wheat, barley or rye.
Azelaic acid is technically neither an AHA or BHA but is still considered a member of the acid family.
Azelaic acid has been proven to be safe enough to treat melasma and breakouts in pregnant and nursing mothers.

Oleic Acid

Oleic acid is considered a true godsend when you have dry, tight and uncomfortable skin. You have no doubt heard of omega fatty acids before and these and oleic two of the same thing. This fatty acid is naturally produced in the body and olive oil is known for being abundant with oleic acid. This particular AHA is fantastic as reviving and bringing dry skin back to life as well as adding much need hydration to mature skin.

Oleic acid penetrates easily into the skin's surface layers replenishing any lost moisture whilst stopping it from evaporating without clogging the pores. Fine line and wrinkles are reduced and the skin is saved from sagging and losing its bounce. A free radical fighting antioxidant, the skin's barrier is protected from environmental aggressors, such as pollution and UV rays that are two of the main triggers of premature ageing of the skin.

Key Benefits of Oleic Acid

Oleic acid is naturally produced in the body and can also be found in fatty acid-enriched oils such as olive oil.
Oleic acid is a powerful antioxidant that protects the face from free radicals that cause the skin to prematurely age.
Oleic acid is extremely moisturising and hydrates very dry skin and mature skin and stops any moisture evaporating from the skin.
Oleic acid has antioxidant properties and can calm, neutralise and promotes the skin to heal from inflammations. This makes it suitable for eczema-prone skin to use.

Kojic Acid

Kojic acid is made by using fermented rice during the making of sake. This acid prevents tyrosine from forming on the skin, these are a type of amino acid that is required for the production of melanin. Having said this, kojic is an amazing lightening any pigmentation found on the skin. It mainly used on the face, hands and other none sensitive areas to help even and brighten the complexion. This acid is used mainly by Asian cosmetic brands and found in face powders, toners, serums and face creams.

Due to the strength of kojic acid, it is not advisable to use on sensitive skin types that are prone to redness. By law, the concentration of this acid is limited to 1% and is considered safe to apply in at-home skincare products. However, some may still find the acid too strong and will suffer from itchy, flaky rashes on the skin. If this occurs discontinue the use of the product.

Key Benefits of Kojic Acid

Kojic acid is made from fermented rice collected during the production of sake.
Kojic acid is highly effective at brightening the skin and evening out skin tone suffering from hyperpigmentation.
Kojic acid can cause some skin irritation and shouldn't be used by sensitive skin types.
Kojic acid is very popular in Asian cultures and features a lot in makeup and skincare products.

Linoleic Acid

Linoleic acid is very similar to the previous acid, oleic acid and is highly moisturising for the skin. However, unlike oleic, linoleic acid does not occur in the body. It is found in cactus and is able to lock in moisture to the skin whilst preventing any inflammation to the skin.

Linoleic acid differs from oleic acid in other ways as it doesn't penetrate as far down the layers of the skin like oleic is able to. It is also the less moisturising of these two AHAs. However, teaming these acids together give you a super hydrating duo which locks in moisture, heal and protect the skin from harsh environmental elements.

Key Benefits of Linoleic Acid

Linoleic acid doesn't naturally occur in the body, unlike oleic acid, it is found in cactus plants.
Linoleic acid hydrates and stops moisture from evaporating from the skin, this makes it highly beneficial for dry skin types.
Linoleic acid becomes highly effective when teamed with other AHAs, especially oleic acid.

Lipoic Acid

Lipoic acid, or rather alpha lipoic acid is a powerful antioxidant and can ward off any free radicals that can cause infection and viruses. You will find lipoic acid in every cell in your body, much like other cells the production speed begins to slow down and becomes less effective at keeping the skin and body at its healthiest.

Lipoic acid is powerful enough to regenerate the body's natural system of antioxidants, allowing your skin to maintain the power to fight off toxins and other aggressors that can cause damage to the protective skin defence barrier. ALA (alpha lipoic acid) is such a powerful antioxidant, it is 400x stronger than vitamin C and vitamin E combined. It also helps keep the potency of these vitamins at the highest levels meaning skin concerns, such as redness, inflammation, loss of firmness, enlarged pores and wrinkles are treated effectively.

Key Benefits of Lipoic Acid

Lipoic acid naturally occurs in every cell of the body
Lipoic acid is one of the strongest antioxidants known.
Lipoic acid has been proven to enhance the benefits of vitamins C and E
Lipoic acid aids moisture to be locked into the skin.
Lipoic acid allows the skin to become more supple and youthful-looking.

Ferulic Acid

Ferulic acid is generally derived from cereal grains and can also be found in other foods oat, rice and even apple seeds. In comparison to other AHAs, ferulic acid is proven for its skin treating properties and currently, studies being carried out to see if there any other benefits too. This acid can be applied topically and also in oral supplement form.

In serums, ferulic acid tends to work best with other antioxidant ingredients, particularly vitamin C. Vitamin C is highly beneficial for treating uneven skin tone, however, when left alone doesn't have a long enough shelf life. This is why you will usually find vitamin C enriched serums in opaque or amber coloured bottles. By adding ferulic acid to the formula the potency of vitamin C remains powerful and discolouration doesn't occur as quickly.

Key Benefits of Ferulic Acid

Ferulic acid is derived from cereal grains, bran, oats and apple seeds.
Ferulic acid is added to serum formula containing vitamin C to keep the product shelf-stable.
Ferulic acid aid the effectiveness of other antioxidants to perform properly.
Ferulic acid fights off free radicals that cause the skin to prematurely age.

Salicylic Acid

Salicylic acid is also known as a beta hydroxy acid or BHA is derived from aspirin, however it has also been known to be made from willow bark. This acid differs from the ones previously mentioned. It also provides exfoliation but due to the fact salicylic acid is oil-soluble, it is able to work further down into the skin's layers penetrating into the pores targeting any excess sebum and bacteria. Inflammations are also reduced and the complexion is left healthy and balanced.

The skin types that would benefit the most from salicylic acid are oily and blemish-prone. However, overusing this acid can result in your skin becoming dry and irritation resulting in flaking rashes. It is best to monitor how your skin is coping with the application of salicylic acid.

Key Benefits of Salicylic Acid

Salicylic acid is derived from aspirin or willow bark, those who have an allergy to aspirin should avoid using it.
Salicylic is the only known BHA and is different from AHA
Salicylic acid is oil soluble and works further down in the skin and can unclog the pores and remove any bacteria, dirt and excess sebum that can lead to breakouts.
Salicylic acid exfoliates the skin giving the face an overall healthy complexion.

For more information read our detailed guide on Salicylic Acid to learn more.

From all the AHAs and BHAs available out there, the ones mentioned above are most commonly used in skincare products.

What Do AHAs Do for My Skin?

Alpha Hydroxy Acids (AHAs), can be found in a lot of skincare products, from serums, toners, cleansers and professional peeling treatments. Primarily, the main job of AHAs is to exfoliate the skin, however, this is only one of the benefits, AHAs are also able to;

Improve the overall texture of your skin
Brighten the complexion
Promote collagen production
Even skin tone from discolouration, such as sun damage and acne scarring
Prevent breakouts
Allow following skincare products to absorb quickly into the skin

There are a couple of ways of introducing alpha-hydroxy acids into your skincare routines, such as serums, toners or cleansers, also not forgetting the professional chemical peels.

How to Use AHAs

To ensure you are getting the most out of using AHAs on your skin, here are some tips and advice on how to use them and which skin types benefit the most from the application.

Remember that AHAs work best for skin that is generally drier, they are able to exfoliate the skin and help level the moisture intake for your skin. Sun-damaged skin is also helped mostly from AHAs such as lactic and glycolic acid.
If you are using a product, such as a serum, containing AHAs you are able to bring the product up to under the eyes, however, avoid putting it on the lid or lash line.
You don’t need to wait for the AHA to absorb into the skin, continue applying your skincare routine as normal.
Experiment with the concentrate levels of the acid once your skin is used to it. This will keep the acid working well on your skin.
Use the acids as much as your skin needs, some skin can take using a medium concentrate product morning and evening, while others benefit more from 2-3 times a week.
Don’t forget to take acids down onto your neck and chest. For the rest of your body, there are some washes and lotions available that contain lactic acid which is great at moisturising and giving some vibrancy back to the body.

You will have the best understanding of your skin and with some experimenting, you will find the right acid for you. Like any product, if there is irritation, stop using it and ask for some advice from your pharmacist.

What Do BHAs Do for My Skin?

As previously mentioned in this guide, the main BHA out there is salicylic acid. This is what to expect when using this acid.

BHA works best for oily skin types
Blemish prone skin will also be benefitted from using this acid due to fact it works deeper into the pores and unclogging any debris that leads to spots
Combats enlarged pores
Can treat rosacea-prone skin too because of the anti-inflammatory properties.
Not suitable for anyone who has an allergy to aspirin

Adding salicylic acid to your routine is an easy way of cleaning your skin. Due to oily skin types finding the need for their skin to feel squeaky clean can lead to using products, such as scrubs and brushes, that can sometimes be too abrasive for the skin and strips the skin of the natural oil, called sebum. This then, believe it or not, leads to excess oil being produced. With salicylic acid working further down the skin layers and unclogging the pores, the clean feeling is achieved without it being too harsh!

How to Use BHAs

Unsurprisingly you are able to use a BHA in a similar way to AHA, here are a few differences you may find when trying salicylic acid on your face.

You’ll find BHA will come in many forms, such as toners, washes and cleansers. Choose which product would work best for you and your skin. Some skins are able to use BHA twice a day, or 2-3 times a week.
Due to the anti-bacterial and anti-inflammatory benefits of BHA breakouts will be treated quickly without causing aggravation for the skin.
Keep BHA away from the eyelids and lash lines.
If you suffer from rosacea you are able to use salicylic acid in your regime, it’s best to test it out first as some redness-prone skin can’t take much exfoliation.
BHA is able to penetrate further into the skin cutting through oils and clearing out pores, be it with a toner on a cotton disc or using your fingers with a face wash.

Something you will need to remember about using acids on your face is that you need to let them do all the hard work. You won’t need to rub the products in excessively to have the acids work.

Can You Mix AHAs and BHAs Together?

You can indeed use AHAs and BHAs together, you just need to find the right mixture and the time of day to use them in.

For example;

Morning: AHA, such as glycolic acid

Evening: BHA, salicylic acid

Try not to overload the skin by applying too many acids at one time. Once you have found the hydroxy acids that help your skin you are able to mix and match and treat any concerns you have. Keeping an alteration of acids will keep your face looking it’s best, healthiest state.

So, I hope that the idea of putting an acid on your skin is no longer as scary sounding as it did during the beginning of this guide. What you have to remember is to consider your age and skin type when choosing the right acid for you at the right level of concentrate. Alternating through the acids will also keep your skin looking flawless.

So as mentioned during the introduction, the number of people having a better understanding of ingredients and how they perform on your skin. Which is why we have decided to begin a series of dedicated guides exploring each acid in more detail, please do keep a lookout for more acid blog posts coming soon.