Is PHA (polyhydroxy acid) suitable for all skin types? How does it compare to AHAs and BHAs?
Polyhydroxy acids encompass gluconolactone and lactobionic acids. It has been reported in medical papers as early as 2004 to be effective and better tolerated by sensitive, aging skin.
PHAs works similarly to AHAs by causing the dead skin cells (keratinocytes) to shed at a higher rate, causing reduction in skin irregularities such as uneven pigmentation and texture. In addition, they fulfil the same function of allowing cosmeceutical ingredients such as hyaluronic acid and vitamin C serums to penetrate deeper into the skin.
Is there a possibility of suffering from a chemical burn using skincare products that contain PHA?
PHAs are not as commonly used as AHAs and BHAs, especially as chemical peels in dermatologists’ office setting mainly because the depth of penetration and effectiveness may be less. However, in skincare, the medical literature seems to report that it is a much gentler and moisturising type of chemical exfoliant than the other acids present in skincare, which translates into a much lower risk of skin irritation. In fact, PHAs are large molecules which function as humectants meaning that they trap water under the skin, prevent trans-epidermal water loss and have moisturising properties.
Is there one form of PHA that’s stronger than the others? eg. Lactobionic acid vs Gluconolactone
Clinical studies to date have grouped the use of gluconolactone and lactobionic acids under PHAs which differ from glycolic acids in the fact that they have a larger molecular structure, penetrate the dermis less and hence is less irritating in addition to having humectant (moisture trapping) properties. I am unaware of any head-to-head study which show whether one form of PHA is stronger than the other.
When should I use PHA? Should I use it in the toner, serum, moisturiser, or cleanser step?
The use of PHAs in skincare has been well-reported to have good exfoliating effects but without the irritation that glycolic (AHA) or salicylic acids (BHA) have. However, I generally do not put in chemical exfoliants in skincare because there is always a risk of skin becoming sensitive after being exposed to it on a daily basis.
There are some studies indicating that compared to glycolic acids which are incorporated in several brands of skincare, those which incorporate PHA are much more suited for people with sensitive, eczema skin. However, I would not prescribe that for my patients with eczema and rosacea in the first place due to the risk of irritation.
What should I be looking out for when I use PHAs?
I would say PHAs seem to be rather novel because it’s a term that hasn’t been used in the recent times but our knowledge of it has stemmed since the 1970s and clinical studies have been done with it since 2004. I think it’s important to prioritise, so the main concern really would be to ask yourself what your skin concern is. If it is anti-aging, then chemical exfoliation itself is not going to give you a miracle result.
Chemical exfoliation can be achieved with glycolic acids, BHAs and in this case PHAs may have the same function but with reduced skin irritation. However, chemical peels alone do not satisfactorily target all skin aging concerns, which lasers in combination with a good cosmeceutical regimen can achieve. It is important to caution that while all anti-aging treatments are aimed at increasing collagen production in the skin, an accredited dermatologist still needs to access the individuals’ problems and side effects before recommending combination treatment.
PHAs should be used in conjunction with cosmeceutical ingredients such as vitamin C as well as phyto which are plant-derived antioxidants that have been proven to fight free radical damage which is the key process in anti-aging. Nevertheless, PHAs are a beneficial form of chemical exfoliation and should be placed in the same category as the use of AHAs and BHAs in chemical peels.
One more thing to add, the clinical results in terms of the depth of skin penetration are likely to be less with PHAs. For patients with other forms of skin concerns, for example acne, they may still find that glycolic acid is much more effective in reducing oil control. If their concern is a medical condition like eczema and rosacea, then certainly I would recommend not using any form of chemical exfoliant at all and rather get treated by a dermatologist.
Exfoliation, or the removal of dead skin cells from the outermost layer of the skin, is an important and necessary part of any skincare routine. However, if the word ‘exfoliation’ conjures up to you the action of scrubbing your face with harsh granules, you may be doing more harm to your skin than good.
So what is the right exfoliation technique for your skin?
Benefits of Facial Exfoliation
We shed dead skin cells naturally as new skin cells slowly travel up from the deepest skin layers to the surface. On average, this process takes about 27 days. As we age, this cell turnover process slows down.
When we exfoliate, we remove the build-up of dead skin cells. Regular exfoliation can reveal younger, brighter skin with an even tone.
Types of Facial Exfoliation
Exfoliation can happen in two forms: physical and chemical.
Physical Facial Exfoliation:
Physical exfoliation relies on the rubbing of tiny granules or particles over the face to remove dead skin cells by physical force.
While this kind of exfoliation can leave you feeling refreshed, the technique can be too harsh for the skin, especially for individuals with acne-prone or sensitive skin. Physical exfoliation may even weaken the skin’s barrier function and leave your skin red or irritated.
For those of you without sensitive or acne-prone skin, physical exfoliation can still be an option. However, make sure to look out for exfoliating agents that are not too large.
Chemical Facial Exfoliation:
Chemical exfoliation relies on fruit enzymes and gentle acids to slough off dead skin. This mechanism is much gentler than physical exfoliation and more suitable for acne-prone and sensitive skin types.
Types of acids for chemical facial exfoliation
The two most well-known type of exfoliating acids is alpha hydroxy acids (AHA) and beta hydroxy acids (BHA).
AHAs: Alpha hydroxy acids work by causing skin cells to detach from the outermost layer of skin, making them easier to slough off. Once the dead skin cells are removed, new cells can rise to the surface.
Common AHAs used as chemical exfoliants are lactic, glycolic and mandelic acid.
Glycolic acid: Glycolic acid is the strongest AHA as it has the smallest AHA molecule. As such, it is able to penetrate deeper into the skin and can exfoliate at lower concentrations compared to other acids. However, if you are just beginning to try out chemical exfoliants, a different acid should be considered.
Lactic acid: Apart from exfoliating, lactic acid also moisturizes. Individuals with dry skin can consider lactic acid for this dual function.
Mandelic acid: With a larger molecular structure, mandelic acid is not able to penetrate deeply into the skin. This makes it a gentle AHA and safe to use, especially for people with sensitive skin.
BHAs: Beta hydroxyl acids (BHAs) differ from other AHAs as they are oil-soluble. This property allows them to penetrate deeper into our skin and pores.
BHAs exfoliate by softening the outermost layer of skin cells and dissolving unwanted skin debris. They also have anti-inflammatory and antibacterial properties, making them ideal for individuals with oily and acne-prone skin.
Chemical peels for facial exfoliation
Chemical peels are often done at a dermatologist’s office where the chemical agent used can be much more concentrated. Glycolic, lactic or salicylic acid is commonly used. A certified dermatologist is best able to identify the type of peel for your skin.
With regular use, these treatments exfoliate the surface skin and improve fine lines, wrinkles, skin discolouration and texture.
Chemical facial exfoliation at home
Most patients prefer to do chemical exfoliation on their own. However, this can cause skin sensitivity and redness for certain individuals over time without proper medical supervision.
Over facial exfoliation – what happens if you over exfoliate?
The benefits of chemical exfoliation may make it tempting to use AHAs and BHAs often. However, too much exfoliation can disrupt your skin barrier and cause the skin to become red and inflamed. Some encounter a form skin burns when dabbling into prescription type chemical exfoliators, whilst others may even develop eczema of the facial skin due to repeated unsupervised repeated exfoliations.
If you are a beginner to AHA and BHA, start slow with low doses. If you do not have sensitive skin, you may consider exfoliating every week with mild home use agents. Those with sensitive skin should not attempt self exfoliations. Discuss with your dermatologist to have your underlying skin condition resolved first before thinking how often you should get chemical peels or exfoliations.
Alpha hydroxy acids (AHA) are naturally-occurring compounds possessing unparalleled benefits to the skin and extensively used in a dermatologist’s office. Most AHAs are non-toxic and are often present in food and fruits, thus also known as fruit acids.
The types of AHA used commonly for cosmetic purposes are glycolic acid and lactic acid. Glycolic acid, found in sugar cane, has the smallest molecule of all the AHAs and is the most widely used acid in skincare. Lactic acid is present in sour milk and tomato juice and can be found in our bodies as a byproduct of metabolic processes.
Certain types of AHA have lipophilic (ability to dissolve in lipids/fats) side groups in its chemical structure such as mandelic acid and benzylic acid. Such acids are more soluble in lipids over the conventional water-soluble AHAs, thus are often used for oily and acne-prone skin.
Uses as a peeling agent
AHAs are commonly used in peeling procedures as a short intense exposure to the acid produces benefits to the skin. A chemical peel is the application of one or more chemical exfoliating agents to the skin, and by exerting a controlled epidermal injury, it allows regeneration of new epidermal and dermal tissue. Such treatments are often used to treat skin disorders and conditions for aesthetic improvement.
Using controlled higher concentrations of AHAs, application to the skin for short times can achieve substantial desquamation (skin peeling). This renewal of skin cells is useful in anti-ageing, reducing hyperpigmentation and improving radiance. It is important to have a chemical peel conducted by an accredited dermatologist, to prevent uneven peeling and dermal wounding.
In contrast to other peeling agents, such as phenol or salicylic acid, most of the AHAs are nutritive and physiologic.
Whilst most skin types can opt for an AHA chemical peel, it is imperative to first seek assessment by an accredited dermatologist who will cater the peel, such as the acid type, strength, frequency and duration, for variability of individual skin conditions. Performed properly by a trained dermatologist, risk of scarring from a chemical peel is drastically reduced. The level of expertise in administering peels ensures a good outcome.
Prior to the actual application of the chemical peel substance, the skin will need to be thoroughly cleansed to remove oil and debris before being rinsed and dried.
Treatment with Chemical Peel
The peeling agent (AHAs) will be applied on the skin using an applicator or a brush. The duration of allowing the peeling agent to be in contact with the skin varies according to the skin’s conditions as assessed by the dermatologist. With superficial peels, some sensation of heat and stinging may be experienced, before the peeling agent is neutralized (where applicable) and thoroughly cleansed off after the duration of contact recommended by the dermatologist.
The chemical peel treatment is completed at our clinic with application of a hydrating Amino Acid Masque to soothe and calm the skin post-peel. Additional post peel care requires the use of sunscreens and other photoprotective agents, due to sun sensitivity post-treatment. It should be noted that regular application of sunscreen is advocated as it can reduce sun damage and aggravating of skin conditions.
How does a chemical peel work?
For superficial peels, the acid causes breakdown and decreases cohesiveness of corneocytes, that are found at the outermost part of the epidermis. Desquamation occurs, allowing renewal from lower epidermal layers. By weakening and ‘ungluing’ the cells in the inner stratum layer, it leads to uniform exfoliation of the outermost stratum layers.
With a low PH, most acid peels need to be properly neutralized to prevent acidification of the skin. To avoid burning, AHA peels are neutralized with basic salts such as sodium bicarbonate or sodium hydroxide.
A chemical peel does not compromise the barrier structure or integrity of the skin, as the mechanism of action of AHAs on the skin is a more targeted action for epidermal skin renewal.
As a treatment that improves skin texture and counters the effects of ageing, chemical peels continue to be relied on for various skin conditions. It is also safe for the skin and human health in general, as extensively tried and tested by dermatologist’s. A range of AHA formulations and concentrations are available for the dermatologist to administer therapy according to the patient’s requirements.
Speak to your dermatologist today for a tailored experience.