What are Hydroxy Acids?

Hydroxy Acids are chemical exfoliants commonly found in skin care that boost cellular renewal and are therefore very effective in preventing and improving the signs of skin aging. There are 3 main types of Hydroxy Acids, each suitable for treating specific skin concerns and skin types:

  • Alpha Hydroxy Acids (AHA’s)
  • Beta-Hydroxy Acids (BHA’s)
  • Poly-Hydroxy Acids (PHA’s)

Alpha-Hydroxy Acids

AHA’s are the most common type found in skin care and skin peeling treatments and are generally suitable for all skin types at lower concentrations. AHA’s are water soluble molecules and each have their own strengths, but they all work by removing the top layers of dead skin cells and improving cell turnover. Popular Alpha-Hydroxy Acids include:

  • Glycolic Acid – Derived from sugar cane, these small molecules penetrate deep into the skin and are great to improve skin texture, discoloration, fine lines, wrinkles and skin density.
  • Lactic Acid – A milder acid, that is more tolerable and great for dehydrated and dry skin as it helps bind moisture to the skin.
  • Citric Acid – Boasts additional antioxidant benefits and is effective in unifying skin tone and smoothing the skin.
  • Mandelic Acid – A milder acid often combined with other AHA’s.  Great for treating acne and improving skin texture.

These acids can be quite potent, so when introducing your skin to AHA’s do so gradually and start with a lower percentage of between 5 – 10% acid concentration within each product. Depending on the concentration of your product, you probably want to limit your usage to once or twice a week initially.

AHA’s should not be layered with Retinoids and they can cause increased sun sensitivity, so it is paramount to apply a sunblock during the day.


Beta-Hydroxy Acids

BHA’s are oil soluble and ideal for oily, acne prone and combination skin. This type of acid is brilliant at flushing out blocked pores, balancing oil production, has anti-inflammatory properties and anti-ageing benefits.

  • Salicylic Acid –  is the primary BHA and derived from the bark of willow trees.

BHA’s can cause skin to be more sun sensitive and like AHA’s should not be layered with retinoids. A great addition though, is using products with Hyaluronic Acid (HA). Unlike hydroxy acids, HA is not an exfoliator but an hydrator, so they work very well together.

Salicylic Acid is not considered 100% safe during pregnancy.  A low concentration in topical creams or cleansers shouldn’t be a problem, but we don’t recommend having Salicylic peels. Rather use an AHA over this period.


Poly-Hydroxy Acids

PHA’s  are unique in that they help strengthen the skin’s barrier function and fight the signs of aging without the irritation of the classic AHA. Poly-Hydroxy Acids have a larger molecule and work closer to the skin’s surface.

They can also be safely used with a variety of other ingredients such as retinoids and hydroquinone and can be used both morning and night. Common PHA’s include:

  • Gluconolactone
  • Galactose
  • Lactobionic acid

PHA’s are great for sensitive and more reactive skin showing signs of aging. They are also safe to use during pregnancy and don’t cause increased sun sensitivity. Though, of course,  we do always recommend using a sunblock daily.