What are AHA and BHA?

AHA stands for alpha-hydroxy acid - they are water-soluble acids derived from cane or other sugary fruits, used to exfoliate the skin. They are also known as Fruit Acids. Examples of AHAs are Glycolic, Lactic and Citric acids. 

AHAs are primarily used for:

- Uneven skin tone and enlarged pores
- Signs of ageing such as fine lines and surface wrinkles
- Mild hyperpigmentation like age spots, melasma, and scars
- AHAs are well suited for dry and mature skin due to their regenerative properties, as they gently peel the top layer of skin. However, AHAs are also beneficial to other skin types.

Because it is like any other acid, AHA can increase skin sensitivity, particularly to UV light, it is always recommended to use face sunscreen in conjunction with acids to prevent sun damage.

BHA stands for beta-hydroxy acid - they are oil-soluble acids that promote the growth of new skin cells by exfoliating its top layer. BHA can also be used on your scalp - it deeply penetrates into the hair follicles to dissolve the excess oil and sebum, an oily wax found in clogged pores. The most popular BHA is Salicylic acid.

BHAs are primarily used for:

- Calming sensitive skin
- Evening skin tone
- Unclogging pores
- Reducing rosacea-related redness
- Reducing acne-related inflammations

Given their anti-inflammatory nature, BHAs are best suited for those with a combination to oily or acne-prone skin, but they aren't exclusively used for any one skin type.

Being an oil-soluble acid, BHA penetrates your skin on a deeper level, which reduces excessive production of sebum that leads to acne.
BHA also has antibacterial and anti-inflammatory properties making it a great relief from the pain that might occur from an internal or persistent pimple, while reducing redness and swelling.

Due to skin cell regenerating properties, AHAs help stimulate collagen production, making them ideal for minimising fine lines and reducing visible sun damage. AHA is also very effective at gentle skin exfoliation as it peels the surface of your skin exposing more even skin tone and texture.

Whichever acid you decide to use, remember that they might increase your skin’s sensitivity, especially towards sunlight. This is why it is advised to gradually work up to daily use and always use sunscreen to avoid skin irritation.

AHAs and BHAs have numerous skin benefits on their own; however, when these acids are carefully combined, your skin can benefit even more.
The safe way to combine AHAs and BHAs is by using one product that contains both acids - the formula would contain a balanced percentage  with a low risk of over-exfoliation or irritation.

If you are using at-home chemical peels that are two separate products, one with AHA and another with BHA, try not to layer AHAs and BHAs on top of one another as they are both exfoliators, so using both at the same time can cause irritation.

Instead, you can alternate the days in which you are using them or try using one in the morning skincare routine and the other one in the evening.

The safe way to combine AHAs and BHAs is by using one product that contains both acids - the formula would contain a balanced percentage  with a low risk of over-exfoliation or irritation.

Products with acids such as serums should be applied before moisturiser - let it sit for 15 minutes to work its magic and then follow up with the rest of your skincare routine. Be sure to start slowly when using either type of acid, as too much of it can cause skin irritation. Start with twice per week, check how your skin is reacting, then introduce daily use. 

If you're using a serum following the AHA and BHA, apply the preferred acid first, then wait a few minutes before applying the serum. This will allow the acids to penetrate the skin and get to work exfoliating it and enable deeper penetration of the selected serum.

AHAs and BHAs can make your skin more sensitive to the sun, so it's important to protect your skin from UV radiation by using sunscreen, even if you’re only using the exfoliant in the evening!

Many products combine both AHAs and BHAs in one formula, so you can get the benefits of both acids in a single product.