Chemical exfoliants have become a staple of any modern skincare routine. The two best-known are glycolic acid and salicylic acid — but they do very different things. One acid works mainly on the skin's surface, the other deep inside the pore. In this guide we explain the difference and help you choose which acid, or which combination, best suits your skin.
What is glycolic acid?
Glycolic acid is an alpha hydroxy acid (AHA) and the smallest AHA molecule there is. Because it is water-soluble and small, it works mainly on the skin's surface: it loosens the bonds between dead skin cells so they shed more easily. The result is a smoother texture, a more even and radiant complexion and less visible fine lines. That makes glycolic acid a logical choice for dull, dry, uneven or ageing skin.
What is salicylic acid?
Salicylic acid is a beta hydroxy acid (BHA) and, by contrast, oil-soluble. That allows it to cut through sebum and work inside the pore. It helps loosen congestion, regulates excess oil and tackles blackheads and impurities. Salicylic acid is also soothing. It is the go-to choice for oily, congested or blemish-prone skin with clogged or visible pores.
Glycolic vs salicylic acid: the key differences
| Glycolic acid (AHA) | Salicylic acid (BHA) | |
|---|---|---|
| Solubility | Water-soluble | Oil-soluble |
| Works mainly | On the surface | Inside the pore |
| Best for | Texture, dullness, fine lines | Impurities, sebum, clogged pores |
| Ideal skin type | Dry, normal, ageing | Oily, combination, congested |
Which acid suits your skin?
- Dull, dry or ageing skin → choose glycolic acid for smoothness and glow.
- Oily, congested skin with clogged pores → choose salicylic acid to clear the pore.
- Combination or blemish-prone skin → a multi-acid approach that combines the two often works best.
How Marini SkinSolutions approaches it
Within Marini SkinSolutions you will find both routes reflected in two product lines.
Bioglycolic® — glycolic acid. The Bioglycolic line is built entirely around glycolic acid. The Bioglycolic® Face Cleanser cleanses and exfoliates in one step, the Oily Skin Cleansing Gel is a more robust option for oily skin, and the Bioglycolic® Resurfacing Body Scrub brings the same smoothness to the body.
Bioclear® — glycolic and salicylic acid. Want the best of both? The Bioclear formulas combine glycolic acid, salicylic acid and azelaic acid in a single product. The lightweight Bioclear® Face Lotion and the richer Bioclear® Face Cream work on texture, clogged pores, redness and post-acne marks all at once — ideal for congested or uneven skin.
Can you combine glycolic and salicylic acid?
Yes, but with care. Using both acids at the same time and too often can overload the skin barrier, leading to irritation, redness or a tight feeling. Two safe routes: build up gradually (start a few times a week) or choose a ready-made multi-acid formula such as Bioclear, in which the concentrations are balanced with one another. Also using retinol? Don't combine it in the same routine when you are just starting out with acids.
Protect your skin during the day
Acids make the skin more sensitive to the sun. So always use an SPF during the day: it helps prevent irritation and protects the results of your exfoliation.
Frequently asked questions
What is the difference between glycolic acid and salicylic acid?
Glycolic acid (AHA) is water-soluble and works on the skin's surface for texture and glow. Salicylic acid (BHA) is oil-soluble and works inside the pore on impurities and sebum.
Which acid is better for oily, congested skin?
Salicylic acid, because it penetrates into the pore. A multi-acid formula with both glycolic and salicylic acid can work even more completely.
Which acid should I choose for dry or ageing skin?
Glycolic acid, for a smoother texture, a more even complexion and less visible fine lines.
Can I use glycolic and salicylic acid together?
Yes, but build up gradually or choose a balanced multi-acid formula to avoid over-exfoliation.
Do I need to use SPF when using acids?
Yes. Acids make the skin more sensitive to the sun, so an SPF during the day is essential.
