When used correctly, exfoliating acids are very effective in improving skin texture and radiance and preventing acne.
If you have a dull complexion, clogged pores, wrinkles, or blemishes, exfoliation can be your best beauty ally. But with AHAs, BHAs, PHAs, glycolic acid, salicylic acid, and all the other acids available in cosmetics, it's easy to feel lost. Which acid should you choose for your skin type? How often should you use it? How can you avoid mistakes that can damage your skin?
This comprehensive guide explains everything about exfoliating acids: how they actually work, their key differences, how to choose them according to your skin type and goals, how to use them correctly in your routine, and most importantly, the mistakes to absolutely avoid. Whether you're a complete beginner or already a skincare expert, you'll discover how to transform your skin from the inside out thanks to the science of exfoliating acids. When used correctly, exfoliating acids are incredibly effective at improving skin texture and radiance, preventing acne, reducing wrinkles, and refining pores. Get ready to reveal smoother, brighter, and more radiant skin!
WHAT IS EXFOLIATION AND WHY IS IT ESSENTIAL?
Exfoliation involves removing the dead skin cells that accumulate on the surface of the skin to reveal the fresh, new cells underneath. This is key to achieving a brighter, fresher, and flawless complexion, and also allows subsequent skincare products (serums, creams) to penetrate more effectively.
Natural Cell Renewal
Every day, your skin naturally renews itself: surface cells die while new cells replace them from the deeper layers. In adulthood, this complete cell renewal cycle takes approximately 30 days. Your cells gradually move from the dermis to the epidermis where they die and are shed.
The problem: With age, this process slows down considerably. By age 40, cell renewal can take up to 45-60 days. The result: dead cells accumulate on the surface, giving a dull complexion, a "thick" appearance to the skin, clogged pores that promote blemishes, and an uneven texture.
The Benefits of Exfoliation
Regular and well-executed exfoliation offers spectacular results:
- Bright and radiant complexion: By removing the layer of dull dead cells, you reveal the fresh skin underneath which reflects light better.
- Refined texture: The skin becomes visibly smoother to the touch, as if delicately "sanded".
- Unclogged and tightened pores: Exfoliation deeply cleanses pores clogged with sebum and dead cells, preventing blackheads and pimples.
- Better penetration of skincare products: On exfoliated skin, your serums and creams penetrate up to 3 times better, maximizing their effectiveness.
- Collagen stimulation: Exfoliating acids send a signal to fibroblasts to produce more collagen, improving firmness and elasticity.
- Reduction of wrinkles and fine lines: By stimulating cell renewal and collagen production, exfoliation reduces the signs of aging.
- Evens out skin tone: Reduces pigment spots, acne scars and hyperpigmentation.
- More even makeup: On perfectly smooth skin, foundation applies flawlessly without a "crocodile skin" effect.
THE DIFFERENCE BETWEEN THE DIFFERENT ACIDS AHA, BHA AND PHA
AHAs (Alpha Hydroxy Acids)
AHAs are water-soluble and work primarily by exfoliating the skin's surface, brightening the complexion and improving its texture. They also stimulate hydration and promote collagen production.
Choose an AHA if you want to treat fine lines, even out your skin tone and texture, or if you have oily skin.
THE DIFFERENT AHAs
Glycolic Acid
Glycolic acid is the acid that penetrates the deepest into the skin, making it the most effective because it has the smallest molecule of all acids. It can dissolve excess oil and dead skin cells, revealing smoother, brighter, and younger-looking skin.
It regenerates collagen and reduces the appearance of wrinkles and fine lines. It diminishes blemishes and scars. It is recommended for preventing acne and blackheads by unclogging pores. It is not recommended for sensitive skin but can be used by pregnant women.
LACTIC ACID
Lactic acid is the second smallest molecule after glycolic acid. It's a good alternative for sensitive skin because it provides the same results as glycolic acid while being very gentle and well-tolerated by all skin types. This acid, derived from sugar or fermented milk, improves skin texture and radiance. In addition, it's a moisturizing agent that attracts water.
Our Lactic Acid treatments:
• Acid (Wash) - NATOR AGENT
• Holi (Bright) Resurface Glass Face Mask - AGENT NATEUR
• Flower Acid Algae Serum - MARA
FRUIT ACIDS
Fruit acids are the gentlest. These include citric acid and malic acid. Their larger molecules act on the upper layer of the skin. They are often combined with glycolic or lactic acids to enhance their effectiveness.
Our Fruit Acid treatments:
• Synergy[4] 4-in-1 Probiotic Powder Mask + Fruit Acids - ODACITE
• Algae and Enzyme Cleansing Oil - MARA
BHA ACIDS (Salicylic Acid)
Salicylic acid is one of the most popular ingredients for treating acne. It penetrates and dissolves the sebum that clogs pores while exfoliating dead skin cells. Even better, it works without irritating already inflamed skin because it has anti-inflammatory properties. If you've never used an acid before, salicylic acid is a perfect place to start.
Originally, salicylic acid, or BHA, was extracted from willow bark, hence its name, but it is also found in many fruits and vegetables such as almonds, tomatoes, apricots, and grapes. It is primarily known for its analgesic and anti-inflammatory properties, but it also has numerous other benefits for the skin. It is one of the most popular ingredients for treating acne, blackheads, and enlarged pores.
The benefits of salicylic acid:
REDUCES IMPERFECTIONS AND PREVENTS THEIR APPEARANCE
Salicylic acid gently exfoliates the skin by penetrating pores and dissolving sebum, impurities, and bacteria that clog them, while also removing dead skin cells. By cleansing pores, it helps prevent blemishes.
REDUCES THE APPEARANCE OF PIGMENTATION SPOTS
Sun exposure can lead to the appearance of pigmentation spots. Using skincare products containing BHA helps remove dead skin cells and brighten the complexion thanks to its exfoliating properties. This stimulates cell renewal.
REDUCES INFLAMMATION
Salicylic acid also possesses anti-inflammatory and antimicrobial properties that may be beneficial in reducing inflammation, redness, and itching resulting from sun exposure.
KEEPS SKIN RADIANT AND NON-OILY
BHAs help improve the texture and radiance of skin, which tends to look duller during the summer. It also tends to get oily more easily, which is why it's helpful to use a cleanser or toner to counteract excess sebum production and minimize pores.
A very important point is that salicylic acid does not increase the skin's sensitivity to the sun, so it can be applied morning and evening to deeply cleanse pores. However, we recommend that you always follow its application with sunscreen.
Our Salicylic Acid treatments:
• Renewing Polish - Exfoliating Scrub - GRESSA SKIN
• Turmeric Blue Aura Micellar Water + Holy Basil - ODACITÉ
• Hydra-purifying Treatment Mist with Mint and Green Tea - ODACITÉ
• Hydra Daily Exfoliating Scrub with White Tea + Rooibos and Jojoba Beads - ODACITÉ
PHA acids (Polyhydroxy acids)
PHAs represent the new generation of exfoliating acids, developed specifically for skin that does not tolerate traditional AHAs or BHAs. Chemically, they are similar to AHAs (also water-soluble), but their molecular structure is radically different.
The major difference: PHAs have much larger molecules than classic AHAs. While glycolic acid (AHA) measures 76 daltons, a PHA like gluconolactone reaches 178 daltons. This impressive size completely changes their behavior on the skin.
As a result, PHAs penetrate the epidermis much more slowly and superficially. They remain primarily on the skin's surface, where they provide ultra-gentle exfoliation without ever reaching the deeper layers that could become irritated. It's like having exfoliating power without the harshness.
Another distinctive feature: PHAs contain multiple hydroxyl groups in their chemical structure, which gives them unique moisturizing and antioxidant properties that other acids do not possess to the same degree.
• Renewing Polish - Exfoliating Scrub - GRESSA SKIN
INSTRUCTIONS FOR USE: HOW TO USE ACIDS CORRECTLY
Frequency of Use
BEGINNER:
Weeks 1-2: 1x/week
Weeks 3-4: 2x/week
Month 2: 3x/week if well tolerated
SKIN USED TO:
3x/week or daily while cleaning
GOLDEN RULE: Increase gradually. It's better to underdose than overdose.
Application Time
Always in the evening
In the morning, the skin has just finished its nighttime regeneration work: it is at this time that it naturally repairs and strengthens its skin barrier, this thin protective layer that retains moisture and blocks external aggressions.
Applying acids upon waking weakens this newly rebuilt barrier. As a result, the skin becomes more vulnerable to dehydration, bacteria, and blemishes. Even worse, when exposed to the sun, it can react more intensely to UV rays and lose its balance.
Reserve the acids for the evening. This is when the skin is most receptive to cell renewal and can fully benefit from their effects, without interfering with its natural defense mechanisms.
And also, in the evening, we don't put on makeup afterwards, which leaves the skin completely free to breathe and regenerate without interference.
Order in the Routine
COMPLETE EVENING ROUTINE:
1. DOUBLE CLEANSING: Makeup Removing Oil + Cleanser
→ Removes makeup, sebum, impurities
2. TONIC
→ Rebalances pH after cleansing. Maximizes the absorption of subsequent skincare products.
3. EXFOLIATING ACID (AHA/BHA/PHA)
→ ON CLEAN, DRY SKIN (important!)
→ Apply to the entire face (avoid the eye area)
→ WAIT 1-2 MINUTES before the next step to allow the product to fully penetrate
4. Targeted serum (hydration, anti-aging...)
→ Hyaluronic acid, niacinamide, peptides
5. EYE CONTOUR
6. FACIAL OIL
Applying an oil as the last step in your routine helps seal in moisture and enhance the effectiveness of the skincare products applied underneath. Thanks to its slightly occlusive effect, the oil forms a protective film that prevents water from evaporating and keeps the active ingredients where they need to work: deep within the skin.
The right associations
Skin cycling is a smart nighttime method that alternates the application of powerful active ingredients (acids, retinol) with regenerative rest phases for the skin.
Instead of accumulating numerous different treatments that can compromise the skin barrier, the technique relies on a three-night cycle:
Day 1: exfoliation with exfoliating acids, to rid the skin of dead cells and smooth the skin texture.
Day 2: application of a retinol-based treatment to stimulate cell renewal and collagen production.
Day 3: recovery phase, where we prioritize repairing and hydrating treatments to allow the skin barrier to regenerate.
This method optimizes the effectiveness of each treatment without weakening the skin, while respecting its natural regeneration rhythm.
Skin cycling puts what the skin truly needs back at the center: rhythm, breathing, and respect. By following this rhythm, you achieve healthier, brighter, stronger, and more tolerant skin—skin that progresses without ever being damaged.