AHAs in Skincare: What They Are, What They Do, + How to Use Them
Alpha hydroxy acids (AHAs) are a category of chemical exfoliants used to remove dead skin cells, brighten the complexion, and improve skin texture with consistent use.
AHA Benefits Overview
- AHAs gently exfoliate the skin’s surface, helping to smooth skin texture and boost brightness.
- Consistent use of AHAs improves hydration, fades hyperpigmentation + reduces the appearance of fine lines.
- Beginners should start with a gentler formula (under 10%), and gradually increase frequency as tolerated.
- Daily sunscreen use is essential — AHAs can increase sun sensitivity!
- AHAs are safe for most skin types, but those with sensitive, damaged, or highly reactive skin should exercise caution and patch test first.
What Are AHAs?
Alpha hydroxy acids (AHAs) are water-soluble acids naturally derived from fruits, milk, and sugarcane. In skincare, AHAs act as chemical exfoliants, breaking down the bond between dead skin cells. This process accelerates skin cell turnover and reveals smoother, brighter skin underneath.
AHAs offer a gentler alternative to physical exfoliants, making them more suitable for sensitive or dry skin. Common AHAs include:
- Glycolic Acid: Sourced from sugarcane, glycolic acid has the smallest molecular size among AHAs. Because of this small particle size, glycolic acid can penetrate deep into the skin, smoothing fine lines + improving texture. Best suited for normal to oily skin types.
- Lactic Acid: Derived from fermented milk or sugar, lactic acid is ideal for dry or sensitive skin. Its larger molecular structure results in gentler exfoliation that hydrates the skin with natural humectant properties.
- Mandelic Acid: Extracted from bitter almonds, mandelic acid has one of the largest molecular sizes among AHAs, which allows it to exfoliate the skin more slowly and gently. Mandelic acid is well-suited for very sensitive or acne-prone skin.
- Citric Acid: Citric acid is naturally found in citrus fruits and provides mild exfoliation and antioxidant benefits. It is typically used to brighten dull skin and even out skin tone, and works best for those concerned about radiance + discoloration.
How Alpha Hydroxy Acids Work on the Skin
Alpha hydroxy acids (AHAs) exfoliate the skin by breaking down the bonds that hold dead skin cells together on the surface. These bonds (known as desmosomes!) keep the outer layer of skin (stratum corneum) intact. By dissolving them, AHAs promote cellular turnover, allowing fresher, healthier skin to appear quicker.
Unlike physical exfoliants, which remove dead cells through friction, AHAs function chemically — reducing the risk of micro-tears and irritation, making AHAs a gentler alternative for those with dull, uneven, or sensitive skin.
Top Skin Benefits of Alpha Hydroxy Acids (AHAs)
When incorporated regularly into a skincare routine, alpha hydroxy acids (AHAs) offer visible and clinically-backed skin benefits.
- Brighter, More Radiant Complexion
AHAs immediately improve skin luminosity by removing the outermost layer of dead skin cells. This exfoliation reveals fresher skin beneath + contributes to a healthy, natural glow over time.
- Smoother Skin Texture
Consistent use of AHAs helps soften rough patches, reduce flakiness, and refine the skin’s surface. This smoothing effect can also minimize the appearance of enlarged pores, making makeup application easier.
- Increased Skin Hydration
Certain AHAs like lactic acid function as humectants — ingredients that draw moisture into the skin. Humectants help maintain hydration levels, making the skin appear more plump, soft, and supple.
- Reduction of Dark Spots and Hyperpigmentation
AHAs promote accelerated skin cell renewal, gradually fading sun spots, post-inflammatory hyperpigmentation (PIH), and uneven skin tone over several weeks — leading to a clearer, more uniform complexion.
- Fade Fine Lines and Wrinkles
By encouraging collagen production and accelerating the shedding of damaged surface cells, AHAs can reduce the appearance of fine lines and early wrinkles — making them a great option for those concerned with signs of aging.
Understanding Types of AHA Skincare Products
AHAs come in several formats, each designed to deliver exfoliation at different strengths and frequencies. Choosing the right one depends on your skin type, tolerance for exfoliants, and skin goals.
- Toners
AHA toners are lightweight and gentle — offering mild, daily exfoliation. They’re best for sensitive skin or beginners looking to maintain a glow without irritation. - Serums
More concentrated and targeted, AHA Serums improve texture, dullness, and uneven tone. They are ideal for intermediate users looking for visible results. - Peels and Masks
These are stronger rinse-off treatments used weekly for deeper exfoliation. Peels and masks are best for congested or dull skin, but not recommended for sensitive or reactive types.
Each format serves a different purpose. If you’re new to acids, start with a toner or low-strength serum and increase intensity gradually, based on how your skin responds.
Possible Side Effects of Alpha Hydroxy Acids (AHAs)
While alpha hydroxy acids (AHAs) are safe and well-tolerated for most people, some may experience mild side effects during the initial weeks of use or when applying higher concentrations. These effects are generally temporary and manageable with the proper precautions.
Common Side Effects of AHAs
- Mild Redness or Tingling
A slight tingling or warming sensation is common when first using AHAs. This is a normal response to increased skin activity and typically fades as your skin builds tolerance. - Temporary Dryness or Flaking
As your skin adjusts to AHAs, you might notice a slight dryness or flaking — that’s totally normal! AHAs can temporarily disrupt the skin barrier, but a deeply hydrating moisturizer (like our fan-favorite Honey Halo ceramide face moisturizer) can help bring things back into balance. - Increased Sun Sensitivity
Exfoliated skin is more vulnerable to UV damage. Without sunscreen, you’re leaving your skin exposed to sunburn and dark spots. Daily SPF is essential when using AHAs — but truthfully, it should already be a non-negotiable step in your routine.
Who Should Avoid Alpha Hydroxy Acids (AHAs)?
You should avoid AHAs or use caution if you:
- Have highly sensitive or reactive skin
- Are experiencing sunburn, inflammation, or open wounds
- Use prescription retinoids or acne medications
- Have known allergies to AHA ingredients
How to Use AHAs Safely and Effectively (with Farmacy’s Picks)
AHAs are powerful exfoliants, but it’s best to ease them into your routine to avoid irritation, dryness, or extra sensitivity. Nighttime is usually the sweet spot, since it limits sun exposure and works with your skin’s natural repair cycle.
Here’s how to use AHAs the right way, plus the ideal step-by-step order and our top product picks to help you get started:
AHA Best Practices
- Start with a low concentration (5–10%) and use 2–3 times per week
- Always patch test before applying to your whole face
- Avoid layering with other potent actives (like retinoids, vitamin C, or benzoyl peroxide) in the beginning
- Follow with a moisturizer to help support your skin barrier
- Use broad-spectrum SPF every day (even when it’s cloudy!)
AHA Skincare Routine (Evening Recommended)
1. Cleanse
Gently wash away makeup + impurities with a non-stripping cleanser.
Try: Farmacy Green Clean Cleansing Balm
2. Apply AHA
Smooth on your AHA toner, serum, or mask, avoiding the eye area and any broken skin.
Try: Farmacy Honey Glow 17% AHA + BHA Resurfacing Acid Serum
3. Moisturize
Follow with a hydrating cream to replenish moisture and protect your skin barrier.
Try: Farmacy Honey Halo Ultra-Hydrating Ceramide Moisturizer
4. SPF (in the AM)
If you apply AHAs in the morning, sunscreen is non-negotiable.
Try: Farmacy Green Defense Mineral SPF 30
Tip: Most skin types tolerate AHAs better at night, especially when you're just starting out.
AHA vs. BHA
Both AHAs and BHAs are both chemical exfoliants, but they work differently and target different skin concerns.
- AHAs (Alpha Hydroxy Acids) exfoliate the skin's surface, making them ideal for dullness, uneven texture, and visible signs of aging.
- BHAs (Beta Hydroxy Acids) like salicylic acid go deeper, helping clear pores and reduce oil, making them better suited for oily or acne-prone skin.
Some skincare products combine both acids to address multiple concerns at once. For example, Farmacy's Honey Glow Serum blends AHAs and BHA to create a smooth texture while helping clear pores.
The Glow-Up Starts Here
When used with care, AHAs can reveal brighter, smoother skin. Start slow, reach for skin-loving formulas made with clean, farm-sourced ingredients, keep your moisture barrier happy, and never skip SPF.
Ready to try AHAs? Explore Farmacy’s glow-boosting skincare today and find what works best for your routine.
AHA FAQs
AHAs exfoliate the skin by dissolving the bonds between dead skin cells, revealing a brighter, smoother, and more even-looking complexion.
Yes, glycolic acid is a type of AHA. Its small molecular size allows it to exfoliate the skin’s surface to improve texture and tone.
No, azelaic acid is not an AHA. It is a dicarboxylic acid with anti-inflammatory and skin-brightening properties — often used for acne and rosacea.
Low concentrations of AHAs, like glycolic or lactic acid, are generally considered safe during pregnancy — but it’s always best to check with your healthcare provider first.
Using AHAs and retinol at the same time can lead to irritation. Try alternating them on different nights or using one in the morning and one at night if your skin can tolerate it.
No, salicylic acid is a BHA (beta-hydroxy acid). BHAs penetrate pores to reduce oil and acne, making them ideal for oily or breakout-prone skin.
AHAs should be used two to three times per week. If your skin adjusts well, you can gradually increase frequency while monitoring for signs of irritation.
