The term“acid” might bring to mind harsh chemicals, but in skincare, these ingredients are some of the most effective means you can use for smoother, clearer, more even-toned skin. When used correctly, exfoliating acids can help fade discoloration, unclog pores, and boost overall brightness.
But here’s the thing: not all acids are created equal. This article explores AHAs, BHAs, and PHAs and how each active works on the skin Additionally, it helps you find the best match for your skincare routine.
AHA vs. BHA: What's the Difference?
AHAs, or alpha hydroxy acids, are water-based and stay on the surface of the skin. They’re excellent for lifting away dead skin cells, smoothing texture, and brightening tone. If you're looking for an easy way to incorporate them into your routine, a body wash with glycolic acid is a great place to start.
BHAs, or beta hydroxy acids, are oil-soluble. That gives them the ability to work deeper inside your pores, making them ideal for anyone dealing with blackheads, breakouts, or excess oil.
So how do you choose?
If your skin feels rough, dry, or looks dull, AHAs can help smooth and refresh it. If clogged pores, oily patches, or acne are your main concern, BHAs like Salicylic Acid are likely to be more effective.
Think of it like this: AHAs work on the surface; BHAs dive below. Your skin’s needs will point you in the right direction.
What Exactly Are AHAs?
AHAs gently break down the bonds that keep dead skin cells clinging to the surface. By clearing away that layer, your skin appears smoother, softer, and more radiant. They also encourage faster cell turnover, which is helpful for fading sun damage, softening fine lines, and refining texture.
Common AHAs & What They Do:
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Glycolic Acid – Made from sugarcane, this is the most and widely used AHA. Because of its small molecular size, Glycolic Acid penetrates easily, helping to brighten complexion, refine pores, and smooth skin. It's often the top pick for fading dark marks.
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Lactic Acid – A more gentle option, derived from milk. It exfoliates while also drawing in moisture, making it a great fit for dry or sensitive skin. It’s also thought to improve skin firmness over time.
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Mandelic Acid – A larger molecule means slower absorption, which makes this AHA less irritating. Mandelic Acid is great for sensitive skin and has antibacterial properties that can help manage mild acne.
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Malic Acid – Found in apples and other fruits, this acid offers lighter exfoliation and helps support hydration. It is often used alongside stronger acids to balance formulas.
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Tartaric Acid – Naturally found in grapes, Tartaric Acid plays more of a supporting role by helping to maintain pH levels in skincare products while adding a gentle exfoliating boost.
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Citric Acid – Sourced from citrus fruits, Citric Acid is often included for its antioxidant benefits and tone-evening effects. It usually works best in combination with other exfoliants.
What Are BHAs?
BHAs shine when it comes to deep cleansing. Because they’re oil-soluble, they can travel into your pores, dissolve built-up sebum, and prevent breakouts before they begin. They also have anti-inflammatory properties, which means they’re soothing for irritated or acne-prone skin.
People with oily or combination skin often benefit the most from BHAs. Over time, consistent use can help reduce the appearance of large pores, smooth out rough patches, and control shine.
The BHA You’ll See Most: Salicylic Acid
Salicylic acid is by far the most common BHA in skincare. It exfoliates from the inside out, breaking through oil and buildup to keep pores clear. It’s especially helpful for treating blackheads, hormonal breakouts, and even body acne. You’ll also find it in treatments for keratosis pilaris (the small bumps on the backs of arms or thighs).
What Are PHAs?
PHAs are often described as the “gentler cousins” of AHAs. They work in a similar way—removing dead skin from the surface—but because they have larger molecules, they don’t sink in as deeply. That makes them far less likely to cause irritation or stinging.
If your skin is very sensitive, prone to redness, or recovering from over-exfoliation, PHAs are a great place to start. They also hydrate while they exfoliate, and many offer antioxidant benefits to support your skin barrier.
A Few PHAs to Know:
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Gluconolactone – A mild exfoliant with moisturizing and calming effects. It’s often recommended after cosmetic procedures due to its gentleness.
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Lactobionic Acid – Offers light exfoliation while protecting the skin from free radical damage. It works well for dry or mature skin and helps improve elasticity over time.
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Galactose – A sugar-based PHA that supports moisture retention and helps improve tone and texture without causing stress to the skin.
How to Use Skincare Acids (Without Wrecking Your Skin)
Start Low and Slow
If you're new to acids, take it easy. Try using your chosen acid just 2–3 times per week at first. See how your skin responds, then slowly increase the frequency. Overdoing it can cause dryness, irritation, or even long-term damage to your skin barrier.
Don’t Combine Everything at Once
Stick to one acid product at a time when you're starting out. Mixing a BHA toner with an AHA mask, a PHA serum, or even an AHA BHA serum on the same day is a fast track to irritation. Instead, alternate—maybe AHA at night and PHA in the morning, or BHA every other evening depending on your needs.
Best Time to Use Acids
Most acids work best at night. Your skin does most of its repairing while you sleep, and you won’t have to worry about sun exposure. If you use any exfoliating acid in the morning, make sure you're following up with a good SPF — no exceptions.
Be Careful with Other Actives
Avoid layering exfoliating acids with strong retinoids or high concentrations of vitamin C unless a product is specifically formulated for it. Your skin can only handle so much at once, and pushing it too hard often backfires.
One Rule You Can’t Skip: Sunscreen
If you’re using acids—even gentle ones—sun protection is non-negotiable. Exfoliating makes your skin more vulnerable to sun damage, which can lead to pigmentation, inflammation, and faster aging.
Use an SPF of at least 30 every single day, even when it’s cloudy. Reapply every few hours if you’re outside. If you’re using Glycolic or Salicylic Acid body wash (like in a body wash), don’t forget to apply sunscreen there too
What Could Go Wrong?
Even when used properly, acids can cause side effects—especially early on.
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Redness, flaking, or stinging are common if you jump in too quickly or use too high a concentration.
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If your skin starts feeling tight or irritated, scale back and focus on moisturizers that contain Ceramides or fatty acids to help rebuild your barrier.
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Avoid acids on sunburned, broken, or inflamed skin. And if you're using a prescription treatment—like isotretinoin or topical retinoids—talk to a dermatologist before adding exfoliants.
For those who are pregnant or breastfeeding, it’s best to steer clear of high-strength salicylic acid unless your doctor says otherwise.
The Takeaway
Used right, acids can transform your skin. AHAs smooth and brighten, BHAs fight congestion, and PHAs hydrate gently.
The best one for you depends on your skin type and goals. Start slow, stay consistent, and don’t skip hydration or SPF.
From glycolic body washes to salicylic spot fixes, acids work—when matched well. For an all-in-one, an AHA BHA serum can smooth texture and clear pores.
FAQs
Can I use BHA and PHA at the same time?
You can, but ease into it. Try PHA in the morning and BHA at night to reduce the chance of irritation.
Will AHA or BHA fade a tan?
Over time, yes. These acids help speed up skin turnover, which can fade surface pigmentation. Just don’t skip sunscreen, or you’ll undo the benefits.
Is it safe to mix AHA/BHA with Vitamin C?
Not usually in the same routine. Use vitamin C in the morning and save acids for nighttime to avoid irritation and give each ingredient space to work.
Can I pair AHA/BHA with retinol?
Only if your skin is already used to both. Otherwise, use them on different days to avoid over-exfoliating.
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