While Retinol is the optimal active ingredient for rejuvenation, AHA and BHA are perfect stepping stones for a specialized treatment regimen. However, confusing these two types of acids not only makes the skincare routine less effective but can also lead to irritation and sensitivity.

Let oh!oh! help you compare and decipher the detailed differences, from basic to in-depth, to find the true active ingredient for your skin.

1. Absorption Mechanism

The biggest difference between AHA and BHA lies in their solubility, which determines how they penetrate the skin:

Absorption Mechanism (AHA vs BHA comparison)

👉 AHA (Alpha Hydroxy Acid): This group of acids is water-soluble. They include familiar key ingredients like Glycolic Acid and Lactic Acid. Being water-soluble, AHAs primarily work on the surface of the epidermis.

👉 BHA (Beta Hydroxy Acid): The most prominent representative is Salicylic Acid. Unlike AHAs, BHAs are oil-soluble. This characteristic allows BHAs to penetrate through the sebum layer, delving deep into pores to cleanse from within.

2. Mechanism of Action from Surface to Deep within Pores

To understand more deeply, we need to look at how they exfoliate dead skin cells:

🔹 AHA - Surface Resurfacing Active

AHAs work by breaking down the cellular bonds between old, dead skin cells on the skin's surface.

Mechanism: When these bonds loosen, the rough, dead skin layer peels off, revealing smoother, brighter new skin underneath.

Outstanding feature: AHAs have the ability to hydrate the skin, preventing dryness and instead making it plump and smooth, while also helping to reduce fine lines.

🔹 BHA - Pore Refining Active

BHAs not only remove dead skin cells from the surface but also have the ability to exfoliate deep within the pores.

BHA's mechanism of action (AHA vs BHA comparison)

Mechanism: BHAs dissolve excess oil and trapped dirt - the main causes of acne. Notably, BHAs have natural anti-inflammatory and antibacterial properties, helping to soothe red, swollen acne spots.

Outstanding feature: BHAs can control oil production, making pores appear smaller, smoother, and less oily.

3. OVERALL COMPARISON TABLE

AHA and BHA comparison table

4. When should both AHA and BHA be combined?

Many people wonder if they can use both AHA and BHA. The answer is YES, if you have oily combination skin and are experiencing signs of aging.

This combination creates a synergistic effect: BHA deeply cleanses inside the pores, while AHA addresses smoothness and pigmentation on the skin's surface. However, always apply the rule of alternating AHA and BHA to avoid overloading the skin's protective barrier.

5. Expert Guide to Using AHA and BHA

For active ingredients to be maximally effective without causing adverse reactions, remember the following notes:

👉 Starting concentration: Begin with a low concentration to allow the skin to adapt.

Many high-concentration BHA products today can easily cause redness or flaking if the skin doesn't have time to adjust. That's why the modern skincare trend is shifting towards acid-containing toners.

BHA specifically for beginners - oh!oh! BHA 2% toner: b (AHA vs BHA comparison)

A typical example is oh!oh! BHA 2% Toner: b - a product highly praised by the scientific skincare community for its intelligent concentration complex (1.5% Salicylic Acid & 0.5% Betaine Salicylate). This combination helps to release accumulated sebum in a controlled, effective manner while ensuring the skin's protective barrier is not overly compromised.

👉 Appropriate pH: Both work best at a pH of 3.0 - 4.0. Do not use immediately after highly alkaline skincare products.

👉 Hydration and recovery: Every treatment regimen needs HA and Ceramides to soothe and restore the lipid barrier.

👉 Use sunscreen: Acids thin the stratum corneum, making it more sensitive to UV rays. So, don't forget to protect your skin with broad-spectrum sunscreen.

Whether you choose to use AHA or BHA, consistency and understanding your skin are always key factors. Let these active ingredients help you feel more confident with a radiant complexion every day.