Skin Type & Concerns

Combination, acne-prone skin with post-inflammatory hyperpigmentation, post-inflammatory erythema from healed acne, some textural irregularities, and hormonal acne. Located in Zone 6B, where the current climate has been warm and semi-humid.

Current Routine

□ AM : Water rinse → Non-AB hypochlorous acid spray → COSRX Propolis Toner → Skin1004 Madagascar Centella Ampoule → Cos de BAHA Azelaic Acid 10% Serum → Non-AB moisturizer → Asian sunscreen rotating among Kose Suncut UV Perfect Essence, Round Lab Birch Juice Moisturizing Sun Cream and Skin1004 Hyalu-Cica Water-Fit Sun Serum

□ PM : Heimish All Clean Cleansing Balm → Cleanser rotating among Soon Jung 5.5 Foaming Cleanser, COSRX Cica Creamy Foam Cleanser and COSRX Low pH Good Morning Cleanser → Non-AB hypochlorous acid spray → COSRX Propolis Toner → Skin1004 Madagascar Centella Ampoule → Cos de BAHA Azelaic Acid 10% Serum → Cos de BAHA TN Serum (5% Tranexamic Acid + 5% Niacinamide) → Non-AB moisturizer

Note on Azelaic Acid

While azelaic acid is not typically categorized as an active in the same way as retinoids or salicylic acid, I’ve incorporated this serum into both my morning and evening routines. I patch-tested beforehand and gradually introduced it 2–3 times a week to confirm skin compatibility.

Product Description

The serum has a clear, viscous, and slightly slippery texture with mild tackiness that settles nicely into the skin. There is no noticeable fragrance to me, though Incidecoder lists 2-3 fragrance components. It comes in a convenient dropper-style bottle.

Ingredients

Aloe Barbadensis Leaf Extract, Propylene Glycol, Azelaic Acid (10%), Polysorbate 20, 1,2-Hexanediol, Propanediol, Panthenol, Niacinamide, Sodium Hyaluronate, Camellia Sinensis Leaf Extract, Momordica Charantia Fruit Extract, Sambucus Nigra Flower Extract, Leontopodium Alpinum Extract.

Safety Information

Cos De BAHA products contain high concentrations of ingredients. Depending on the sensitivity of your skin, you can have experience with allergic reaction and face burning. Please test under the chin before use.

Experience

I’ve been using this product consistently since April 2024. Within the first few weeks, I began seeing noticeable improvements in redness, PIH, and the frequency/severity of acne flare-ups. It has since become a staple in my routine and I’ve gone through several bottles over the past year. In addition to facial use, I’ve applied it to areas of irritation or redness on my hands, chest, and back with good results. Most notably, it significantly reduced redness from broken capillaries on my hand in under 48 hours. 

Before

After

In Conclusion

This serum has worked effectively for my skin concerns and remains a permanent fixture in my routine. I will continue to repurchase for the foreseeable future.