The Azelaic Acid 15 Intense Calming Serum by Anua is primarily praised for its effectiveness in reducing redness, calming the skin, and managing acne. However, specific mentions about strengthening the skin barrier are not prominent in the provided reviews. The reviews focus more on the serum's ability to reduce oiliness, redness, and blemishes, and its soothing effects on the skin.

While some users have mentioned that the serum helps in balancing the skin and reducing excess oil, which can indirectly support a healthier skin barrier, there is no direct evidence from the reviews that it specifically strengthens the skin barrier. It's important to note that azelaic acid is known for its anti-inflammatory and antibacterial properties, which can contribute to overall skin health, but the direct impact on the skin barrier might vary among individuals.