I first sampled before deciding to buy it and it's the only way I would've known how awesome this product is. It works well into my acne-treated regiment and I use it almost every day as a serum in the day and night. It's pretty neutral and didn't cause any inflammation or dryness when it was being used with my other skincare products. I have oily and mild acne-prone skin -that's only increased onto my cheeks and jawline since wearing a mask more- and I still follow it with a moisturizer and even facial oil sometimes (on the days I'm home and won't be out and about wearing a mask) and there's been no heaviness from the combination. It even works well with my Differin at night. The smell is pleasant and the packaging is even well-designed. As of right now, 4% niacinamide is the standard amount but I'd probably look for a product with more in the future for possibly better results. However, considering the ingredients are mostly naturally impactful, it's pretty good.