Go Deep 8% Mandelic Acid Serum Concentrate.

"This is the Go Deep 8% Mandelic Acid Serum Concentrate, and this is the hero product. Mandelic acid is a really smart choice for an acne-focused line, and it's not an ingredient a lot of other lines have focused on. It's an alpha hydroxy acid with a larger molecule size than something like glycolic acid, so it penetrates more slowly, which makes it significantly more gentle, especially for sensitive or darker skin tones, where other AHAs can cause irritation or even post-inflammatory hyperpigmentation. It exfoliates, helps with texture, fades post-acne marks, and can support collagen production to a small degree over time with consistent use. At 8% I think this is a meaningful concentration, not just a token amount, and the supporting ingredients, including licorice root extract, arginine, squalane, centella asiatica, and synactin AC, are pretty solid. It's a PM only product, which is correct since alpha hydroxy acids can increase photosensitivity, so you need SPF in the morning, and if you're new to exfoliating acids you might want to start with it two or three nights a week. It's the most expensive product in the lineup at $39."

"I think the formula is great and if you are comfortable paying that price point for a serum, go for it. But yeah, I feel like this one is just a little bit too expensive for what you're getting. Great formula, love the ingredients, but nothing on the ingredient list that would make me be like, 'Oh my gosh, this is totally worth an essentially $40 price point.' You can find a lot of great mandelic acid formulas, particularly within Korean skincare, for $30 and under."