The skincare industry has no shortage of exotic ingredients. Here are the ones with consistent clinical evidence behind them, and the ones that are mostly marketing.
Well-evidenced actives
Vitamin C (L-ascorbic acid) at 10-20% is a well-established antioxidant and brightener. The formulation matters enormously — pH below 3.5 and opaque packaging are not optional.
Niacinamide at 2-5% reliably reduces oil production and improves barrier function. It is also one of the least irritating actives available, which makes it ideal for beginners.
Retinoids have the strongest evidence base of any topical for photoaging. Start at 0.025% twice weekly and build up.
Mostly marketing
Snail mucin, "24k gold" and most botanical extracts have little controlled trial evidence for topical use in humans. That does not mean they are dangerous — they are probably fine and probably not doing very much either.
How to read a label
Percentages matter more than order on some formulations, less on others. If a brand does not disclose the percentage, assume the active is present at a level too low to matter.