For how we live.
The brown facial patches come from overactive pigment cells in sun-aged skin. Triple-combination cream beats hydroquinone alone (risk ratio 1.58) and tranexamic acid helps, but relapse is the rule.
Topical retinol is the over-the-counter cousin of prescription tretinoin. In the cleanest test of the pure ingredient, three-times-a-week retinol beat its own vehicle on fine wrinkles and built new collagen — slowly.
Sun-driven brown patches are hard to shift. A Cochrane review found a triple-combination cream beat hydroquinone alone; newer meta-analyses point to tranexamic acid and PRP, on thinner evidence.
Tretinoin beats its own vehicle in randomised trials — though the vehicle does much of the work. In the few head-to-head trials against over-the-counter retinol, both arms improved and tretinoin irritated more.