I have a friend who told me that anti-aging cream cannot work to reduce wrinkles as it only penetrates x amount of skin layers and can never make a long term effect. Me not knowing much about how penetrative skin actually is, I was wondering if anyone knows if this is true and if anti-aging products are only working like a temporary moisturiser?
Since there are different formulations for anti-aging creams, it would be helpful to focus on the specific compound or combination of compounds.
According to a comprehensive literature review done in 2007, certain compounds (Vitamin C, alpha-hydroxy acids, Vitamin A, Vitamin B derivatives, and botanicals) have had varied success in literature demonstrating anti-aging efficacy with Vitamin C and alpha-hydroxy acids being the better candidates.
Vitamin A/retinols have been shown to reduce wrinkles in some studies but no large studies have been conducted to show efficacy, Vitamin C has been shown to be the most effective (statistically significant improvement in texture, wrinkling, etc.) and alpha-hydroxy acids have been shown to increase collagen density, for example among other improvements. A lot of these and other compounds have had positive or encouraging results replicated in literature, on mostly animal and human cell models so whether they actually have a significant effect on a large group of people needs to be looked at but to assess whether or not they actually "work" depends on what issues of skin damage as a result of aging one is targetting, the severity, the age at "treatment" and whether you're referring to over the counter or prescription-strength.
Huang, C. K. and T. A. Miller (2007). "The truth about over-the-counter topical anti-aging products: a comprehensive review." Aesthet Surg J 27(4): 402-412; quiz 413-405.