Does drinking lots of water really help against dry skin and wrinkles?
Drinking more water improves the moisture level and suppleness of your skin a little, especially if you were not drinking enough before. That effect has not been shown for wrinkles.
Drinking extra water has a small, measurable effect on the moisture level of the outermost layer of skin. Six studies found a slight improvement, and skin elasticity and roughness also improved a little. But the effect was most pronounced in people who had been drinking too little to begin with. If you are already drinking enough, the benefit is probably small.
Wrinkles are a different story. There is not a single study showing that drinking more water reduces or slows wrinkles. The studies measure surface characteristics of the skin, such as moisture and roughness, but not how deeply the skin ages. In older people, the group most affected by wrinkles and dryness, the effects of drinking extra water have not yet been studied.
When it comes to moisture loss through the skin, oil production, and the acidity of the skin's surface, the studies contradict one another. No reliable conclusion is possible on those points.
An added complication for older people: the sensation of thirst becomes a less reliable signal as you age. Dehydration can therefore have progressed further before you notice it. If you are older, it is wise to actively keep track of how much you drink, even when you do not feel thirsty.
This answer is based on three combined reviews of existing studies. Research into water and skin is narrow: one of the reviews found only six studies that met the inclusion criteria, and the quality of those studies was low. The findings do not come from studies that ran long enough to measure skin ageing. None of the studies specifically looked at older people. The evidence therefore points in a positive direction, but is thin and of limited quality.
Does hyaluronic acid on your skin really help against dryness and wrinkles?
Hyaluronic acid on your skin genuinely helps against dryness. Injections work best against wrinkles. A pill or powder adds little if you are already taking collagen.
What really helps against skin ageing?
Using sunscreen every day is the best-supported way to slow skin ageing, complemented by not smoking, drinking alcohol in moderation and getting enough sleep. Cosmetic options such as thread lifts and honey in creams have a weaker or not yet sufficiently proven basis and call for a careful weighing of the risks.
Does retinol help against wrinkles?
Retinol demonstrably works against wrinkles and improves skin texture, although tretinoin is more powerful for those who can or want to obtain a prescription; people troubled by irritation may consider bakuchiol as an equally effective alternative based on one small study.
Does taking collagen really work against wrinkles?
Collagen supplements show positive effects on wrinkles and skin hydration in many studies, though most of those studies were funded by the industry.
Do AHAs or BHAs really help against wrinkles and blemishes?
Both AHA (glycolic acid) and BHA (salicylic acid) demonstrably help with acne, blemishes and, to a lesser extent, wrinkles, although results vary from person to person. For acne, salicylic acid has the strongest backing, especially for people with darker skin.
Does resveratrol in skin cream actually do anything?
Resveratrol has a demonstrated biological effect, but in ordinary creams the compound breaks down quickly, leaving little active ingredient by the time you apply it. Look for products with encapsulated formulations, as these handle the stability problem more effectively.