Does drinking lots of water really help against dry skin and wrinkles?
Drinking extra water probably helps a little with dry skin, especially if you were chronically under-hydrated, but its effect on wrinkles has not yet been proven. Make sure you drink enough, but do not expect a dramatic result for your skin.
Drinking more water slightly improves the moisture level of the outermost skin layer, but this effect is most noticeable in people who were already chronically under-hydrated. Small improvements in dryness, roughness and skin elasticity have been observed, but the studies examining this were limited in number and quality. On the basis of this research, cause and effect has not yet been established.
For wrinkles, the picture is more nuanced. A small study of 128 women aged 40 and older showed that low water intake was associated with more wrinkles, but only in women with a specific genetic risk profile for collagen breakdown. UV exposure and menopause also played a major role. This is therefore not evidence that drinking water prevents wrinkles in everyone.
Regarding the effects of water intake on matters such as sebum production and skin pH, the studies yield contradictory results. No meaningful conclusion can be drawn on this.
What is more firmly supported: chronically drinking too little, identifiable through a high sodium level in the blood, appears to go hand in hand with accelerated biological ageing and a higher risk of chronic diseases. Whether this association is truly causal is currently being investigated in ongoing studies.
A practical note: you cannot rely on thirst or urine colour to assess whether you are drinking enough, especially at an older age. These signals turn out to be individually unreliable. A systematic review found that common 'just check your urine' rules of thumb do not measure this well in older adults.
This answer is based on two systematic reviews, a Cochrane review, a narrative review and a small study of 128 women. The systematic reviews cover only six studies on skin hydration and are methodologically weak. The narrative review was co-authored by three authors employed by PepsiCo, which is a factor to weigh when evaluating the findings on skin health. The Cochrane review on dehydration signals in older adults is methodologically stronger. The evidence on wrinkles rests on a single small study and is therefore thin.
Does hyaluronic acid applied to your skin actually help against dryness and wrinkles?
Hyaluronic acid on your skin genuinely helps against dryness. Injections work most powerfully against wrinkles. A pill or powder adds little if you are already taking collagen.
What actually works against skin aging?
Using sunscreen daily is the best-supported way to slow skin ageing, supplemented by not smoking, moderate alcohol consumption and sufficient sleep. Cosmetic options such as thread lifts and honey in creams have a weaker or not yet sufficiently proven basis and call for a critical weighing of the risks.
Does retinol help against wrinkles?
Retinol demonstrably works against wrinkles and improves skin texture, although tretinoin is more potent for those who can or wish to obtain a prescription; people who experience irritation may consider bakuchiol as an equivalent alternative based on one small study.
Does taking collagen supplements actually work against wrinkles?
Taking hydrolysed collagen reduces wrinkles and improves hydration and elasticity, although the effects are modest and no established dose exists. Most studies used 2.5 to 10 grams per day for 8 to 16 weeks; marketing promises of spectacular skin rejuvenation are exaggerated.
Do AHAs or BHAs really help against wrinkles and blemishes?
Both AHA (glycolic acid) and BHA (salicylic acid) demonstrably help against acne, blemishes and, to a lesser extent, wrinkles, although the effect varies from person to person. For acne, salicylic acid has the strongest evidence base, particularly for darker skin tones.
Does resveratrol in skin cream actually do anything?
Resveratrol in skin cream demonstrably reaches the skin and has antioxidant activity, but whether it produces any visible effect as the sole active ingredient has not yet been proven. Combination products show promising results, but anyone buying a cream with resveratrol should be aware that the evidence for resveratrol itself remains thin.