Does castor oil work for your eyelashes and skin?
For eyelid inflammation and dark circles there are small positive studies, but the evidence is too thin for firm conclusions. The popular use for eyelash growth in healthy individuals has no clinical backing.
Castor oil for eyelid inflammation (blepharitis) has the strongest clinical backing of all its applications. In a small randomised trial with 26 participants, applying the oil to the eyelid margins twice a day for four weeks produced clear improvements: fewer eyelash crusts, less thickening of the eyelid margin, and less eyelash loss. No side effects were reported. It is a small study, so the finding needs confirmation, but it was designed as a controlled trial.
For dark circles under the eyes there is preliminary evidence. A study in 22 patients found that applying a cream twice a day for two months reduced darkness, pigmentation, and wrinkles. However, there was no placebo group, so it is impossible to know how much of the effect would have occurred without the oil. The researchers themselves state that larger, controlled studies are needed.
Castor oil is also mentioned as a possible option for dry eyes caused by meibomian gland dysfunction. This is based on a review article, however, not on the researchers' own trial participants. The idea is plausible because the oil may slow moisture loss, but solid clinical evidence is still lacking.
Two other mentions are less relevant for everyday users. In nail fungus treatment, castor oil is only an excipient in a formula that contains actual antifungal agents; the contribution of the oil itself cannot be isolated. Stories on social media about castor oil combined with nutritional yeast for hair and nails are personal accounts from internet users, not clinical research. No conclusions can be drawn from them.
The popular use of castor oil for eyelash growth (thicker, longer) is not supported by any of the controlled studies. The only eyelash-related outcome in the available research concerns reduced shedding in blepharitis, not growth in healthy eyelashes. Do not expect miracles on that front.
All claims based on PMID 32422285, 41931217, 37927123, 40311119, 15069427, and 28906086. None of the studies is large or robustly designed; no meta-analyses are available.
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.
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.
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.
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.
Do exosomes in skincare really work?
There are preliminary indications that exosomes may do something for the skin, but the clinical evidence is very thin: one small study without a control group and otherwise mainly animal research. Do not buy into the hype just yet, but keep an eye on the research over the coming years.
Can your skin get used to retinol so that it becomes less effective?
Your skin gets used to the side effects of retinol, such as flaking and redness, but not to the effect itself; the active effect on lines and pigmentation does not diminish with longer use.