The body and especially the skin is exposed to many external environmental aggressors such as ultraviolet radiation, high energy visible light, infrared radiation, chemicals, pollution as well as cigarette smoke. To combat these external aggressors, you can take antioxidants orally or they can be used as an ingredient in skincare products.
Antioxidants taken by mouth, such as Resveratrol or Melatonin, are first absorbed into the bloodstream, then taken up by the liver and as a result they have low concentrations in the skin itself. So, it is actually best for these antioxidant ingredients to be applied topically in a skincare product. As our bodies and specifically our skin is exposed to these external aggressors, mainly during the day, traditional topical antioxidant ingredients, such as Vitamin C and Vitamin E are included in creams and serums that are applied in the morning.
Many people think of sleep as a passive process where the body just rests but in fact it is a very active process where the body, including your brain and your skin, is getting rid of toxins and actually repairing and regenerating itself. It has been shown that the skin is more permeable to skin care products at night time so, therefore, the products that you use at night are very important.
Resveratrol is a natural polyphenol derived from plants. It is a powerful antioxidant, chemoprotector, has anti-ageing benefits and can also lighten pigmentation. It is included in many skincare products but unfortunately if it is used in a day cream, it can be broken down by UV radiation to a more inactive form. Therefore, if it is used in a day cream, it must be combined with a high factor, broad spectrum sunscreen. The other alternative would be to use it in a night cream or serum but it should be formulated very carefully to make sure that the Resveratrol is actually delivered and absorbed into the skin.
It is recommended that this product only be used at night.
Melatonin is a natural hormone produced by the pineal gland in the brain and the secretion of this hormone is stimulated by darkness. In the evening when it becomes dark, the pineal gland produces more Melatonin, making you feel drowsy but it also has other positive effects – as an antioxidant it is a potent free radical scavenger as well as having both anti-inflammatory and anti-ageing benefits. The secretion of Melatonin by the pineal gland is reduced by daylight. In other words, Melatonin helps to regulate your normal circadian rhythm – your wake/sleep cycle – so at night time your body produces more Melatonin and during the day less.
As mentioned previously, if you take Melatonin by mouth very little actually reaches the skin. It therefore makes good sense to include Melatonin into a cream or serum to be used at night. Melatonin applied topically has been shown to increase hydration and tonicity of your skin, reduce skin roughness, has anti-ageing effects by improving wrinkles and it also promotes wound healing.
Production of Melatonin decreases with age so it is recommended that products which include this ingredient are especially useful in post-menopausal women with photo-ageing.
Ref: Protective Effects of Melatonin on the Skin: Future Perspectives. International Journal of Molecular Science 2019 Oct; 20(19): 4948.