Supplements containing hydrolysed collagen, readily available in vitamin shops, may well live up to the manufacturers' promises. Take 1-2 g a day and your skin ages less fast. At least, you could draw this conclusion from an animal study done at Tokyo University of Agriculture and Technology.
People who want to make their skin healthier and stronger have been using supplements containing gelatine and collagen for years. Whether these products actually work you can't tell from the studies. It's not unlikely, but it has never been investigated. That why the researchers wanted to know whether a collagen preparation – a hydrolysate of collagen from the scales of tilapia fish to be precise – protected the skin of naked mice against UV light.
Skin that’s exposed to ultraviolet light ages. The technical name for this is photoaging and it's the most common cause of skin aging in humans. If you can inhibit photoaging, you inhibit skin aging in general.
The animals used in the experiment were Hos-HR-1 mice. The researchers exposed the animals to a UV-B lamp three times a week for one minute, for five weeks in a row [UVB]. A control group was not exposed [UVB-].
Some of the UVB mice were given a collagen supplement every day [UVB+collagen]. The dose given was 0.2 g per kg bodyweight per day. To convert this to a dose for humans click here.
Using a corneometer, the researchers observed that the skin hydration decreased in the UVB mice, but not in the mice that were given collagen. The outer layer of the epidermis, the stratum corneum, or horny layer, thickened in the UVB mice, but not in the UVB+collagen group. And lastly, at the end of the experiment, the researchers found less type-1 collagen in the skin of the mice that had been exposed to UV light; and again, not in the UVB+collagen group.
The researchers suspect that the collagen supplement stimulates the skin cells to work harder, and as a result they are better able to deal with the UV radiation. The evidence is not hard, so they advocate more studies.
Biosci Biotechnol Biochem. 2009 Apr 23;73(4):930-2.