Here is an interesting question from Claire
Hi Colin, I was looking at some eye drops today for tired eyes (optrex- I think it was the refreshing ones) and I noticed that witch hazel and alcohol were listed as ingredients, I though that both of those were astringent and I can’t see how they could make eyes feel better. Could you give me an idea why they might be there? Thanks! Claire
Two ingredients listed, but I think we are only talking about one raw material here.
Witch hazel is extracted from the twigs and leaves of the witch hazel bush (Hamamelis virginiana – you will see this latin name on ingredient lists). The extraction technique includes alcohol some of which carries over into the witch hazel and that is I imagine where the alcohol comes from.
Witch hazel is as you say an astringent. But what do we mean by that? It is one of those terms that often gets bandied about. It is usually thought of as a sort of shrinking of the skin. That is how it feels, but is it really what is going on? I haven’t found an official definition. But you don’t need a definition to know what something is. I don’t suppose many of us could define and elephant, but we know what one is when we see one.
So remembering having had witch hazel applied to bruises when I was a kid, the astringent experience was intense pain, a feeling of tightening of the skin and then a numbing of the pain that kicked in a little later. I don’t know exactly what was happening, but I imagine it is something to do with the pain receptors in the skin being shut down. Left to itself the skin has an adequate blood supply and networks of nerves. Attacking it with something that does some limited local damage would have the effect of dulling the pain sensation – once they have been triggered they will be depleted for a period and so you won’t feel so much pain and irritation. This might well also have the effect of provoking an inflammatory reaction.
If I am right then I would have to agree with Claire. It is not a good idea to have witch hazel in eye drops. But I doubt that there is very much in the formulation. I expect it is just a nominal amount to make it sound nice. Most people don’t think these things through too logically so the marketing team might well have just wanted to make a story. Witch hazel is associated with healing, so in it goes. Or that is my opinion anyway. I did do one project on eye drops once, but I wouldn’t claim to be an expert.