Disclaimer: I am not an expert in Ayurveda by any means.
Ayurveda, like Yoga, is seeing a resurgence in popularity. Both as an alternative medicine as well as in skin care. I am going to focus on skin care as that's where my personal interest lies.
My research on Ayurvedic skin care is entirely based on published papers. Thankfully, there are a few obscure academic groups in India that have published papers on subjects such as chemical composition and biological action of Ayurvedic remedies. In addition, my mother and mother-in-law have passed on to me some personal grooming traditions that they grew up with that are based on Ayurveda. Of course, this knowledge is protocol based and has almost no scientific explanation. Having grown up in India, Ayurvedic methods were part of daily life. I went through the phase of discarding these grooming practices and now have come full circle to adopting some practices primarily because I found scientific backing for some of these methods and ingredients. I have also found that there are some ingredients used in Ayurveda that are "primitively" made - there are much better ways to make them today since we understand what is the exact chemical composition of these substances. I am quite fascinated by Ayurvedic methods - the kashayamas, thailams, Bhasmas, churnas - they have this mysterious, alchemical appeal. But I am careful not to romanticize this approach - I always look for chemical compositions and how they work. In the end, molecular identity is the truth no matter what method you take to get to it.
Recently, I have been focused on what causes hollowness under the eyes as we age. Mainly because I have them and I don't like it (all that stuff people say politely to me about not looking like a mother of a 15 year old has gone to my head. I am doing yoga to stop being so vain - but that's another story). Anyways, my research led me to a fascinating paper on an Ayurvedic "anti aging" preparation involving cow ghee, flaxseed oil, a resin called Shorea robusta, and Yashada bhasma. The Yashada bhasma caught my attention - it has this mysterious ring to it, doesn't it? Yashada is zinc. Bhasma is ash. So I put the two together and figured that Yashada bhasma must primarily be ZnO or zinc oxide. The paper did not really talk about the composition of this bhasma but the conclusion was that this particular combination of ingredients showed better wound healing and collagen content in skin compared to a control group. I found out that Yashada bhasma is made in a rather elaborate way - see below the materials needed to prepare this bhasma:
Zinc metal is melted, quenched in sesame oil and then treated with a variety of liquids - buttermilk, cow urine, kanji etc. The idea is to treat the metal with acidic (buttermilk) and basic (cow urine) media to enable the end product to be easily incinerated to a nanometer size granular powder. The function of the other herbs is to assist with purification of the zinc. In the end, the composition of the powder was determined to be ZnO with a particle size between 150-800nm. This is basically nano zinc oxide powder that can be found in sunscreens, diaper rash ointments etc.
It is indeed impressive that all this could be done using commonly available material without a well stocked chemistry lab. Simply amazing. However, would I make nano zinc oxide using this method today? I don't think so.
So now, let's talk about what ZnO does for skin. I found a very comprehensive paper on a variety of studies done on animals and humans using topical application of ZnO. Since my original goal was to see how to prevent hollow eyes non invasively, I will put this in the context of aging.
So it may be beneficial to use products using ZnO - like a sunscreen for example.