I’ve been using a salve of the comfrey root and its flowers on my head for the last four years, it has stopped my hair loss and has regrown hair in my residing hairline. I did this experiment on myself based on the fact that comfrey contains a chemical compound called allantoin which is a cell rejuvenator. My barber will testify.
This appears to be a product with extensive claims that run the gamut — gum disease, hair care, hair damage, hair growth, hair loss, halitosis — and have no basis. If you believe in this product, I would suggest that the readers take notice of my slogan. Let the buyer beware.
There is generally interesting information about comfrey root, its history and much about its growth and use at Wikipedia. Many, many herbs are used for various conditions and when they work for one of these conditions, the person becomes an advocate. This type of advocacy is not scientific. We only know the successes and not the frequency of failures, because advocates do not talk about the failures. For the advocate, it may reflect their pride of authorship and an individual’s need to contribute to the welfare of fellow human beings, but as a clinician, if I recommend something (even an herbal type of product like comfrey root) I want to have evidence of its effectiveness and its safety.