ExDancer
But HOW does the moisture get INTO your knee?
Hello Ex Dancer
The skin Is the largest organ in the human body, it covers the entire body. It is a permeable, meaning it's a two way barrier, allowing liquids to pass through it. It allows sweat and waste products to leave to enter the body, it allows draws moisture from the atmosphere.
Because it works as a two way barrier it also allows Medicines to be administered topically, provided the molecules are small enough to penetrate the outer layer (the epidermis).
The skin has three layers, the epidermis, the dermis which is the middle and the lower layer, the subcutis. The subcutis, houses the veins and arteries, the dermis is home to the capilliaries, the tiny threadlike veins.
If the molecules of any product applied to the skin are
Small enough to bypass the epidermis via the pores or hair follicles they can then pass into the dermis and the capilliaries and thus enter the blood stream and become part of the circulatory system.
This is how drugs can be administered. Unfortunately it is also the case that harmful chemicals can also enter the blood stream in the same manner.
There has been a huge growth in nanotechnology (making molecules small enough) hence the rise in topically administered drugs, and also the use of active anti aging ingredients in cosmetics. (Hyraulonic acid, retinol etc).
There is of course a downside ...... we are learning more about how some of these ingredients can be carcinogenic - some hair dyes for example.
Hope you find that helpful.