Herbs that constrict tissues are known as astringents. Cosmetically, astringents are commonly used to tone or tighten skin, giving it a smoother appearance. By restricting glandular secretions and dissolving surface oil, they are also able to control facial oil.
Active Constituents
The major components responsible for the astringent activity are tannic acids, or tannins, as they are more commonly known. Additionally, most herbs, when burned, acquire astringent properties, even when none are inherently present.
Mode of Action
The tightening and drying effects of tannins are achieved through contraction of immediate muscle fibers and reduction in permeability of cell membranes.
Commonly Used Herbal Astringents
Oak bark (Quercus alba/robus), bayberry root bark (Myrica cerifera), raspberry leaf (Rubus idaeus), yarrow leaf and flower (Achillea millefolium), witch hazel bark and leaf (Hamamelis virginica), white pine inner bark (Pinus strobus/alba), chamomile flower (Matricaria recutita) and calendula flower (Calendula officinalis) are some example of herbs with astringent properties.
Preparation and Application
Depending on how tough the herbal matter is---whether it's a flower, leaf or bark---it may either be decocted (simmered) or infused (steeped in hot water) for about half hour. Astringents are typically applied to skin between washing and moisturizing.
Considerations
It is very important to consider individual skin type and be mindful of potential allergic reactions or excessive dryness.
