Spirea Ulmaria Meadowsweet Extract reduces the activity of the sebaceous glands by inhibiting the activity of 5a-reductase; it should limit the amount of sebum secretion due to an astringent effect by its tannins; and it may prevent acne that is caused by bacterial proliferation. The enzyme 5a-reductase is accountable for the production of the androgen hormone dihydrotestosterone that generates the sebaceous glands’ activation, and so by inhibiting 5a-reductase, it can considerably reduce the amount of sebum produced. Furthermore an astringent effect is produced by tannins because tannins are able to constrict tissues and contract the pore openings in the skin. Lastly because there is a decline in the accumulation of sebum within the pilo-sebaceous channel, there should be less bacterial proliferation which leads to a decrease in problem skin and should provide a healthier overall appearance.The specific tannins that are responsible for its astringent properties are gallotannins and ellagitannins, which act as natural astringents and regulates the skin and may reduce complications resulting from excessive sebum production and thus helps to maintain a healthy balance on the surface and interior of the skin so that we can avoid overly oily or dry skin. A very useful ingredient for inclusion in all problem skin cosmetics.