Botulinum toxin is a liquid toxin that is used for loosening specific muscles contributing to the formation of wrinkles (dynamic wrinkles formed by facial mimicry). The substance is injected directly into a muscle and the effect lasts for 4 to 6 months. Hyaluronic acid is a natural gel-like substance that is injected in the skin or under it. Due to its property to bind water it increases the volume of tissue and thus decreases wrinkles resulting from aging and smooths the skin.