What are dynamic wrinkles? Ageing is accompanied by the appearance of two types of wrinkles: dynamic wrinkles caused by muscle over-activity, frown (or glabella) lines belong to this category, and static wrinkles associated with loss of volume: nasogenian creases (semi-circular lines marking the boundary of the cheek and the mouth area) are an example of these. Repeated muscle contraction leads to the appearance of dynamic wrinkles. What is BOTOX? Nerve endings release a chemical substance, acetylcholine, which transmits contraction information to the muscle. BOTOX is a type A botulinum toxin whose role it is to temporarily block the release of acetylcholine. The muscle is then relaxed and the wrinkle is.