The formation of facial wrinkles is associated with aging of the skin itself, photodamage, gravity, trauma, subcutaneous tissue atrophy and facial muscle activity. Compared with surgical wrinkle removal, laser wrinkle removal and skin soft tissue filling techniques, the most widely used is Botulinum toxin injection for wrinkle removal, which can eliminate the role of muscle contraction in the formation of wrinkles, such as for the crow’s feet (power wrinkles), forehead wrinkles (power wrinkles), nasolabial folds (mixed wrinkles) can be significantly improved. There are three types of botulinum toxin type A used in clinical practice: Botox produced in the United States, Dysport produced in the United Kingdom, and BTX-A produced in China. In terms of potency, 1U of BTX-A is equal to 1U of Botox and 3-5U of Dysport. Botulinum toxin acts on nerves in three steps: ★ Botulinum toxin binds to a special membrane receptor on presynaptic cholinergic neurons; ★ The toxin-receptor complex enters the nerve endings through cellular swallowing; ★ The toxin prevents the release of acetylcholine from the cell through cleavage of certain proteins. Through the above process, this can lead to muscle fibers no longer producing contraction. Botulinum toxin does not block the propagation of nerve excitation, and there is no excitatory or conductive damage to nerves or muscles, an effect also known as chemical denervation. Clinical Application of Botulinum Toxin Type A In 1987, Canadian doctors conducted a successful clinical study on the use of Botulinum Toxin Type A injections for the removal of frown lines between the eyebrows, and in April 2002, the U.S. Food and Drug Administration (FDA) approved the use of Botulinum Toxin Type A for the treatment of frown lines between the eyebrows. Advantages of Botulinum Toxin A Wrinkle Reduction Advantages Compared with surgery, Botulinum Toxin Wrinkle Reduction is simple, anesthesia-free, painless, fast-acting, effective, repeatable, and free of serious complications and after-effects. Botulinum toxin combined with collagen can better remove static wrinkles and dynamic wrinkles. Indications of Type A Botulinum Toxin Injection for Wrinkle Removal Type A Botulinum Toxin is effective in removing dynamic wrinkles formed by muscle contraction in middle and young people. Clinical observation found that Botulinum toxin type A injection is also effective in removing wrinkles of the elderly, but the difference with the middle and young people is that the wrinkles of the elderly are deeper and furrowed, and the wrinkles will only become lighter after injection of Botulinum toxin type A, instead of disappearing completely. Storage, Preparation and Injection of Botulinum toxin type A Botulinum toxin type A is supplied in lyophilized crystalline form. Due to its extreme instability, it has to be stored in a refrigerator at -5℃, and then taken out and placed at room temperature for 10-15 minutes before use. Generally, dissolve 100U of botulinum toxin type A in 2.5~4.0ml of saline to avoid shaking bubbles and thus reduce the potency, and the concentration of botulinum toxin type A per 0.1ml of saline should be 2.5~4.0U. The concentration of botulinum toxin type A should not be more than 5U/0.1ml because the paralytic effect does not increase with a high concentration, but rather involves more neighboring muscles and causes side effects. Side effects may be caused by the involvement of more neighboring muscles. The prepared solution should be drawn from a 1ml syringe and injected with a 30-gauge needle, and the remaining solution should be stored in a refrigerator at 2-8 ℃ for a maximum of 4 hours. When injecting, the patient is seated, carefully sterilized, and the injector wears gloves. The injector should wear gloves. The patient should be asked to frown, lift the forehead and smile to define the extent of the wrinkles, and mark the muscle bulge between the wrinkles as the injection point. For deeper muscles, such as frown muscles and frontalis muscles, the toxin must be injected deeply into the muscle; thin orbicularis oculi and interlobularis muscles respond better to superficial application of the drug, so the drug can be used subcutaneously. Because botulinum toxin type A can spread up to 2.5-3cm around the injection point, in order to prevent complications, the injection dose should be small. When injecting in the forehead, avoid involving the frontalis muscle 1cm above the eyebrow so as not to affect the lifting of the eyebrow, both sides of the injection point should be symmetrical, and the injection dosage should generally be equal so as not to cause asymmetry on both sides. When injecting crow’s feet, the injection point should be at least 1cm away from the corner of the outer canthus to avoid affecting the function of orbicularis oculi muscle and the surrounding expression muscles, resulting in an unnatural expression, or even causing the lower eyelid ectropion. For nasolabial folds, the injection point is the beginning of zygomaticus major muscle away from the corner of the mouth, i.e., at the level of the lower edge of the orbicularis oculi muscle of the lower eyelid. For perioral wrinkles, a tiny amount of botulinum toxin (1 to 2 U) can be injected superficially under the skin on each side of the lip. For drooping corners of the mouth, 2-3U of Botulinum Toxin can be injected into the descending corners of the mouth on each side. The efficacy of botulinum toxin A injection for wrinkle reduction is generally observed. 1-3 days after botulinum toxin A injection, the muscles begin to relax, and there is a “tight” feeling locally; 7-14 days after the injection, the muscles are completely relaxed and paralyzed, and the skin is smooth, and the wrinkles disappear or become lighter; the efficacy of the treatment is maintained for an average of 6 months. This is because botulinum toxin acts on the nerve-muscle bond at the same time, the myelin sheath of the presynaptic neuron regeneration, and the formation of new synapses near the old synapses, and then the release of acetylcholine, the function of the muscle can be restored, the effect of wrinkles will disappear, the process of an average of 6 months.