Common areas for dynamic wrinkles on the face include the forehead, the glabella, and the crow's feet. Forehead wrinkles form when lifting the head or eyebrows, known as "worry lines." Glabellar wrinkles form when frowning or thinking, also known as "frown lines." The crow's feet are wrinkles that form when making certain facial expressions, such as squinting or smiling, due to the contraction of the muscles outside the eyeballs.

In addition to common wrinkle-reducing and facial slimming purposes, botulinum toxin has a wide range of medical uses, such as injections into muscles, the bladder, and even the vocal cords. Compared to medical uses, the dosage required for wrinkle reduction and facial slimming treatments is relatively low, making it safer. However, botulinum toxin is still regulated in Hong Kong and must be purchased, prescribed, and injected by qualified doctors to reduce risks.

Botulinum toxin may cause temporary side effects. According to the US Food and Drug Administration, possible side effects of botulinum toxin injections for wrinkle reduction include bruising, muscle soreness, and headaches. If the dosage and location of the injection are improper, or if postoperative care is inadequate, botulinum toxin may spread to muscles not intended for the treatment, causing symptoms such as drooping of the eyebrows or eyelids or a stiff expression. However, once botulinum toxin is metabolized, the side effects will disappear, and no permanent side effects will occur.

The human body can produce antibodies to neutralize botulinum toxin, which may cause a decrease in effectiveness after multiple treatments. Using impure botulinum toxin products may increase the risk of antibody production.

In other words, if an individual receives injections of impure botulinum toxin for an extended period, there is a chance that resistance to the treatment may develop, making it challenging to achieve wrinkle reduction or other cosmetic purposes with the exact dosage. Once antibodies develop, in the long run, they may render the medical use of botulinum toxin ineffective. Please consult with a doctor to reduce the risk of developing resistance.

In general, people who are sensitive to botulinum toxin, have infections at the injection site, pregnant or breastfeeding women, and long-term patients such as those with myasthenia gravis or Lambert-Eaton syndrome should not receive injections. If there are any doubts, please consult a doctor to evaluate the body's condition and rule out potential contraindications.