We communicate with facial expressions that reflect our feelings and emotions. Facial expressions are the result of muscle contractions. Over time, with repeated facial expressions these contractions create visible lines and grooves which make us look older and can be even misconstrued as fatigue, anger, anxiety, sadness and fear. The grooves and wrinkles caused by the muscles of facial expression are called dynamic wrinkles

What are neurotoxins and how do they work?

Neurotoxins are wrinkle relaxers for nonsurgical facial rejuvenation. Neurotoxins are injectables containing the neuromodulating substance botulinum toxin A. They are used aesthetically to reduce muscle activity that causes dynamic wrinkles at the brow, crow’s feet, bunny lines, lines around the mouth, dimpled chin, mouth frowns, platysmal bands and horizonal neck lines.

Injection of neurotoxins temporarily relaxes the muscles of facial expression and smooths dynamic wrinkles. When injected by an expert, they will not eliminate facial expressions. However, neurotoxin injections can treat and prevent unintentional habits such as facial grimacing. When received on a regular schedule, injections can even prevent formation of new dynamic wrinkles and reduce the severity of existing dynamic wrinkles.

Injections of neurotoxins do not stop the aging process but can help to slow the visible signs of aging caused by muscle contractions. Treatment is quick and easy with no downtime and in the right hands can produce superior results. Nonsurgical facial rejuvenation can improve your quality of life and satisfaction with your appearance with great safety profile. However, results are technique dependent.

What happens during this procedure?

When treating fine lines and wrinkles, the dermatologist injects a small amount of botulinum toxin into targeted muscles on the face or neck. This temporarily relaxes the targeted muscles, causing fine lines and wrinkles to diminish. The effect lasts about 3 to 4 months and sometimes longer.

Will I lack facial expressions after treatment?

Dermatologists want their patients to look natural. To do this, they inject just enough to weaken and relax the targeted muscles without affecting other muscles. This allows patients to maintain their natural facial expressions.

Will I lose my sense of feeling where I have the injections?

No. This treatment does not affect your ability to feel.

When is it safe to have another treatment?

You can have another treatment when the excessive sweating or lines and wrinkles return. With repeat treatment for lines and wrinkles, the muscle may thin, leading to longer-lasting results.

Is there downtime?

Most people return to the everyday activities immediately. As soon as you leave the treatment room, you can apply makeup.

What must I do after the procedure?

To prevent the injected substance from spreading to areas where you do not want it, you’ll need to take a few precautions:

  • Do not rub or massage the areas where you received the injections.
  • If you apply makeup, take care not to press or rub it in.
  • Wait two hours before you engage in strenuous physical activity. This includes lifting heavy items, working out, and any other physical activity that raises your heart rate.

Vital information to tell your dermatologist

If you decide to have botulinum toxin therapy, be sure to give your dermatologist the following information:

  • All medicines you take. Be sure your dermatologist knows about all pain-relievers, blood thinners, and other medicines. Include medicines that you buy without a prescription, such as aspirin.
  • All herbs, vitamins, and minerals you take. Even if you haven’t taken these for a while, be sure to mention them.
  • If you are pregnant or plan to become pregnant. It is not known whether botulinum toxin therapy can harm an unborn child.
  • All surgeries and cosmetic treatments you have had. While some patients feel embarrassed talking about this, the information you share can make a difference in the results you see.

Brands of Neurotoxins

There are four FDA approved neurotoxins:

  • Botox® is the most popular and the name is commonly used to represent all neurotoxins. It contains the active ingredient – botulinum toxin A. Botox onset is usually 2-3 days. The results are reliable and predictable.
  • Dysport® works the same as Botox but has a unique formula with different characteristics. Dysport has a faster onset of 1-2 days after treatment and may last longer than Botox for some patients.
  • Xeomin® is another injectable neurotoxin with slight differences from Botox. It was created to reduce the risk of developing resistance to Botox. Xeomin works like Botox with the same duration, dosing and onset time; Patients who don’t achieve the desired effects from Botox or Dysport may have a better response with Xeomin. Effects last 3-5 months.
  • Jeuveau is a newer formulation and a Botox alternative and has been designed for cosmetic purposes only. The safety and effectiveness are similar to Botox. Onset is usually 2-3 days and lasts about 3-5 months. Duration may vary depending on individual’s metabolism.

What are the neurotoxin applications?

The most common application is to treat deep forehead creases, brow lines, furrows, vertical glabellar lines also known as the ‘angry 11s” and crow’s feet. Expanded use based on experience and efficacy include:

  • To smooth chin dimpling caused by chin muscle contractions
  • To diminish bunny lines on the nose
  • To improve gummy- smile and soften nasolabial folds, the grooves that run from the corners of the nose to the corners of the mouth
  • To reduce the appearance of deep upper lip lines
  • To enhance facial symmetry
  • To lift the corners of the mouth by relaxing the muscles that pull down the corners of the mouth which will reduce the appearance of marionette lines from the corners of the mouth to the chin and improve your smile!
  • To create a chemical browlift by raising and leveling droopy brows to open the eyes and raises the brow for a more rested appearance.
  • Release and smooth neck bands sometimes referred to a chemical neck lift. Only treating the face and leaving the neck bands and jowls will give age away. The neck muscles can be relaxed to reduce their pull on the jawline and lift the jowls.
  • Reshape a square jaw line. Injections into the muscles of the jaw can reduce the appearance of a square jaw, soften the shape of the face, and make your lower face appear slimmer.


The key to success with neurotoxins is injector expertise. Dr Hashemi is a board-certified dermatologist in Sacramento California. She is a Castle Connolly Top Doctor and specializes in skin cancer, cosmetic and laser surgery. Dr. Hashemi is also an expert aesthetic injector of dermal fillers and neurotoxins. Contact us at The University Skin Institute to schedule a consultation with her and learn about all cosmetic services she offers.