Does Botox Cause Muscle Atrophy?

Dr Yang – is it true that relaxing the muscles with Botox so they don’t form creases (which definitely helps with wrinkles) cause your muscles to atrophy and lose facial volume faster?

This seems to be a win-lose situation if true.

And, if true, would the areas usually treated with Botox be a concern for loss of volume, like the 11′s and crow’s feet areas?


Hi foxeskier,

Botox temporarily paralyzes the muscle. It’s like putting a muscle in a cast for 2-3 months. When the cast comes off, the muscle is much weaker, even though you can still move it. If a body builder breaks their arm and has huge biceps. When the cast comes off the bicep will like become atrophied and smaller. If you compare the two arms afterwards, the arms that had been in a cast will likely be much smaller than the other arm.

Now let’s take a 90 pound “weakling” as an alternative example. Let’s say for argument’s sake the 90 pound weakling breaks his arm. If you put his arm in a cast for the same amount of time and then compared the two arms, you may not see much, if any difference, since the 90 pound weakling’s arms were already atrophied to begin with.

There are some men and women, who are older and just don’t have any frown lines. In general they don’t frown very much. So their “frowning muscles” or corrugator muscles are like the 90 pound weakling’s biceps. They were just very small corrugator muscles to begin with. They also have the benefit of not having any frown lines.

For men and women with very deep frown lines, their corrugator muscles are overactive or “hyperdynamic” from overuse. The repetitive frowning begins to form deeper and deeper creases between the eyebrows, despite the fact the corrugator muscles are very strong. The corrugator muscles are likely “hypertrophied” or larger than the person’s corrugator muscle which is normal sized or atrophied, yet all of the bulk of the corrugator muscle doesn’t fill in the deep frown line at all. Over time the stronger the muscle gets and the deeper the frown line “etches” itself into the skin, even Botox may not be able to smooth out the frown line completely. Although the frown line may improve with Botox, the repetitive frowning has causes a loss of volume along the frown line groove which doesn’t fill out even with Botox.

Let’s look at this woman with moderately deep frown lines. Her corrugator muscles are hypertrophied, yet the volume of the corrugator is not helping her look younger around the eyelid and brow area. Would Botox help her? If so, would the thinner atrophied corrugator muscle make her look worse? or better?

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Botox is mainly used for the 11′s or frown lines, crow’s feet, and forehead. Yet when we discuss facial volume loss, do we talk about fat grafting the frown lines, crow’s feet or forehead? No, the cheeks/orbital rims, temples, cheek hollows, and jawline lose volume, yet we don’t inject any Botox there, and facial volume loss occurs naturally in those area.

The cheek fat pad is the prototypical example of facial fat atrophy. The cheek fat pad is round and dome shaped like the top of a hamburger bun.

There are the smiling muscles underneath the cheek fat pad, but they are very thin.

Take a look at the diagonal muscles on the cheek. There are the levator labii muscles, zygomaticus major and minor muscles, and risoris. Here is a “legend” to the facial muscles “map.”

The question for you is if I make the top of the hamburger bun half the thickness (cheek atrophy) will making the strips of bacon half their normal thickness or double the normal thickness make any difference in the overall size of the bacon cheeseburger.

The smiling muscles are much larger than the corrugator (frowning) muscle. Imagine a muscle which is the thickness of two index cards and the size of a Trident gum. If the muscle is atrophied, it may become one card thick and if it is bigger maybe three thick. The volume of the corrugator muscle doesn’t really contribute to and particular contour of the brow, but if it is overactive it create the 11′s or frown lines.

The win-lose situation is that the Botox helps to prevent these 11′s from getting worse and making them look better, but the lose part is that it only works for 2-4 months before the effects wear off, and to maintain the result it will just cost more money. If for some reason you think that the corrugator volume loss is making you look worse, then you have the option of never using Botox again. To regain the volume of the corrugator, you can intentionally frown a lot and you should be able to make the muscle hypertrophied again. Just kidding.

If you compare the risk of volume loss for a very thin Trident gum sized muscle with negligible volume to the benefit of the frown line reduction and prevention, you can come up with your own risk-benefit analysis.

I don’t know any injectors who use Botox on smiling muscles, so the volume of the smiling muscles should not be a factor in the loss of facial volume. Yet there seems to be plenty of Infomercials selling facial exercise systems or machines to “tone” our facial muscles. Just remember the thickness of the bacon and versus the volume of the top of a hamburger bun example for reference, and you can decide for yourself if it is worth the money.

Thanks for asking the question. I’ve been meaning to write something to put the facial exercising machines/exercise systems into perspective with some good analogies.


Dr. Yang