Can Botox reduce muscle mass in arms or legs?

Cosmetically muscle mass reduction has been done with Botox in the masseter muscles (chewing muscles) of the face, but the number of units injected for this would be much, much less than that needed to reduce the mass of  muscle in the calf or arm.  The units for the leg or arm may be so high that the treatment could be extremely unsafe.  Neurologists are accustomed to treating muscular dystrohies with large amounts of botox but this is for a functional, not cosmetic, problem.

Hi Gems.  Botox has been used in the way you are suggesting here, but we have never offered this at our practice.  

The first issue is that extremely high doses of Botox would be required to relax and atrophy the muscles.  This would be extremely costly and could be very dangerous.  Careful and ethical physicians would most likely not take on a request like this as it is not a well accepted use for Botox.

Consistent Botox injection into facial muscles can reduce the muscle mass by blocking the function of the muscles injected, causing the muscles to atrophy (or shrink) over time due to non-use. This effect of shrinking the muscles comes at the cost of muscle function. Botox is not intended to reshape the entire body. Not only would it take a huge amount of Botox to combat arm and leg muscles, but the function of your arm and leg muscles is not expendable. The best way to shrink these muscles is to not exercise them specifically. Also, is it really the muscle mass you are worried about, or overall volume? In most people excess arm or leg volume is fat, not muscle. If that is the case exercising and building those muscles will help burn the fat.

This is the basis for using BOTOX to treat muscle spasm.  The down side is muscle weakness and reduced function.  So it would not make sense to use BOTOX say to reduce calf muscle size.  Most people what bulk in their limb muscles.

The amount of Botox to do that would be incredibly large and that can have serious, even life-threatening side effects.

Don't do it even if someone offers you to do it for you.

 

It is not safe to use Botox to reduce muscle mass in your arms or legs. If there is a reason that you want reduced muscle mass, that isn't achieved merely by not exercising, see a nutritionist or general physician who specializes in the issues you are considering.

If there is any person who is suggesting to you that you can use Botox to achieve this goal, I would walk away fast. That sounds dangerous, unethical, and possibly illegal to me. Definitely do NOT consult with anyone about this issue who is not a board-certified plastic surgeon or neurologist.

Botox is indicated to decrease or stop muscle contractility in either spasms or cosmetically in producing frowning, scowling or interbrow, forehead and crow's feet wrinkles. It would be inordinately expensive and dangerous to inject it to reduce muscle size. Stopping muscle excercising is a much safer and cheaper way to do it without risking loss of use of those muscles.

Peter A Aldea, MD
Memphis, TN

only locally. If you have a facial treatment with Botox, the muscles in your arms or legs will not be affected.

If you plan to reduce the muscle mass in your arms or legs the answer is clear: stop exercising. A not trained muscle looses its mass quickly. 

Botox is sometimes used to perform calf reduction by shrinking the size of the calf muscles. The Botox needs to be given very carefully by an experienced injector. This is an advanced application that is considered off label use. There is a small risk of reduced function.

Botox is not used specifically for this purpose and I doubt it would have any effect.  Nor do I think anyone would do this for you.