Will Electric Stimulation Machines Help Firm Facial Muscles?

Electrical stimulation devices claim to use low level "micro current" to stimulate facial tone and sculpt the face. While they may provide a very small benefit, they do not prevent or correct facial aging and cannot be used as an alternative to face lift. 
It is important to remember that aging is more than just "skin deep" and its not just about the muscle.. A lot of aging has to do with the deeper structures of the face. Specifically, we lose critical bone and fat from our face as we age. The bone and deep fat are structurally important and are needed to support and provide contour to the overlying skin. The skin itself also ages, becomes increasingly inelastic and can no longer hold its shape resulting in "static wrinkles" and pleats. Finally, the deep fibrous network that anchors our skin to the bone also weakens over time. All these age changes boost the effect of gravity resulting in sagging jowls and necks.
The more you understand about facial aging the clearer it becomes that there are no magic solutions or devices.

Great question!
I think the best comparison I can give is when people try to do lots of abdominal workouts to help lose abdominal fat. This unfortunately doesn't work, however once they lose some weight the abdominal muscles are much more well defined. Similarly in the face, working out these muscles may make them larger or more toned, but it may not ultimately show significantly given the overlying soft tissue/skin/parotid gland/etc. All that being said, it is unlikely to cause any issues and generally any type of exercise is good for the body as long as your electrical stimulation machine is safe and regulated.
Hope this helps!

This is a myth, to work on your facial muscles to get them firmer. It is nor correct to compare such procedures with procedures like facelifts that rejuvenate the face in a radical manner.
Hope this helps,
Ali Rıza Öreroğlu, MD FEBOPRASEuropean and Turkish Board Certified Aesthetic, Plastic and Reconstructive SurgeonIstanbul, Turkey

There are some studies showing improvements albeit mild on patients who do certain facial excercise over a long period of time.  Electrical stimulation may mimic such excercises by stimulating muscle contracture.  But it seems like a arduous way to seek very mild rejuvenative benefits, i.e. a long run for a short slide. 

A TENS unit or (Transcutaneous Electrical Nerve Stimulation) machine may be good for chronic condition such as back pain or with help in facial nerve disorders after injury to the facial nerve (cranial nerve VII), however, to my knowledge, there has been no randomized controlled study to show any efficacy in tightening the muscles or skin of the face. The muscles and their covering the SMAS need lifting and repositioning. The overlying skin will need tailoring and any areas of excess fat will need to be sculpted. This is traditionally done, in my practice, through a high-lamellar or deep plane facelift whereby the retaining ligaments of the face are lysed and the mid face as well as lower face can be rejuvenated. Please consult only with board-certified facial plastic or plastic surgeons when having someone perform this operation. 

It would be best to save your money. Stimulating your face with a machine will not likely work. Thanks