The internet is full of ads for portable home made devices for hair removal. All of them claim to remove hair permanently. The majority of these machines use electricity and gel. The gel is applied to the skin to increase the conductance of the current. The tweezers are connected to pair of electrical wires through which the current is transmitted. Each time you pick the hair with a tweezer the current zaps that hair. There is only a minute amount of current at very low voltage (just enough to light up a battery powered torch).
There are no needles used with these techniques. The current does not affect the hair follicle as hair has no conducting capacity.
These devices cost anywhere from $ 100-400, depending on whether you buy one or two machines (why someone would want two machines is puzzling).
In simple, you grasp a hair with a tweezer and pass an electrical current and yank the hair out. And you go on doing this for each hair on your body- only for a $100. I am not sure if anyone of these vendors has ever had their pubic hair pulled with a tweezer but it is uncomfortable to say the least.
If it take a few seconds to pull out each hair, jut imagine how long it would take the hair out of the groin or the leg, and how would one take the hair out of the armpit or the back? How does one person remove hair from the back of the neck?
Most likely by the time you have finished with the leg, the hair on the chest have probably grown back.
In essence, all these machines do very little. Because of the low voltages, the machines do not generate enough energy to do much except give you a zing zang feeling. The hair is simply removed with a tweezer except that here you get the pleasure of a small amount of electrical current (if there is any generated?)
All the devices claim that they can pull out hair painlessly? There is no such thing. Hair removal is painful no matter how it is done- there is no painless method to remove hair except perhaps shaving.
These data on the effective of these devices is questionable.
If you want hair removed permanently, go and discuss the subject with a reputable dermatologist and talk to people who have had hair removed. Be informed and then decide.