The World Health Organization (WHO) says the intensity of radio frequency (RF) radiation from cell phones decreases exponentially the further the device is held away from the body. Therefore your safest bet it keep your cell phone as far away from your ear and body as possible at all times. Don’t carry it in your pocket, tucked into a bra strap, and definitely don’t sleep with it next to your head.
I also searched around to see if cell phone radiation was anything to worry about anyway. I turned up enough information from a lot of different credible sources to convince me it was worth protecting against the possible damaging effects of this radiation. IF there is no real health impact, then having a protective device would be overkill, but I figured better overkill than discover in time people started developing problems as a result of heavy cell phone use.
“If you're looking for ways to limit your exposure to the electromagnetic emissions from your cell phone, know that, according to the FTC, there is no scientific proof that so-called shields significantly reduced exposure from these electromagnetic emissions. In fact, products that block only the earpiece—or another small portion of the phone—are totally ineffective because the entire phone emits electromagnetic waves. What's more, these shields may interfere with the phone's signal, cause it to draw even more power to communicate with the base station, and possibly emit more radiation.”
5. Use an EMF shielding device. A variety of holsters and other cell phone holders and shields are available that claim to block radiation. If you buy such a product, look to see if it has an SAR (specific absorption rate) value. You want a shielding device that blocks the majority of EMFs. (SAR is a measure of the rate at which energy is absorbed by a body exposed to EMFs.)
Anti-radiation or radiation blocking or phone shield cases. Do they Work? SafeSleeve, DefenderShield, Vest, Alara, Pong, Reach and ShieldMe and other EMF protection phone cases claim to block the radiation from your cellphone or smartphone. Anti-radiation cellphone case brands make enticing claims like this: ". . .eliminate up to 99% of the harmful radiation coming from the phone!"
The U.S. government doesn’t seem very troubled, either. The Food and Drug Administration says on its website that research generally doesn’t link cell phones to any health problem. And although the Federal Communications Commission requires manufacturers to include information in user manuals about cell-phone handling, that’s often buried deep in the fine print.
The research continued, and what it uncovered would be a dire warning to cell phone users and the industry’s worst nightmare. When the findings were ready for release in 1998, the scientists were suddenly confronted with another challenge: the industry wanted to take over public dissemination of the information, and it tried everything it could to do so. It was faced with disaster and had a lot to lose.
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.