During the years 1996-1999, due to the sharp increase in mobile phone use, several expert committees convened worldwide to discuss the question whether the radiowave radiation that is emitted from the mobile phone is harmful to health. Their conclusion was that existing scientific knowledge is insufficient to determine the existence or absence of harm to health.
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!"

Specifically, we looked for studies that measured rates of acoustic neuromas, gliomas, meningiomas, and thyroid cancers. We also narrowed our search to studies that looked at the effect of radio-frequency radiation originating from an actual cellphone, rather than experimental equipment. We did this because we wanted evidence that could apply to real life, not specific laboratory settings or hypothetical outcomes.

Jump up ^ For example, Finland "Radiation and Nuclear Safety Authority: Children's mobile phone use should be limited". Finnish Radiation and Nuclear Safety Authority (STUK). 7 January 2009. Archived from the original on 11 January 2010. Retrieved 20 January 2010. and France "Téléphone mobile, DAS et santé" [Mobile telephones, SAR and health] (PDF). Votre enfant et le téléphone mobile [Your child and mobile telephony]. Association Française des Opérateurs Mobiles (AFOM)[French Mobile Phone Operators' Association] et l’Union Nationale des Associations Familiales (UNAF) [National Federation of Family Associations]. 31 January 2007. Retrieved 20 January 2010.
No special wiring or installation is required. Phone includes volume control, speed dial, redial, speakerphone and hold features. Now with caller ID feature as well! Does NOT have answering machine. Phone can also be used in normal fashion by those not affected by EMF. Color is black, phone color and styles may vary. The phone itself does not have any special shielding nor EMF reduction technology. The whole benefit is that it has the jack for the special air tube headset.
Limit your (and your children’s) cell phone use. This is one of the most obvious ways to limit your exposure to RF waves from cell phones. You may want to use your cell phone only for shorter conversations, or use it only when a conventional phone is not available. Parents who are concerned about their children’s exposure can limit how much time they spend on the phone.
Another way to think about the situation is to consider the steady state power emission of .02 Watts and ask how long it would take to heat up your body by one degree Celsius if your entire volume was exposed. Take your body mass to be 100 kg and approximate it as being composed entirely of entirely of water. If all of the radiation was absorbed and went into heating you up (which it isn’t), it would take 20900000 seconds (specific heat*mass*1 degree/power) or 241 days to heat you up by one degree. Fortunately, you have metabolic processes in your body, or possibly air conditioning, to mitigate this heating.
Well, either the sleeve blocks 99.9% of all emissions or it doesn’t. The point is, anything less than what the company is advertising constitutes FRAUD. If they had said a 50% reduction would be seen, then the RF meter should have reflected that. Methinks that this company is duping a lot of customers. While the product ‘looks’ good, my experience was that it made NO difference at all. In fact, it was worse having this case and the notion of false security. I ended up getting horrific migraines right after I started using it. I was falsely confident that I was being protected. Perhaps part of the case blocked the signal which forced the phone to work that much harder, therefore nullifying any benefit. Please note, consumers. I would not recommend SafeSleeve based on my experience.
“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.”
Don’t be mislead by a common misconception started in the 90′s that wired headsets, that the headset that came with your cell phone is a safe alternative to placing a phone to your head.   This is simply not true at all! Ordinary headsets use a wire to deliver sound to an electronic earpiece that can deliver electromagnetic radiation into your head directly through your ear canal.

In June, at a meeting of scientific counselors to the toxicology agency, Donald Stump, one of the members, worried that the study “will be vulnerable to criticism that it was conducted using outdated technology.” The challenge, he added, is how to move forward with experiments that are large enough to be significant yet nimble enough to keep pace with the rapidly evolving devices.

What the study showed: Self-reported cell phone use was not associated with an increased risk of glioma, meningioma, or non-central nervous system tumors. Although the original published findings reported an association with an increased risk of acoustic neuroma (14), this association disappeared after additional years of follow-up of the cohort (15).