It’s easy to call any case a product designed to block smartphone radiation.  What you need to look for is credible, quantifiable claims that highlight a case’s ability to reduce your exposure to the harmful radiation. Look for relevant  certifications from credible organizations (such as FCC accredited laboratories) that will vouch for product claims, and read product reviews online.
It’s true that cellphones do emit radiation. And radiation is a scary word for a lot of people, thanks in part to the horrific aftermath of nuclear accidents and photographs of victims of the nuclear bombs the US dropped on Japan in World War II. People hear radiation and they associate it with nuclear radiation and the bomb, says Geoffrey Kabat, a cancer epidemiologist at the Albert Einstein College of Medicine and author of the book Getting Risk Right. “There are all these associations and those are deeply ingrained in people. But it doesn’t apply here.”
Four years ago -- before I bought my first iPhone -- I wouldn’t buy certain model cell phones because their radiation emission levels were too high. I became obsessed with researching this in the buying process, especially after finding out that a man I knew died of brain cancer and was an early mobile phone user. Suspicion was that the phone caused the cancer.
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.
Exposure to ionizing radiation, such as from x-rays, is known to increase the risk of cancer. However, although many studies have examined the potential health effects of non-ionizing radiation from radar, microwave ovens, cell phones, and other sources, there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans (2).