Most cellphone shielding products are designed to reduce radiation to the user while still allowing the phone to function. This means that some radiation can still get to the phone… and some radiation can still get out of the phone! But sometimes you need to completely kill the signal. The RF Kill Box is a full-metal shielding jacket with very high shielding performance.

The ultra thin (1mm) RadiCushion by Cellsafe slips into the cell phone case and redirects radiation away from the face of the phone. It's available in black or white but not recommended for use with aluminum or metallic cell phone cases. Test results show a SAR reduction of 96%. A slightly thicker (2mm) RadiCushion is available for iPad and iPad mini; it adheres to the back of the device and also provides SAR reductions of 96%. Visit their website for more information or watch this independent test which shows an 80% reduction and also compares it to the BlocSock:

There were no biological hypotheses tested in the study. It was therefore only a numbers game. Ignored were mechanisms of disease found in other studies of cell phone radiation effects, including genetic damage, blood-brain barrier leakage, and disrupted intercellular communication. The study did not discuss any research supporting the notion that cell phones could cause problems in users.
The use of "hands-free" was not recommended by the British Consumers' Association in a statement in November 2000, as they believed that exposure was increased.[41] However, measurements for the (then) UK Department of Trade and Industry[42] and others for the French Agence française de sécurité sanitaire environnementale [fr][43] showed substantial reductions. In 2005, Professor Lawrie Challis and others said clipping a ferrite bead onto hands-free kits stops the radio waves travelling up the wire and into the head.[44]
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.
More often power off your phone or set it to airplane mode with Wi-Fi OFF and Bluetooth OFF. Even in standby mode, your phone emits RF energy because it is constantly searching for service or new messages. If you do not need your cell phone, simply power it off. This also applies to all other wireless devices whereby the Wi-Fi antennas can be powered off. Wi-Fi enabled laptops, tablets and other wireless devices (such as gaming devices) are always transmitting even if you are not using them, so remember to power them off.

Remember: The cancer incidence data in humans, at least to date, suggests no avalanche of head and neck tumors. Since so many people are exposed to cellphones, if there were a big risk, we’d probably see it turn up. “If cellphones caused brain tumors at the rate that cigarettes caused lung cancer,” said Otis Brawley of the American Cancer Society, “we would have figured it out by now.”

The guidelines, issued last week, note that “some laboratory experiments and human health studies have suggested the possibility that long-term, high use of cell phones may be linked to certain types of cancer and other health effects.” These include brain cancer, tumors of the acoustic nerve and salivary glands, lower sperm count, headaches and effects on learning, memory, hearing, behavior and sleep.
As far as which of those match your device, that really depends on your carrier. AT&T, Verizon, Sprint, and T-Mobile all have different frequencies. To further complicate things, in one geographic region of the country they may use one frequency, while another is used elsewhere. It all depends on which FCC licenses they have the rights to in each region.
INTEGRITY: Many manufactures claim near 100% EMF protection, referring to the radiation blocking material, NOT the protection you receive on a call. If you covered your whole phone with EMF blocking material, then you'd have no signal. Our EMF blocking material is used on the front cover only, providing you real EMF protection with no sacrifice in reception.
The Working Group indicated that, although the human studies were susceptible to bias, the findings could not be dismissed as reflecting bias alone, and that a causal interpretation could not be excluded. The Working Group noted that any interpretation of the evidence should also consider that the observed associations could reflect chance, bias, or confounding rather than an underlying causal effect. In addition, the Working Group stated that the investigation of risk of cancer of the brain associated with cell phone use poses complex methodologic challenges in the conduct of the research and in the analysis and interpretation of findings.
Current regulatory standards (SAR Test) only protect us from thermal or heating risks; yet, many hundreds of laboratory studies have found that low-intensity, non-thermal exposure to cell phone radiation can promote carcinogenic mechanisms. Moreover, research on humans has found that 25 years of mobile phone use is associated with a three-fold risk of brain cancer.  –Joel M. Moskowitz, Ph.D. School of Public Health. University of California, Berkeley
Generally, the Ministry of Health adopts the instructions of most international entities, recommending to follow the “precautionary principle” regarding mobile phone use. The instructions of the Ministry take into account the technological need of the population in Israel, along with the measure of precaution necessary according to the recent scientific information in order to balance between the population’s needs and the preservation of its health.

Researchers need funding to move fast to study the potential health effects of 5G networks and how they might change our exposures to radiation. “So far, we’ve got research that’s done on 3G and 4G but not 5G,” said Brawley of the American Cancer Society. “We do think the answers [about cell radiation’s cancer effects] for 5G may be different from the answers for 4G or 3G. ... As these types of radio waves and energy change over time, the answers [about their health effects] may change.”
Peer review is a vital part of any scientific study; it brings several more lifetimes of expertise into the room to rigorously check a study for any weak points. Melnick calls the peer reviewers’ choice to change some conclusions an unusual move; “It’s quite uncommon that the peer review panel changes the final determination,” he says, noting if anything, he’s seen peer reviewers downgrade findings, not upgrade them. “Typically when NTP presents their findings, the peer review almost in all cases goes along with that.” In this case, the peer reviewers felt the data—when combined with their knowledge of the cancers and with the study design itself—was significant enough to upgrade several of the findings.
To find out about the state of research on the link between phones and cancer, we spoke with Jonathan Samet, dean of the Colorado School of Public Health and an expert in phone radiation who led a World Health Organization working group on the subject. In 2011, the WHO group deemed phone radiation “possibly carcinogenic,” which is less certain than other classifications, but isn’t an outright “no” either. Six years later, Samet said the evidence in either direction is still mixed and that for the time being, there remains “some indication” of risk.

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).