As a rule, modern medical equipment is well protected against exposure to radiowave radiation. Therefore, there is generally no need for concern regarding the effects of mobile phones on the normal function of the equipment. Nevertheless, the Ministry of Health recommends not to have a mobile phone in the immediate proximity (a distance of 30-50 cm from the portable medical equipment or from medical equipment implanted in the patient's body).
This 2017 review, published in Neurological Sciences, looked at case-control studies on cellphone use, focusing on glioma, meningioma, and acoustic neuromas. This review was interesting because the researchers divided the studies by quality, and higher-quality studies — which tended to be funded by the government and not the cellphone industry — showed a trend toward an increased risk of brain tumors, while lower-quality studies did not. Overall, though, their meta-analysis found an increased risk of brain cancers (mostly gliomas) among people who were using cellphones for 10 or more years, and no increase in the risk of acoustic neuroma.
When you talk, your voice is transmitted from the antenna as radio frequency radiation (RFR) between 800 MHz and 2,200 MHz. A range equal to the middle of microwave frequency and 20% to 80% of the radiation emitted is deposited in the user's head. The microwave radiation is absorbed and penetrates the area around the head, some reaching an inch, to an inch and a half into the brain. Exposure to this microwave RFR has shown to have serious health consequences. Laboratory studies have shown that radiation from cell phones expose the user to a wide range of health problems including: 

Launched at the U.S. Food and Drug Administration’s request 10 years ago, the NTP study dosed rats and mice of both sexes with RF radiation at either 1.5, 3 or 6 watts of radiation per kilogram of body weight, or W/kg. The lowest dose is about the same as the Federal Communications Commission’s limit for public exposure from cell phones, which is 1.6 watts W/kg. The animals were exposed nine hours a day for two years (about the average life span for a rat), and the exposures were cranked up steadily as the animals grew, so the absorbed doses per unit body weight remained constant over time.

I noticed the Blocsock hardly added any bulk to my phone, and fit comfortably in my pocket. I have a Rocketfish RF-MTVT2SP protective gel case and thankfully the phone fits the Blocsock without having to take off this case. The Blocsock is very easy to use, and is quick and easy to take out and answer the phone. Again, if you get one, make sure the size you order is right and not too tight or loose. The pouch on the Blocsock is handy when using the phone to call people so the phone can be placed in the pouch between the Blocsock and me, protecting my head from radiation while still enabling people to clearly hear me and vice versa.
According to the WHO, the "precautionary principle" is "a risk management policy applied in circumstances with a high degree of scientific uncertainty, reflecting the need to take action for a potentially serious risk without awaiting the results of scientific research." Other less stringent recommended approaches are prudent avoidance principle and as low as reasonably practicable. Although all of these are problematic in application, due to the widespread use and economic importance of wireless telecommunication systems in modern civilization, there is an increased popularity of such measures in the general public, though also evidence that such approaches may increase concern.[35] They involve recommendations such as the minimization of cellphone usage, the limitation of use by at-risk population (such as children), the adoption of cellphones and microcells with as low as reasonably practicable levels of radiation, the wider use of hands-free and earphone technologies such as Bluetooth headsets, the adoption of maximal standards of exposure, RF field intensity and distance of base stations antennas from human habitations, and so forth.[citation needed] Overall, public information remains a challenge as various health consequences are evoked in the literature and by the media, putting populations under chronic exposure to potentially worrying information.[36]
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Use a corded home phone whenever possible, to minimize the need for a cell phone. Cordless home phones emit RF, so replace cordless phones with corded home phones. One initial step is to unplug the electrical cord of the cordless phone base station when the phone is not in use, because otherwise that base station will emit RF nonstop. Note: you can plug a corded phone handset or corded headset into your VoIP connection.  
First, you must have a proper meter. To check for magnetic field emissions, an AC Gaussmeter will work. Most AC gaussmeters will have an internal probe. Simply position the gaussmeter on the phone. Note carefully where the meter is positioned. Make a call and watch the readings. Notice the highest and lowest readings, and make a mental note of the "average" reading. Now, insert the magnetic shield, and repeat.
I received mine yesterday in the mail. I have a Samsung Galaxy Note 3, and I cannot use this sock unless I take the case off. This is one thing I did not know when I was purchasing this material. I am trying it out as stated, however even when I use a rubber case or a very thin case with the sock its very tight to get off. I think the manufacturer needs to allow more room in these and or not state that it fits the larger phones at 6 inch. They should state that without the case it will fit. I am in the first day of walking around without a case, and just the sleeve. Its different, and if I drop my phone I'm in a world of hurt. I like the idea of this, but I was also surprised when the material really only feels like felt. It's not like the RF fabric that I have seen, and hopefully this is some kind of special blocking material as stated. I do like the idea, and I agree that cell phone radiation exist. Ill come back and give five stars if I really notice a difference, however if I drop my phone because I dont have a case I'm going to be posting less stars.
This 2017 systematic review and meta-analysis, published in PLOS One, looked at mobile phone use in case-control studies and the risk of glioma. “Our results suggest that long-term mobile phone use may be associated with an increased risk of glioma,” they wrote. The researchers found an association between mobile phone use and low-grade glioma in the people who used cellphones regularly or for 10 years or more. “However, current evidence is of poor quality and limited quantity,” they added, and called for prospective studies to confirm the results.
As Jonathan Samet — the dean of the Colorado School of Public Health, who advised the World Health Organization on cellphone radiation and cancer — told me, you can argue anything based on the science we currently have “because there’s not enough evidence to start with.” Actually, there’s not enough high-quality evidence. Before we get into why, and what we know, we need a quick primer on cellphone radiation.
We are often asked why we don't carry the chips, neutralizers, cutesy bugs, and some other cellphone radiation products that are so heavily marketed on the internet. Our answer is simple and honest: our criteria for including a product in our catalog is that it does what we say it does, and its effectiveness can be demonstrated with an appropriate meter.
The bulk of scientific evidence says that cellphone radiation doesn’t harm humans, according to the Food and Drug Administration: our cellphones are much more likely to kill us when we glance down at them while driving. But people are bad at judging risk. And the word “radiation” combined with the fact that we can’t see or control the invisible forces emanating from our cellphones becomes a perfect recipe for fear.

There is no strong or consistent evidence that mobile phone use increases the risk of getting brain cancer or other head tumors. The United States National Cancer Institute points out that "Radiofrequency energy, unlike ionizing radiation, does not cause DNA damage that can lead to cancer. Its only consistently observed biological effect in humans is tissue heating. In animal studies, it has not been found to cause cancer or to enhance the cancer-causing effects of known chemical carcinogens." The majority of human studies have failed to find a link between cell phone use and cancer. In 2011 a World Health Organization working group classified cell phone use as "possibly carcinogenic to humans". The CDC states that no scientific evidence definitively answers whether cell phone use causes cancer.[5][7][8]
There was also “equivocal” evidence that it raised the risk of heart conditions, and led to evidence of DNA damage. Baby rats born to mothers during the trial had lower birth weights. The scientists also found a statistically significant increase in lymphoma (cancer of the lymph nodes) among female mice and heightened rates of liver cancer in the male mice. All those findings were labeled “equivocal.”
There’s not a lot of research on the effects of cell-phone use on children’s and teens’ health, the report acknowledges, but some studies have suggested that it may be associated with hearing loss, ringing in the ears, headaches and decreased well-being. Children who use cell phones will also have more years of exposure to RF energy over their lifetimes than people who started using them as adults, which leads some doctors to recommend added caution.

The CERENAT study, another case–control study conducted in multiple areas in France from 2004 to 2006 using data collected in face-to-face interviews using standardized questionnaires (18). This study found no association for either gliomas or meningiomas when comparing regular cell phone users with non-users. However, the heaviest users had significantly increased risks of both gliomas and meningiomas.