So far, the only known mechanism that mobile telephone radiation has had an effect on living tissue is heating. The rise in temperature on the surface of the brain caused by radio waves is 0.3 degrees at the most. This kind of temperature rise is not known to have biological significance. The temperature of the brain normally fluctuates by about one degree, and only after a five degree increase in temperature do cells become damaged.

Several studies, in several countries, have tried to find out any other effects apart from heating. On the basis of the results obtained from the studies, it has not been possible to conclude that radiation from mobile phones would be detrimental to health.
Experiments performed on cell cultures, also performed at STUK, have produced indicators that mobile telephone radiation could cause temporary changes in the functions of cells. These functions include the functions of genes, activation of proteins, and the internal chemical communication within cells. The trigger for these changes is unknown. It is only known that this phenomenon is not the result of excessive heating of tissue.
Here in this video, Jyotika Sharma tells us some dos and don'ts of mobile phone use.