Handsets have been shown to vary enormously in their radiation outputs and health effects appear to be dose dependent. Older models generally pump out more than the newer ones, though this is not always the case. It has been found that up to 60 per cent of the radiation emitted by a mobile handset is absorbed by the user's head. Having an aerial that points away from your head is little, if any, protection. Radiation has been shown to effect changes on a cellular level and include alterations to DNA itself.
More common complaints are increases in headaches, fatigue and possibly skin irritations.
SAR is measured in Watts absorbed per kilogram of body weight. There is still a great deal of research required to confirm or discount these findings. Niels Kuster of the Swiss Federal Institute of Technology tested a number of popular mobile handsets. When compared with the values at which biological changes have been recorded, the outputs of all the phones tested provided reason for concern. However, to be fair, different testing procedures and protocols can yield differing results.