How much is too much?

There are too many variables to be able to pinpoint how much is too much but it is clear that the bi-phasic dose response exists in biological systems and, if exceeded, then there are diminishing returns. 

Many research studies have been inconclusive on account of using too high dosing. For superficial tissue (skin), an optimal window for dosing has been established of between 2-10 Joules/cm2 (you can achieve this dose with Maysama's Pulse40 panel over a 6 minute session with pulsed light). For other applications, like pain relief or muscle recovery, higher irradiances will be beneficial to reach deeper tissue. 

The reason for the reduction in efficiency with extended treatments is understood to be due to a build-up of free radicals. At low levels, free radicals act as signaling molecules and trigger biostimulation. But with prolonged LED exposure, an overabundance of free radicals can lead to oxidative stress and cell damage.

Pulse LED light helps to mitigate the build-up of free radicals, allowing your device to work more efficiently for longer. It is also more efficient; increasing ATP output and accelerating cell regeneration, so recommended treatment times can generally be reduced. 

Free radicals have an extremely short life-span - we’re talking milliseconds. This means that, if you have two separate treatment sessions in the same day, you will not be 'overdosing' on red light therapy as free radicals, produced by your red light, will dissipate immediately after your treatment. That said, there is no conclusive benefit for using LED therapy more than once per day.