Page 44 - Mike Murphy's Blog Posts

We can see that many hairs, in fact 40%, are killed at this point – that’s because, at week 0, 40% of all the follicles were in the anagen phase. Note that this assumes that the laser/IPL has been set up correctly with the most appropriate wavelength(s), fluence and pulsewidth.
It becomes immediately obvious that the next “best” time to treat this site again is 8 weeks after the first treatments because this is when ALL the follicles are back in anagen phase again! Any treatment done before this time will not hit all the follicles, since many will be in either catagen or telogen phase.
It is immediately obvious that ALL the follicles are now dead!!!! After only two sessions! No further treatments are required...
So, the above example clearly shows that the OPTIMUM time to treat this area again depends entirely on emergence of all the follicles on the anagen phase. If these are treated again at week 14, then they will ALL die! This means that arm pit hair follicles can be fully destroyed in only two treatment sessions – but ONLY if the correct laser/IPL parameters are used.
This is where the ‘real world’ problems lie – most operators do not use the correct parameters. There are at least three reasons why this is the case:
1) They have not been properly trained and do not understand what they are trying to do;
2) They do not apply the correct parameters, instead using too low a fluence, or too short a pulsewidth;
3) Their equipment cannot generate the correct parameters in the first place (this occurs far too frequently).
Mike’s Blog Posts 44