What is the maximum frequency which is safe for hair laser?

Hello there, 
        LHR differs from provider to provider, from laser to laser, and from patient to patient. With your coloring, lower setting will definitely always be best utilized, but that does not mean that increasing the intensity slightly will cause issues. Typically LHR settings DO have to be increased from appointment to appointment since the hair gets thinner and harder to treat effectively with the same setting. If you have concerns, I would definitely discuss with your provider. Hope this helps.
-Sarah RN BSN 

Laser hair removal works on the principle of customizing the laser energy to match your skin type, and hair type. So, yes, it is okay to go up on the energy  to improve the results. For example, it is okay to use more than one mode, more than one wavelength, mix up the wavelengths, use different energies in different parts of the body and so on. The visual cue for the optimum energy in each session, is an end point - which can be follicular edema (swelling around the hair roots), to visible hair extrusion, to follicular erythema (redness). The end point is dependant on the device and the energy used. So yes, the energies will not be the same during each visit, and each visit would only be able to give you 10-20% reduction. More is possible and happens during the first few sessions, if the hair is very thick, but it is best to keep your expectations realistic.