Dear "Guru": If you provide an e-address I can send you copies of a couple of studies done by docs with very good reputations testing the 1064 wavelength against diodes, Alexandrites and IPLs. Generally, the results have been fairly close in terms of percentage of permanent hair reduction, etc. Parameter setttings are of paramount inportance -- so you would have to carefully check the settings used in these studies as well.

The Yag is not the best laser for hair removal on skin types I-III because there are better lasers to use that will do the job more effectively. The Yag's chromophore is hemoglobin, not hair follicles. Much of the energy is absorbed by the hemoglobin before it is absorbed by the melanin in the hair follicle. The Diode has the right wavelength as well as the chromophore being the melanin in the hair follicle, so it is more effective for the FP I-III's.

I'm confused with the last post - here is one of the many examples of how different wavelengths are absorbed by different chromophores:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2825126/figure/F0001/

According to such charts, at 1064 nm melanin still absorbs more energy than hemoglobin, even though the difference in absorption is not as drastic as at 755 nm as for alexandrite or 800-900 nm range, asfor diodes. Otherwise it would also not make sense that KPT Nd:yag lasers (at 532 nm) and not "normal" 1064 nm Nd:yag lasers are used for leg vein treatment (targeting hemoglobin specifically - at that wavelength the absorption is almost identical).

What's more - the absorption by melanin is strictly a function of wavelengh. The same type of laser (Nd:yag in this case) used on types IV-VI and yielding great results, would be absorbed in a similar way in types I-III, right? Again, given smaller amounts of melanine in types I-III, higher-fluence impulses can be used and, where the laser was effective on darker skin, it would potentially be even more effective in damaging hair follicles in lighter skin...

Is my logic flawed?

Hello,

I am currently contemplating purchasing an aesthetic laser, with about 90% of its capacity to be used for hair removal. I'm very much leaning toward a specific manufacturer (Fotona, having heard fantastic reviews of their machines) and a specific laser type (1064 nm. Nd:yag, with 532 nm. KPT attachment for vein treatment). This site has been a tremendous help in getting opinions of unbiased professionals who have a lot of practical experience with actually using these machines, as opposed to just hearing out sales reps, who give you a lot of theory, which may not always work. I am, therefore, asking for your help in trying to understand something related to practial application of Nd:yag lasers for hair removal:

I've been reading the blogs on this resource for quite a while and one - almost unanimous - comment regarding the use of Nd:yag machines for hair removal was that it is just great on skin types III-VI. At the same time, a vast majority of professionals on this site confessed (and it seems to be a de-facto protocol out there, too) that they are using alexandrite lasers for skin types I-III and Nd:yag lasers for skin types III-VI.

While I understand that alexandrite may not be suitable for types IV-VI due to succeptibility of these skin types to burns, because of high melanine levels and consequent absorption of laser energy by skin, rather than by hair follicle, I do not understand why most professionals do not use Nd:yag lasers for skin types I-III. After all, the theory behind Nd:yag 1064 nm. hair removal is that it is safe on ALL types of skin (not just III-VI) AND (more importantly) it penetrates deeper (up to 4 mm) and, thus, may potentially destroy the follicles that are not reached by alex or diode lasers. While I understand that safety does not equal effectiveness and Nd:yag may simply be the best AVAILABLE option for skin types IV-VI, given that the use of other lasers is quite limited on these skin types and, most of the time, just downright dangerous - I am still struggling to understand why the same people who swear by great results obtained with Nd:yag lasers do not use it for types I-III. After all, my understanding is that if hair is effectively removed on darker skin types, where the fluences used still have to be watched - wouldn't it be at least equally effective on ligher skin, where, potentially, higher fluences may be used?

This is an important consideration for me, because there are combos out there, that have alex and Nd:yag lasers in one device, but I'm just not convinced that this is strictly necessary. So, my question is - has anyone had any experience using Nd:yag laser hair removal machines on ligher skin types and can anyone comment on how they compare to other lasers used for the same skin types? Is it at all possible to obtain good results with skin types I-III using just a good Nd:yag laser?

As always, your advice is greatly appreciated.

Guru
You indeed can yse an ND-Yag on skin types i-iii . It may not be a quick or efficent as an alexandrite but will work. The problem is chromophore absorption. The alex is much more semsitive to pigment. The YAG is less in fact its not very sensitive to much whn you look at the charts. I believe one of the concerns is general discomfort.
In order to get the best results out of the yag you will need a bit more power thus a bit more doscomfort.
The spa that i inject at has been using ND-Yag as their SOLE laser for over 10 years. Essentially its safe for all skin types.
I cant say for sure but this may be a part of why its fallen out of favor in types i-iii but certainly can be used.