How many sessions of IPL will it take for my rosacea to improve?

Thanks for the question,I actually posted a editorial on this topic and perhaps you may find it usefull. I'll add a link below. James P. Bonaparte, MD, MSc, FRCSCJB Cosmetics and Facial Surgery Center of OttawaHead and Neck Surgerypracticing in Facial Plastic and Reconstructive SurgeryAssistant Professor, University of OttawaOttawa, Ontario, Canada

Broadband Light (BBL) or Intense pulsed Light (IPL) treatments work by throwing all the wavelengths of visible light at a target, in this case hemoglobin (more accurately oxyhemoglobin, or oxygenated blood). Unfortunately, in addition the the desired wavelength of light needed to be absorbed by those unwanted vessels to seal them, you also have all of the unwanted energy just going into the skin as heat, which can cause blistering and in rare cases, scarring. So, the energy of IPL or BBL treatments has to be carefully minimized so that you get "enough" energy to treat the unwanted vessels, but not so much to cause burns,  blisters, or scars. Finding that "just enough" but "no too much" is something you read about here on RealSelf all the time! And that is why multiple treatments are usually necessary. Safety is good, but let's not "soak" the patients for recommending a suboptimal treatment, just because that is what your doctor has available.Wavelength-specific treatment  is better rendered by a pulsed dye laser, operating at a wavelength of 577-585nm (yellow), which happens to coincide with a significant beta-absorption peak in the oxyhemoglobin absorption curve. What that means is that the majority of the treatment energy is absorbed only by the unwanted vessels (treatment depth at the proper energy utilized is no more than 1/2 to 1 mm, so the "normal, needed" vessels deeper are left undamaged) that you want gone, and very little collateral skin damage occurs. Virtually no blistering should occur with a proper-energy treatment by an expert in pulsed dye laser treatments. These are the same lasers used to treat port-wine stain birthmarks (congenital capillary malformations) in children, so they are safe. And effective. Usually with ONE treatment.Here is the not-insignificant downside. This laser works by putting a significant amount of energy at the right wavelength and proper pulse duration (about 450 microseconds, or half of a thousandth of a second) into the target (vessels), heating the vessels to rupture (they're tiny dilated capillaries, remember), and then "turning off" (the short pulse duration) before thermal damage occurs elsewhere.The ruptured vessels are effectively destroyed, most in one treatment, but in their destruction they leave a blue-black bruise just under the skin surface (like a massive black eye, but in the areas treated). This severe bruise is severe enough that "standard" makeup can't cover it. But the single treatment results are worth it, IMHO. V-beam treatment at the same wavelength offers slightly more energy, slightly higher risk of blistering, but slightly less bruising. Not a good trade-off, IMHO, but still better than IPL.The key is the laser operator, not the machine, but so is choosing the proper machine for the job at hand. Consult several experts, and make sure they recommend what is best (and can tell you why, just as I have striven to do with this answer), not what they "have." Best wishes! Dr. Tholen