Are the buttocks, under arms, and inner thighs less responsive to Ultherapy than the abdomen is?

results depend on how loose the skin is in the area. some areas need collagen production with sculptra or external radiofrequency as well. sometimes loose skin just needs to be surgically removed or combined with threams and thermage.  See an expert.  Best, Dr. Emer.

We have seen some good results with Ultherapy on the buttocks.  Compared to the abdomen the buttocks seem to need the deeper treatment Ultherapy (4.5mm depth) for lift.  Arms will respond with improvement in the skin texture with a shallower treatment (3.0 or 1.5mm).  Inner thighs may need all three.  There is great variation in patients and in areas of the body as well as many options in depth and density of treatment.  This is certainly not one size fits all so the best approach would be to reconsult your provider and see if a different approach may be needed.

Dear muoldbidy:
What a great question! Ultherapy will work anywhere that the muscle fascia is no deeper than 4.5 mm under the skin. So the answer to your question depends upon how much fat overlies your muscle in those areas. Most people can have the upper inner arms treated as well as the inner thighs (and let’s not forget the area above the knees!)  but success in the buttock area would depend upon where you wish to have the treatment and how thick the fat layer is in that area. An examination should determine this, and if there is any question, the ultrasonic transducers can be placed on the skin to observe the depth of the fascia, to be certain.
All the best,  Dr Clark

Results will vary markedly between individuals. The most predictive value of how well you will go with Ultherapy and the success rate will depend on candidate selection as well as the amount of 'lines' or shots delivered in that area. All these areas are off label but results can be achieved in the right candidate, in addition to using the correct transducer depth (most often the deepest 4.5 mm one) especially for body areas. All the best, The Fiori Institute, Brisbane. Australia. 

Different part of body has different distribution and composition of fat and collagen and skin area.
So different Ultherapy cartridges need to be used to stimulate collagen in different depth of the skin. And the more surface area there is, needs more treatment time. Some areas need more treatments.