Both procedures have an FDA thumbs up - meaning when the procedure is performed according to the guidelines, it is safe and has demonstrated clinically-documented results. But each patient will respond differently, so the same treatment undergone by two 48 year old patients may give decidedly different results.There is never a 100% guarantee of zero risk of a possible adverse outcome and these are typically listed in permission forms and discussed prior to treatment. Training and experience will always make a difference, so don't make decisions based solely on price. Basic differences: Thermage is designed to tighten skin tissue and uses radio frequency to generate heat. Ultherapy goes deeper to tighten the SMAS layer (and is FDA approved to actually "lift") and uses focused ultrasound.As to skin cancer relationship - skin cancer is a result of sun exposure and neither Thermage nor Ultherapy produce UV light.Since you're dealing with skin, choose a board certified dermatologist or plastic surgeon - either will have a unique understanding of skin. Query the practice about the training levels of the technicians. And ask to see their patient results. ALTERNATIVES: If technology seems too much of a risk, a really good skin care program can keep your skin looking more youthful and consistent sun protection will help preserve the collagen and elastin in your skin as well. Plus, you can get a lift effect with fillers and neurotoxins that can sometimes negate the effects of volume loss and irregular facial contouring that make anyone look more aged.