If you've ever caught yourself scrutinizing your knees in the mirror and wondering when they started looking like that, you're not imagining things. The skin above the knees is hyper-mobile and gets crepey with age, and unfortunately, it’s a notoriously difficult area to treat. However, Merz Aesthetics just announced that the FDA has cleared Ultherapy PRIME to improve the appearance of skin laxity on the knees, making it the first and only energy-based aesthetic device indicated for this tricky area.
Why the Knees Are So Hard to Treat
Ask anyone who's tried to address knee laxity and they'll tell you it's one of the more stubborn areas of the body to improve. “The knees are constantly bending and stretching, and the skin in this area is naturally thin,” explains New York facial plastic surgeon Jennifer Levine, MD. “As collagen declines with age, that repetitive motion makes laxity more noticeable."
So when does knee laxity actually start showing up? Earlier than you might expect. “Most people begin noticing knee laxity in their 30s or 40s, although genetics, sun exposure, weight fluctuations and skin quality all influence when it appears,” says Dr. Levine. And if you've been avoiding your workouts out of fear that squats and lunges are making things worse, you can put that theory to rest. “Exercise isn't the problem,” she notes. "In fact, maintaining muscle tone helps support the legs. Aging and collagen loss are the real drivers.” That's where Ultherapy PRIME comes in.
How Ultherapy PRIME Actually Works
Dr. Levine says that until recently, there have been very few nonsurgical options that could effectively target the deeper structural support of the skin. “Ultherapy PRIME stimulates your body's own collagen production using focused ultrasound delivered with real-time visualization, allowing us to treat with precision,” she explains. “Most patients only need one treatment, with results developing gradually over several months. It's well tolerated, and the ideal candidate is someone with mild to moderate skin laxity looking for a natural, nonsurgical improvement.”
With this FDA clearance, Ultherapy PRIME now addresses skin laxity from the brow down to the knees. "Being the first to bring FDA-cleared real-time visualization to the knees represents a meaningful milestone," says Patrick Urban, president of Merz Aesthetics North America. "This launch is about more than a new indication; it's about expanding the addressable market for noninvasive lifting and firming. Body aesthetics is no longer a secondary treatment category."
Dr. Levine agrees: “Patients are no longer treating just the face. They're looking at aging holistically, and the knees have become an important part of that conversation. The future of aesthetics is natural collagen stimulation that improves skin quality while preserving what makes you look like you.”

















