I am getting Juvederm lip filler. I've been told that sun bed use will mean the filler breaks down quicker. Is this true?

Thank you for your question.  I would strongly recommend against any form of sun bed use, or sun tanning in general for that matter.  Sunlight and sun beds expose our skin to harmful ultraviolet (UV) radiation.  In addition to increasing our risk of skin cancer, UV exposure also rapidly accelerates aging-related changes in the skin, such as fine lines, wrinkles, sagging, dark spots, and uneven skin tone & texture.  
It is also quite possible that excess UV exposure from sun beds/tanning may impact the longevity of your lip filler.  Products like Juvederm are made from hyaluronic acid (HA), a sugar compound naturally found throughout the body.  Our bodies also naturally produce an enzyme, hyaluronidase, which breaks down HA.  Dermatologists and plastic surgeons actually use injectable hyaluronidase to break down unwanted fillers when needed.  Scientific studies have shown that UV exposure actually reduces HA in the skin, and increases hyaluronidase production by skin cells as well - in theory, this could also accelerate the breakdown of Juvederm, although this hasn't specifically been studied.    

Thank you for such an interesting question. There is no clinical evidence to suggest that UV rays will accelerate the breakdown of hyaluronic acid dermal filler. Although, as many other practitioners have also advised, UV rays can cause premature skin ageing and more serious conditions including skin cancer. I travel to the Caribbean to offer facial aesthetics and have not found that sun exposure reduces the length of time that my procedures last. Exercise and increased metabolism will have far greater an effect on the treatment's lifespan.