Which is the best treatment for building collagen: Sculptra or Laser or something else?

There are many ways to build collagen. Sculptra, lasers, RF, Radiesse, Bellafill, all stimulate collagen. It depends on what area and outcome as to what method is used for collagen building. New collagen lasts 7 years. The Sculptra studies were stopped at 2 years, but that doesn't mean that it only has an effect for 2 years. It's effects are long lasting, but there is that problem called aging, that counteracts the collagen produced. That is why touch ups are needed with Sculptra every 12-18 months and why collagen building procedures don't last forever. 

The answer to this question really depends on what your current issues are and what you are trying to achieve. If you have significant loss of facial volume in the hollows of the cheeks, temples or smile lines, Sculptra would be the better option for you. If you do not have major volume loss but you are interested in building collagen to tighten your skin and diminish fine lines and wrinkles, then a collagen building laser, such as 3D, would be your best option. 3D laser combines two lasers (one on a deeper and the other on a more superficial level) to stimulate collagen which in turn tightens skin and reduces the appearance of fine lines and wrinkles. Again, one or both may be for you but it really depends on your problems and goals. I would advise an in-person consultation with a board-certified dermatologist who offers both collagen building laser treatments and Sculptra, to see what the most effective treatment plan would be for you.