How long does the effect of Sculptra last?

I met a friend yesterday who got fillers a month ago, and she definitely looked smaller and younger because her face had more volume. However, I'm a bit scared to get fillers on such a large area... I'm still worried because the posts I read about fillers shifting or potential side effects have stuck in my mind for so long. I heard that Sculptra, a procedure that adds volume like fillers but stimulates the body to generate its own collagen so that the skin naturally plumps up, feels natural without any foreign body sensation. However, I've heard that immediate results like fillers are difficult to achieve. I've heard you have to wait about 2 to 3 months; is that really true? Also, since the skin is filled with newly created collagen, I'm wondering if the volume might decrease if the patient changes their lifestyle or loses weight. It seems like a procedure heavily influenced by external factors, so I'm concerned that the effects might not last long. It would be a shame if the effects appear slowly and then don't last. Please let me know about the duration of Sculptra's effects. Also, if anyone has received Sculptra, it would be helpful if you could share any downsides or any aspects you found disappointing.