What is the most effective nonsurgical alternative to a facelift?

Hi there! Thank you for the question.
Re-volumisation using hyaluronic acid based dermal fillers are great when addressing volume loss and hollowness without the need of a scalpel. Using appropriate techniques, dermal filler can be used to help treat the underlying features of an aged face leaving a natural looking and refreshed appearance helping turn the clock back. Personally I use the Juvederm vycross range with excellent results. 
I hope this helps and good luck!

A combination of fillers for volume restoration and non surgical tightening like Ultherapy would help.  There are a number of other skin tightening treatments that may help but the results are not comparable to surgery.