The answer depends entirely on what kind of results you are asking about.
Immediate results: seconds
The smoothing and shaping effect of shapewear is immediate. The moment you put on a well-fitted shaping garment, you have a smoother silhouette. There is no waiting period it is the direct result of compression on soft tissue.
Postural results: days to weeks
Many women report feeling more upright and supported when wearing shapewear regularly. Over time, the postural awareness can carry over slightly into how you hold yourself without them. This is not a dramatic transformation but it is real.
Post-surgical results: months
After liposuction, a tummy tuck, or a BBL, wearing medical-grade compression garments is part of the recovery protocol. The final results of surgery take 3-6 months to fully emerge, and the compression garment you wear in the first 6-8 weeks directly influences the quality of those results.
What shapewear cannot do over time
Wearing shapewear every day will not permanently change your body shape, redistribute fat, shrink your waist measurement, or build muscle. The compression that creates a smoother silhouette while you are wearing the garment does not continue working after you remove it.
Getting the most from your shapewear
Focus on three things: correct sizing, appropriate compression level for your purpose, and garment quality. The shapewear that gives you the best results is the one you can wear comfortably not the tightest one you can squeeze into.