After you lose weight or deliver a baby the skin shrinks to some degree but that is limited. If the excess amount of skin is too great it just cannot shrink that much on its own. In my experience it takes about 6 months after the weight loss or delivery to see how much the skin is capable of shrinking. I have not been impressed with the lasers and radiofrequency devices used to shrink skin. The excess can always be removed by abdominoplasty etc. but that requires an incision and always leaves some sort of scar.
Can You Lose Excess Skin from Pregnancy or Weight Loss?
Doctor Answers 2
Shrinking skin and stretchmarks
Can you lose excess skin from pregnancy?
Exercise can certainly help to tone a region. If skin tightening is achieved, it would only be modest. Lasers have been touted to tighten loose skin. However, in my experience, these claims sound better than they perform. Sometimes excision (such as tummy tuck or arm lift) are the best option. I look at skin like the elastic the waistband of sweat pants or underwear. If it has lost its elasticity, it will never return.