If you cut salt for just a week or two, your blood pressure doesn’t drop as much as it will if you keep it low for a month or more—it takes time for the full effect to show up.

Cutting back on salt helps lower blood pressure, and this works just as well whether you do it for a few weeks or up to a year—only a tiny bit less after a long time.

Cutting back on salt for just one week lowers blood pressure by about 8 points in most people over 50, even if they’re already taking blood pressure medicine — and it works just as well whether they have high blood pressure or not.

If you have high blood pressure and cut down on salt from a lot to very little, your top blood pressure number might drop by about 7 to 9 points — and the higher your blood pressure was to start with, the more it drops.

Even if your blood pressure is normal, cutting back on salt still helps lower it a little—which could help prevent high blood pressure as you get older.

Different studies say reducing salt lowers blood pressure by wildly different amounts—some say almost nothing, others say a bit more—so we’re really not sure how much of an effect salt really has.