This is one of the areas where diet change produces measurable numbers within weeks. It is also the area where the interaction between food, supplements and prescribed medication matters most, so read the cautions properly.
Never stop or reduce blood pressure medication on your own. Never take potassium supplements alongside an ACE inhibitor, an ARB, or spironolactone, or if you have kidney disease, as the combination can raise blood potassium dangerously. Food potassium is a different matter, but ask your pharmacist if you take any of those. Chest pain, sudden severe headache, or one-sided weakness are emergencies.
The week-by-week plan, the foods, the supplements worth taking and the ones to skip. The safety section above stays free, always.