Alkalising products are promoted widely. These include alkaline water, alkalising powders and alkaline diets. Alkaline diets recommend you modify what you eat based on your urine or saliva pH, claiming a more alkaline pH helps digestion, weight loss and well-being.
But your stomach is highly acidic at a pH less than 3.5, with this acid helping breakdown food. It then moves into the small bowel for digestion and absorption where the pH increases to 4.5-5.0, which is still acidic. Your body has finely controlled pH balancing mechanisms to make sure your blood pH stays between 7.35-7.45. If it did not, you would die.
On the positive side, alkaline diets encourage healthier eating by promoting plant based foods such as fruit and vegetables. But there is definitely no evidence that an alkalising product will do your body any benefit.
For more info check this out: https://theconversation.com/five-supplements-that-claim-to-speed-up-weight-loss-and-what-the-science-says-89856.