No herb or vitamin will cause significant amounts of weight loss by itself -- for this you need a balanced, reduced-calorie diet and exercise plan. Vitamins are most likely to help with weight loss if they are used to correct a deficiency. Check with your doctor before taking supplemental herbs or vitamins to avoid side effects.
Vitamins and Weight Loss
Although proponents claim that vitamin B-12 injections may be helpful for weight loss by increasing your energy levels, the only proven benefit for these shots is to treat vitamin B-12 deficiency and pernicious anemia.
Increasing your vitamin C intake may be beneficial for weight loss if you're deficient in this vitamin. People with sufficient vitamin C tend to burn more fat, according to an article published in the Journal of the American College of Nutrition in June 2005. It isn't likely to be helpful if you already get enough vitamin C in your diet, however.
Likewise, people who have sufficient stores of vitamin D tend to lose more weight than those who are deficient in vitamin D, according to a study published in the American Journal of Clinical Nutrition in March 2014.
Herbs and Weight Loss
According to the Cleveland Clinic, herbal weight-loss products won't help you lose weight permanently. Most of these products either have a diuretic or laxative effect, act as a stimulant or increase levels of a chemical called serotonin that helps you feel full. Herbs with a diuretic or laxative effect include dandelion, guarana, aloe and cascara. These herbs may cause water-weight loss, but not fat loss. Guarana and yerba mate contain caffeine and act as stimulants, theoretically causing a small, temporary increase in metabolism. Dandelions may also slow the digestion of your food so you don't get hungry as quickly after eating, according to an article on the CNN website.
The herbs commonly used for weight-loss purposes can cause side effects. Yerba mate may increase the risk for high blood pressure and certain types of cancer. Guarana may interact with blood thinners and cause anxiety, dizziness, high blood pressure and nausea. Some people are allergic to dandelion. Cascara may interact with diuretics and digoxin. Aloe may cause diarrhea, cramping, decreased potassium levels and electrolyte imbalances. Caffeine-containing herbs can cause insomnia, restlessness, headaches and anxiety.
High levels of vitamin C may cause diarrhea and headaches and might increase your risk for kidney stones, and excessive vitamin D intake can cause diarrhea, appetite loss, vomiting, weakness and kidney failure.
A Healthier Weight-Loss Plan
If you want to lose weight in a healthy manner, cut 500 to 1,000 calories from your diet each day to lose 1 to 2 pounds per week. Eat more foods that are low in energy density, or calories per gram, such as vegetables, fruits, whole grains and lean meats, and limit your intake of processed foods and foods high in fat and calories. Eating a broth-based soup or salad before each meal can help fill you up and make it easier to eat less of the higher-calorie entree foods on your plate. Adding more exercise to your daily routine will help you further increase your weight-loss results.