Zantac is the brand name for ranitidine, a medication used to treat acid reflux, ulcers, heartburn and other disorders of the digestive system. It is a prescription medication, but a weaker version of the drug is available over the counter. The drug is not approved as a means of weight loss, so taking it for that reason is not recommended unless under a doctor's advice.
Consider your eating habits. The reason Zantac is rumored to fuel weight loss is because of its apparent ability to make you feel full. If you eat even when you feel full, such an effect would likely have no bearing on your weight.
Talk to your doctor. Though it is unlikely you will receive Zantac for weight loss, your doctor can prescribe the drug for reasons other than those on the label. According to the Food and Drug Administration, Zantac is for the treatment of ulcers, acid reflux, bleeding in the upper stomach and stomach damage from other drugs.
Consider a substitute. Fiber has been proven to do exactly the thing Zantac is rumored to do: it makes you feel full, and it doesn't require a prescription or even a trip to the pharmacy. Foods rich in fiber include many fruits, grains, vegetables and beans.