Mylanta is a liquid antacid that contains two acid-neutralizing minerals and one gas-relief ingredient. The exact combination varies slightly between product lines, but every version is built around the same basic formula: a mineral compound that neutralizes stomach acid plus simethicone to relieve gas and bloating.
Active Ingredients
Mylanta products contain either two or three active ingredients depending on the formulation. The Mylanta Tonight version, for example, contains 800 mg of calcium carbonate, 270 mg of magnesium hydroxide, and 80 mg of simethicone per 10 mL dose. The Maximum Strength Classic version uses aluminum hydroxide and magnesium hydroxide as its acid-neutralizing pair, also combined with simethicone.
The acid-neutralizing ingredients work through a simple chemical reaction. When the mineral compounds reach your stomach, they directly combine with hydrochloric acid and neutralize it. This raises the pH inside your stomach, which reduces the burning sensation of heartburn and helps protect irritated tissue in the esophagus and stomach lining. Relief typically starts within minutes because the reaction happens on contact.
Simethicone handles a different problem entirely. It doesn’t affect stomach acid at all. Instead, it works by merging the small gas bubbles in your digestive tract into larger ones, making it easier for trapped air to move through and pass out of your body. That’s why Mylanta is marketed for both heartburn and gas pressure, even though those are two separate issues handled by separate ingredients in the same bottle.
Inactive Ingredients
Beyond the active ingredients, Mylanta contains a number of inactive components that give the liquid its texture, flavor, sweetness, and shelf stability. The Vanilla Caramel flavor of Mylanta Maximum Strength lists: benzyl alcohol, caramel, carboxymethylcellulose sodium, flavors, glycerin, microcrystalline cellulose, purified water, sodium carbonate, sorbitol, sucralose, and xanthan gum.
A few of these are worth noting. Sorbitol is a sugar alcohol that can cause digestive discomfort in people who are sensitive to it, especially in larger amounts. Sucralose is an artificial sweetener. Benzyl alcohol serves as a preservative. The Mylanta Tonight formulation also includes sucrose (regular sugar) in addition to sucralose. If you’re watching your sugar intake or have sensitivities to sugar alcohols, these are the ingredients to pay attention to on the label.
How the Formulations Differ
The key difference between Mylanta products is which minerals do the acid-neutralizing work. Some versions pair aluminum hydroxide with magnesium hydroxide. Others, like Mylanta Tonight, swap out the aluminum for calcium carbonate while keeping the magnesium hydroxide. The simethicone component stays consistent across formulations.
This distinction matters because aluminum and magnesium have opposite effects on your bowels. Aluminum tends to cause constipation, while magnesium tends to cause loose stools. When they’re combined in the same product, those effects roughly cancel each other out. In formulations that use calcium carbonate instead of aluminum, the balance shifts slightly, since calcium carbonate can also lean toward constipation.
Drug Interactions to Know About
The minerals in Mylanta can interfere with how your body absorbs certain medications. The metal ions in aluminum, magnesium, and calcium can bind to other drugs in your stomach and form compounds your body can’t absorb, effectively reducing or blocking the medication’s effect.
Two classes of antibiotics are particularly affected: tetracyclines and fluoroquinolones. If you take Mylanta too close to a dose of either, the antibiotic may not reach effective levels in your bloodstream. The standard recommendation is to take antacids either four hours before or two hours after these antibiotics. Osteoporosis medications called bisphosphonates carry the same warning in their prescribing information, though the interaction hasn’t been formally measured.
Safety Limits and Risks
For Mylanta Maximum Strength, the labeled limit is 60 mL (six doses) in any 24-hour period. Staying within this range is straightforward for occasional use, but problems can develop with regular, prolonged use or in people with kidney issues.
Your kidneys are responsible for clearing excess magnesium from your blood. If your kidney function is reduced, magnesium from Mylanta can build up and potentially reach toxic levels. Magnesium toxicity affects the nervous system and heart, causing muscle weakness, dangerously low blood pressure, and in severe cases, slowed breathing. For formulations containing aluminum, long-term use in people with kidney problems can also lead to weakened bones and low phosphorus levels. If you have any degree of kidney disease, aluminum-free and magnesium-free antacid options are generally safer choices.
For people with healthy kidneys using Mylanta occasionally for heartburn or gas, these risks are minimal. The ingredients clear your system efficiently and the doses per serving are well within safe ranges for short-term use.