Mylanta and Maalox are essentially the same product. Both contain identical active ingredients in the same concentrations: aluminum hydroxide, magnesium hydroxide, and simethicone. The standard liquid versions of each brand contain 200 mg aluminum hydroxide, 200 mg magnesium hydroxide, and 20 mg simethicone per 5 ml dose. Even their “extra strength” lines match up perfectly.
Identical Ingredients at Every Strength
At the regular strength level, Mylanta and Maalox each deliver 200 mg of aluminum hydroxide and 200 mg of magnesium hydroxide per teaspoon, plus 20 mg of simethicone for gas relief. The maximum strength versions, sold as Mylanta Maximum Strength and Maalox Advanced, both double those amounts to 400 mg of each antacid and 40 mg of simethicone per teaspoon.
Mylanta also offers a product called Mylanta Ultimate Strength, which bumps up to 500 mg of each antacid per teaspoon and drops the simethicone entirely. Maalox does not have an equivalent to this particular formulation.
How These Antacids Work
The aluminum hydroxide in both products breaks apart in your stomach and releases molecules that bind to acid, converting it into water and harmless salts. This raises the pH of your stomach contents, making them less acidic and easing heartburn, indigestion, and sour stomach. Magnesium hydroxide does the same thing through a similar chemical reaction.
The reason both ingredients are combined in one product is practical: aluminum hydroxide tends to cause constipation, while magnesium hydroxide tends to cause loose stools. Pairing them together helps the two effects cancel each other out, so most people experience neither problem. The simethicone component works differently. It breaks up gas bubbles in your digestive tract, relieving bloating and pressure. It doesn’t affect stomach acid at all.
One Key Difference: Availability
Brand-name Maalox liquid has been discontinued in the United States. You can still find generic versions with the same formula on pharmacy shelves, but the Maalox-branded bottle is no longer manufactured. Mylanta remains available as a brand-name product. If you’ve been using Maalox and can no longer find it, switching to Mylanta (or any store-brand equivalent with matching ingredients and concentrations) gives you the exact same medication.
Side Effects to Watch For
Because Mylanta and Maalox share the same formula, they carry the same side effect profile. The most common issues are constipation from the aluminum component and diarrhea from the magnesium component. For most people taking normal doses, these balance out and cause no trouble.
Longer-term or heavy use can cause more significant problems. Aluminum hydroxide binds to phosphate in your digestive tract, which can lower your body’s phosphate levels over time. Low phosphate affects bone health and energy levels. The magnesium component poses a particular risk for people with kidney disease, because compromised kidneys cannot efficiently clear excess magnesium from the blood. This can lead to dangerously high magnesium levels, especially in older adults.
Dosage Limits
For the maximum strength liquid, the standard limit is no more than 60 ml (about 4 tablespoons) in a 24-hour period. You should not use either product at its maximum dose for more than two weeks straight without medical guidance. This two-week ceiling exists because of the mineral imbalances that can develop with prolonged use, particularly the phosphate depletion caused by aluminum hydroxide.
If your heartburn or indigestion regularly lasts beyond two weeks, the underlying cause likely needs a different approach than a neutralizing antacid. Persistent acid reflux, for example, is typically managed with medications that reduce acid production rather than neutralize it after the fact.
Choosing Between Them
There is no clinical reason to prefer one over the other. If both were sitting on the shelf at the same price, you could pick either one and get identical relief. In practice, the decision comes down to what your pharmacy stocks and what costs less. Since brand-name Maalox is no longer sold in the U.S., you’re most likely choosing between brand-name Mylanta and a generic aluminum hydroxide/magnesium hydroxide/simethicone product. Check the “Drug Facts” label on any generic to confirm the milligram amounts match the strength you want, and you’ll have the same product regardless of what name is on the box.