Is Gaviscon Better Than Tums for Heartburn?

Gaviscon generally outperforms Tums for heartburn relief, and the reason comes down to how the two products work. Tums neutralizes stomach acid directly with calcium carbonate, while Gaviscon adds an alginate-based barrier that physically blocks acid from reaching the esophagus. Clinical studies have found Gaviscon equal to or better than traditional antacids like Tums for relieving heartburn symptoms, with the advantage growing wider the longer you track relief after a dose. The difference is real, but it is not always dramatic, and which product suits you better depends on your symptoms, how often you reach for relief, and which formulation of Gaviscon you can actually buy where you live.

Two Different Approaches to the Same Problem

Tums is a straightforward antacid. It contains calcium carbonate, which reacts with hydrochloric acid in your stomach and raises the pH. The effect is fast, often noticeable within minutes, and wears off relatively quickly as your stomach continues producing acid. Gaviscon contains antacid ingredients too, but its defining feature is sodium alginate, a compound derived from seaweed. When alginate hits stomach acid, it forms a gel-like “raft” that floats on top of whatever is in your stomach.

That raft serves as a physical lid. Instead of just chemically neutralizing acid, it sits at the junction between the stomach and esophagus, making it harder for acidic contents to splash upward during reflux events. The raft forms within seconds of dosing, so the onset of relief is comparable to a standard antacid. But because the raft can persist in the stomach for several hours, the relief tends to last longer than what a plain antacid delivers.

What the Clinical Evidence Shows

A review of alginate-raft formulations found that Gaviscon is superior to placebo and equal to or significantly better than traditional antacids for heartburn symptom relief, with the raft’s persistence in the stomach being a key advantage over products that only neutralize acid temporarily.¹ The strongest head-to-head data comes from a crossover trial comparing Liquid Gaviscon to a magnesium-aluminum antacid gel. In that study, about 84% of patients reported good symptom relief with Gaviscon, compared to just 23% during antacid therapy. Relief came within 15 minutes for roughly two-thirds of Gaviscon users versus fewer than one in ten antacid users, and the benefit lasted more than four hours in three-quarters of the Gaviscon group compared to about a quarter of the antacid group.²

A more recent double-blind crossover study using pH monitoring confirmed the mechanism behind these symptom differences. Patients taking Gaviscon Double Action had significantly less acid exposure in the lower esophagus during the 30 to 150 minutes after eating, compared to an antacid alone. The number of reflux events was similar between the two treatments, meaning Gaviscon did not stop reflux episodes from happening. What it did was make the material that refluxed less acidic, because the raft was sitting on top of the stomach contents and neutralizing what splashed upward.³

The Post-Meal Acid Pocket

One of the more interesting findings about Gaviscon involves something called the acid pocket. After you eat, a layer of unbuffered acid tends to form on top of the food in your stomach, sitting right near the junction where the esophagus meets the stomach. This pocket of concentrated acid is a major driver of post-meal heartburn, and ordinary antacids do not always reach it effectively because they mix into the meal below.

Research using pH sensors placed inside patients showed that an alginate-antacid formulation could either neutralize or physically displace this acid pocket away from the esophageal junction. The alginate raft floated right to the top of gastric contents, parking itself exactly where the acid pocket would otherwise sit.⁴ This is Gaviscon’s most distinctive advantage over Tums: it addresses the specific anatomy of post-meal reflux rather than just raising the average pH of stomach contents.

Late-Night Eating and Nighttime Reflux

Heartburn after a late meal is one of the most common complaints, especially among people who carry extra weight. A randomized trial in obese individuals compared Gaviscon Advance to a non-alginate antacid after a late-night supper. Gaviscon Advance suppressed the acid pocket’s pH more effectively than the antacid and significantly reduced the percentage of time the esophagus was exposed to acid below pH 4. Symptom frequency and severity scores also dropped more with the alginate formulation.⁵

If your heartburn is mainly triggered by lying down after eating, this is where Gaviscon’s raft mechanism matters most. When you are upright, gravity helps keep stomach acid down. When you recline, a floating alginate barrier can make a bigger practical difference than dissolved antacid that has already mixed into your stomach contents.

Which Gaviscon Are You Actually Buying?

This is where things get confusing, and it is the single biggest caveat in any Gaviscon-versus-Tums comparison. Gaviscon is not the same product everywhere. A study comparing four international formulations of Liquid Gaviscon found that each had markedly different raft strength and acid-neutralization profiles. Formulations that include more antacid materials tend to neutralize more acid but form weaker rafts, reducing the barrier’s ability to plug the opening of the esophagus. Formulations with more alginate and less antacid form stronger rafts but neutralize less acid directly.¹

In the United States, Gaviscon products tend to contain aluminum hydroxide and magnesium carbonate alongside alginate, leaning more toward the antacid side. In the UK, Gaviscon Advance contains a higher concentration of sodium alginate and potassium bicarbonate, producing a stronger raft. Many of the clinical trials showing Gaviscon’s superiority over plain antacids were conducted with UK formulations. If you are buying Gaviscon in the US, the product may still outperform Tums, but the gap could be smaller than the published studies suggest. Some people in the US order Gaviscon Advance from international retailers for this reason.

Safety Trade-Offs

Both products are generally safe for occasional use, but they have different risk profiles worth understanding if you take them regularly.

Tums’ main ingredient, calcium carbonate, can cause problems when consumed in large amounts over time. The most serious is hypercalcemia, where calcium levels in the blood rise high enough to cause nausea, confusion, kidney damage, and in extreme cases a medical emergency.⁶ Case reports document this happening from long-term excessive self-medication with calcium-rich antacid tablets, sometimes leading to acute pancreatitis.⁷ These are extreme cases, usually involving people who take far more than the recommended dose for months or years. But they illustrate a real ceiling on how freely you should consume calcium carbonate antacids.

Gaviscon’s concern runs in a different direction: sodium. Several Gaviscon formulations contain meaningful amounts of sodium, which matters for people managing high blood pressure or heart disease. A systematic review found that patients prescribed high-sodium-containing drugs had a higher risk of cardiovascular events, including stroke and all-cause mortality, compared to those on alternatives.⁸ This does not mean a single dose of Gaviscon is dangerous, but if you are taking it multiple times a day for weeks on end and you already have hypertension, the cumulative sodium load is worth discussing with your doctor. Some low-sodium Gaviscon formulations exist, but availability varies by market.

Heartburn During Pregnancy

Heartburn affects the majority of pregnant women, especially in the third trimester, and medication choices become more cautious. A scoping review of alginate therapy for reflux during pregnancy found that alginates and antacids produced similar improvements in heartburn intensity and frequency. Few maternal side effects were reported with alginates, and no fetal or neonatal outcomes were linked to treatment. The safety profile of alginates was comparable to both PPIs and antacids.⁹

A dedicated prospective study of Liquid Gaviscon in pregnant women found that treatment was successful in about 91% of patients as judged by clinicians and 90% as judged by the women themselves. Serum sodium levels remained unchanged, and the few adverse events reported were consistent with what you would see in the general pregnant population anyway.¹⁰ Both Tums and Gaviscon are considered reasonable choices during pregnancy. Tums has the extra appeal of providing supplemental calcium, which many pregnant women need. Gaviscon may offer longer-lasting relief, which matters when you are trying to sleep in the third trimester.

Using Gaviscon Alongside a PPI

Many people with chronic reflux already take a proton pump inhibitor like omeprazole but still get breakthrough symptoms, particularly after meals or at night. There has been real interest in whether adding Gaviscon on top of a PPI can fill that gap.

A randomized trial of Gaviscon Advance as add-on therapy in PPI patients who still had symptoms found that reflux scores improved significantly more with Gaviscon than with placebo, and nights with symptoms dropped more in the Gaviscon group.¹¹ A separate two-phase trial of Gaviscon Double Action as a PPI add-on told a more mixed story: the exploratory phase found a significant benefit, but the confirmatory phase showed improvement with Gaviscon that was not significantly different from placebo, with response rates of 51% versus 48%.¹²

The takeaway is that Gaviscon can help with PPI breakthrough symptoms, but the placebo response in reflux trials tends to be high, which makes it hard to show a clean statistical win. For occasional post-meal flare-ups despite a PPI, it is a reasonable option. A plain antacid like Tums can also help with PPI breakthrough, but the duration of relief will be shorter, which matters more at bedtime.

Beyond Acid: Pepsin and Bile

Heartburn is not just about acid. Pepsin, a digestive enzyme, and bile acids from the small intestine can also reflux into the esophagus and cause tissue irritation. This is especially relevant in a condition called laryngopharyngeal reflux, where refluxed material reaches the throat and voice box, causing hoarseness, throat clearing, and a persistent cough rather than classic burning chest pain.

Laboratory research found that Gaviscon Advance’s alginate raft could retard the diffusion of both pepsin and multiple bile acids, and when tested in a simulated reflux model, the raft removed pepsin and bile acids from the refluxed material. The raft had enough capacity to trap these irritants across multiple reflux events, not just one.¹³ A clinical study in patients with laryngopharyngeal reflux found that Gaviscon Advance produced significant improvements in both symptom scores and clinical findings compared to controls at two and six months.¹⁴

This is a dimension where Tums simply cannot compete. Calcium carbonate neutralizes acid, but it does nothing to physically trap pepsin or bile. If your symptoms include throat irritation, chronic cough, or a feeling of something stuck in your throat rather than straightforward heartburn, an alginate product has a meaningful mechanistic advantage.

Iron Absorption and Other Nutrient Concerns

One practical wrinkle with antacids that rarely gets mentioned: they can interfere with iron absorption. A study measuring plasma iron levels after simultaneous ingestion found that calcium carbonate reduced the plasma iron increase by about two-thirds compared to controls, and sodium bicarbonate reduced it by about half.¹⁵ If you take iron supplements or are managing iron deficiency, timing matters. Taking Tums at the same time as your iron pill could undercut the supplement’s effectiveness. Gaviscon formulations that contain aluminum or magnesium antacids can have similar interactions, though the alginate component itself is not implicated. The simplest fix is to separate antacid and iron doses by at least two hours.

When Tums Might Actually Be the Better Pick

Despite Gaviscon’s advantages in most head-to-head comparisons, there are scenarios where Tums makes more practical sense. If you get heartburn once or twice a month and just want a few quick-dissolving tablets you can carry in a pocket, Tums is hard to beat for convenience. Liquid Gaviscon works best but is bulky to carry around. Chewable Gaviscon tablets exist but do not form as robust a raft as the liquid.

Cost also plays a role. Tums is cheap and widely available in nearly identical generic forms. Gaviscon’s price varies, and the stronger UK-style formulations cost more to import. For someone managing occasional, mild heartburn after a rich meal, the clinical difference between the two products is unlikely to matter in any practical way.

Tums also has the minor benefit of providing supplemental calcium, which can be useful for people at risk of osteoporosis, though it should never be your primary calcium source given the hypercalcemia risk of overconsumption. And for people on sodium-restricted diets who have been told to keep sodium intake very low, a calcium carbonate antacid sidesteps the sodium concern that some Gaviscon formulations carry.

When to Stop Self-Treating Entirely

Whether you choose Gaviscon, Tums, or anything else over the counter, frequent heartburn that persists for more than two weeks deserves a conversation with a doctor. Chronic reflux can damage the esophageal lining over time, and the symptom overlap between heartburn and more serious conditions is wide enough that long-term self-treatment without evaluation carries real risk. Neither Gaviscon nor Tums treats the underlying cause of reflux; they manage symptoms while the reflux continues. If you find yourself reaching for either product daily, that is a signal to investigate rather than just reach for a bigger bottle.