Gaviscon Advance and Gaviscon Extra Strength work in different ways. Gaviscon Advance (the UK formula) is an alginate: 1,000 mg of sodium alginate per 10 ml forms a thick raft that floats on your stomach contents and physically blocks reflux. Gaviscon Extra Strength (the US formula) is an antacid: its active ingredients are aluminum hydroxide and magnesium carbonate, which neutralize acid, with only a small, unlisted amount of alginate as an inactive ingredient.

For occasional heartburn, both will help. For silent reflux (LPR), regurgitation or night-time reflux, Gaviscon Advance is the better choice. It blocks reflux rather than just neutralizing it, can trap pepsin, contains no aluminum, and has clinical trial evidence in LPR.

The liquid works faster and coats better than the tablets for both products, so it’s usually the better choice for throat symptoms and bedtime.

Key Takeaways

Gaviscon Advance: sodium alginate 1,000 mg and potassium bicarbonate 200 mg per 10 ml. No aluminum or magnesium.
Gaviscon Extra Strength liquid: aluminum hydroxide 254 mg and magnesium carbonate 237.5 mg per 5 ml, with sodium alginate as an inactive ingredient.
Advance blocks reflux with a raft. Extra Strength mainly neutralizes acid.
Advance has randomized trial evidence for silent reflux. Extra Strength doesn’t.
Regular UK Gaviscon contains half the alginate of Advance, plus more sodium and calcium carbonate.
Extra Strength can cause constipation (aluminum) or diarrhea (magnesium) and needs caution in kidney disease.
Advance is high in sodium and contains potassium, so it also needs caution in kidney or heart disease.
Liquid generally beats tablets for throat symptoms and night-time reflux.

Gaviscon Advance vs Extra Strength at a Glance

Where it’s sold: Advance in the UK, Europe and elsewhere (made by Reckitt). Extra Strength in the US (distributed by Haleon).
Type: Advance is an alginate raft-former. Extra Strength is an aluminum-magnesium antacid.
Active ingredients: Advance: sodium alginate and potassium bicarbonate. Extra Strength: aluminum hydroxide and magnesium carbonate.
Alginate content: Advance: 1,000 mg per 10 ml. Extra Strength: not stated, inactive ingredient only.
Aluminum: Advance: none. Extra Strength: yes.
Blocks reflux: Advance: yes, strong raft. Extra Strength: weak at best.
Traps pepsin and bile: Advance: yes, in lab testing. Extra Strength: not shown.
LPR trial evidence: Advance: yes. Extra Strength: none.
Best for: Advance: LPR, regurgitation, night-time reflux, reflux that PPIs haven’t fixed. Extra Strength: occasional heartburn and indigestion.

What’s Actually in Each One

Gaviscon Advance (UK)

Gaviscon Advance liquid contains sodium alginate 1,000 mg and potassium hydrogen carbonate (potassium bicarbonate) 200 mg per 10 ml [Gaviscon Advance Aniseed Oral Suspension, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)]. The chewable tablets contain sodium alginate 500 mg and potassium bicarbonate 100 mg each [Gaviscon Advance Mint Chewable Tablets, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)].

The alginate is the active part. The potassium bicarbonate reacts with stomach acid to release carbon dioxide, which gets trapped in the alginate gel and makes it float.

Gaviscon Extra Strength (US)

Gaviscon Extra Strength liquid contains aluminum hydroxide 254 mg and magnesium carbonate 237.5 mg per 5 ml, with sodium alginate listed among the inactive ingredients [Gaviscon Liquid, Drug Facts label, Haleon]. The Extra Strength chewable tablets contain aluminum hydroxide 160 mg and magnesium carbonate 105 mg per tablet, with alginic acid and sodium bicarbonate among the inactive ingredients [Gaviscon Extra Strength Chewable Tablets, Drug Facts label, Haleon].

Aluminum hydroxide and magnesium carbonate are classic antacids. They react directly with stomach acid and neutralize it. Because the alginate isn’t counted as an active ingredient, the label doesn’t say how much is in there. I explain why the US product is formulated this way in Gaviscon Advance in the US.

How They Work Differently

Neutralizing vs blocking

An antacid reduces how acidic your stomach contents are. It doesn’t stop them coming up. If you reflux after taking Extra Strength, the material that reaches your esophagus or throat is less acidic, but it’s still there, and it still contains pepsin.

An alginate raft works on whether reflux happens at all. It floats on top of your stomach contents at the junction with the esophagus, where reflux starts. Imaging studies show the raft sitting on the “acid pocket” at the top of the stomach. In one study, an alginate-antacid pushed this acid pocket below the diaphragm in 71% of patients compared with 21% on an antacid alone, and reduced acid reflux episodes [Rohof et al., Clinical Gastroenterology and Hepatology, 2013].

Why that matters for silent reflux

In LPR, the damage in the throat comes mainly from pepsin, not just acid. Pepsin can stick to throat tissue and be reactivated later by acid from reflux or from food and drink. Neutralizing stomach acid doesn’t solve that. Reducing how much reflux reaches the throat does. The official product information for Gaviscon Advance notes that, in lab testing, the raft can trap pepsin and bile within its structure [Gaviscon Advance Peppermint Oral Suspension, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)]. See how pepsin reactivates in the throat.

Raft strength

Not all rafts are equal. In a lab comparison of alginate products, Gaviscon Advance had the highest alginate content in its raft and kept neutralizing for about 93 minutes, compared with 5 to 27 minutes for weaker products [Dettmar et al., Drug Development and Industrial Pharmacy, 2018]. A product where alginate is only an inactive ingredient is unlikely to come close.

The Evidence

Alginates as a class have strong evidence. A meta-analysis of 14 randomized trials found that alginate therapy more than quadrupled the odds of resolving GERD symptoms compared with placebo or antacids [Leiman et al., Diseases of the Esophagus, 2017]. Notice the comparison: alginates beat antacids.

For throat symptoms specifically, a randomized trial in 49 people with LPR found those taking Gaviscon Advance had significantly better symptom and throat examination scores than untreated controls [McGlashan et al., European Archives of Oto-Rhino-Laryngology, 2009]. There’s no equivalent evidence for US Gaviscon Extra Strength in LPR.

Side Effects and Safety

Gaviscon Extra Strength

Constipation from aluminum, or diarrhea from magnesium. The label notes a possible laxative effect.
Kidney disease: aluminum and magnesium can build up if your kidneys don’t clear them well. Ask your doctor first.
Drug interactions: antacids reduce absorption of some medicines, including certain antibiotics, thyroid tablets and iron.
Duration: the label advises not using the maximum dose for more than 2 weeks without a doctor’s advice.

Gaviscon Advance

Sodium: about 58 mg per 5 ml, so it’s considered high in sodium. Take care if you’re on a low-salt diet or have heart failure.
Potassium: about 1 mmol per 5 ml. Take care if you have kidney disease or are on a potassium-restricted diet.
Drug interactions: leave about 2 hours between Gaviscon Advance and other medicines, especially thyroid tablets, iron, some antibiotics and bisphosphonates.
No aluminum, so no constipation from that source, which is one reason many people prefer it for long-term use.

Gaviscon vs Gaviscon Advance (UK)

If you’re in the UK, the more relevant comparison is often regular Gaviscon against Gaviscon Advance. Regular Gaviscon liquid contains sodium alginate 500 mg, sodium bicarbonate 267 mg and calcium carbonate 160 mg per 10 ml, with about 143 mg of sodium per 10 ml [Gaviscon Liquid Sachets Mint Flavour, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)].

Alginate: Advance has double (1,000 mg vs 500 mg per 10 ml).
Sodium: Advance has less (about 116 mg vs 143 mg per 10 ml).
Antacid: regular Gaviscon adds calcium carbonate for extra neutralizing. Advance doesn’t.
LPR evidence: Advance is the version used in the LPR trials.

Gaviscon Double Action adds more calcium carbonate for a stronger antacid effect alongside the raft. For heartburn, regular or Double Action are fine. For silent reflux, Advance is the one to choose.

Tablets vs Liquid

Both Gaviscon Advance and Extra Strength come as liquid and chewable tablets. In my experience, and in what I hear from readers, the liquid is better for most reflux problems:

Liquid forms a raft quickly and evenly, and it coats on the way down. It’s the better choice for the bedtime dose and for throat symptoms.
Tablets have to be chewed thoroughly to work, and the raft can be less complete. They’re far more convenient for travel, work and eating out.

Ten ml of Advance liquid gives you 1,000 mg of alginate. Two Advance tablets give the same. If you use tablets, chew them well and follow with a small sip of water rather than a large drink, which can break the raft up.

I use the liquid at home and keep tablets in a bag or car for when I’m out.

Which Should You Choose?

Choose Gaviscon Extra Strength if:

You get occasional heartburn after a big meal
You’re in the US and want something from the pharmacy now
You don’t have throat symptoms

Choose Gaviscon Advance if:

You have silent reflux: throat clearing, hoarseness, a lump in your throat or post-nasal drip
You get regurgitation or night-time reflux
PPIs haven’t fixed your symptoms
You want to avoid aluminum for regular use

If you’re in the US and want an alginate without importing, Reflux Gourmet is the closest option. See Reflux Gourmet vs Gaviscon. For more on the whole category, see alginates for acid reflux, and for a plain antacid comparison, Tums vs Gaviscon.

Whichever you use, it’s a tool, not a cure. An alginate blocks reflux for a few hours, but what you eat decides how much reflux there is to block. That’s what the Wipeout Diet Plan is built to fix.

Conclusion

Gaviscon Advance and Gaviscon Extra Strength share a brand but not a mechanism. Extra Strength is an aluminum and magnesium antacid that neutralizes acid. Advance is a high-dose alginate that forms a raft, blocks reflux, traps pepsin in lab testing and has trial evidence in silent reflux. For occasional heartburn, either works. For LPR, regurgitation or night-time reflux, Advance is clearly the better product, ideally as the liquid, taken after meals and at bedtime. My full guide is in Gaviscon Advance for LPR.

To get the most out of an alginate, pair it with the right diet. The Wipeout Diet Plan is my complete plan for cutting reflux at the source, and it’s what I recommend alongside Gaviscon Advance in my consults. It was built first for silent reflux, but because it targets the same underlying mechanisms, it works just as well for GERD and classic heartburn.

If you’d rather start with something lighter, the Wipeout Food Reference Guide is the essential companion. It lists the foods and drinks that are safe for acid reflux and LPR, along with their pH values.

Frequently Asked Questions

What’s the difference between Gaviscon Advance and Extra Strength?

Gaviscon Advance is an alginate with 1,000 mg sodium alginate per 10 ml that forms a raft to block reflux. Gaviscon Extra Strength is a US antacid with aluminum hydroxide and magnesium carbonate as its active ingredients and only a small amount of alginate as an inactive ingredient.

Is Gaviscon Advance stronger than Extra Strength?

They’re strong in different ways. Extra Strength is a stronger acid neutralizer. Advance forms a much stronger raft that blocks reflux. For silent reflux and night-time reflux, the raft matters more.

What’s the difference between Gaviscon and Gaviscon Advance?

In the UK, regular Gaviscon contains 500 mg sodium alginate per 10 ml plus sodium bicarbonate and calcium carbonate. Gaviscon Advance contains 1,000 mg sodium alginate with potassium bicarbonate and less sodium. In the US, regular Gaviscon is an aluminum-magnesium antacid.

Which Gaviscon is best for silent reflux?

Gaviscon Advance. It forms the strongest raft, can trap pepsin in lab testing, contains no aluminum and is the version tested in LPR trials. The liquid taken at bedtime is the most useful dose.

Are Gaviscon tablets or liquid better?

The liquid usually works better for throat symptoms and night-time reflux, because it forms a raft quickly and coats as it goes down. Tablets are more convenient for travel and need to be chewed thoroughly.

Can I take Gaviscon Extra Strength every day?

The label advises not taking the maximum dose for more than 2 weeks without a doctor’s advice. If you need an antacid every day, see your doctor to find out what’s driving your reflux.

Does Gaviscon Extra Strength contain alginate?

Yes, but only as an inactive ingredient. The liquid contains sodium alginate and the tablets contain alginic acid, in amounts that aren’t stated on the label. Its active ingredients are aluminum hydroxide and magnesium carbonate.

Research & References

[Gaviscon Advance Aniseed Oral Suspension, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)] — Lists sodium alginate 1,000 mg and potassium hydrogen carbonate 200 mg per 10 ml, adult dosing and sodium content.
[Gaviscon Advance Mint Chewable Tablets, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)] — Lists sodium alginate 500 mg and potassium bicarbonate 100 mg per tablet, with 53 mg sodium per tablet.
[Gaviscon Advance Peppermint Oral Suspension, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)] — Describes the raft blocking reflux for up to about 4 hours and trapping bile and pepsin in vitro, with cautions on sodium, potassium and drug interactions.
[Gaviscon Liquid Sachets Mint Flavour, Summary of Product Characteristics, Reckitt Benckiser Healthcare (UK)] — Regular Gaviscon formula: sodium alginate 500 mg, sodium bicarbonate 267 mg and calcium carbonate 160 mg per 10 ml, with 142.6 mg sodium.
[Gaviscon Liquid, Drug Facts label, Haleon] — US Extra Strength liquid: aluminum hydroxide 254 mg and magnesium carbonate 237.5 mg per 5 ml, with sodium alginate listed as an inactive ingredient.
[Gaviscon Extra Strength Chewable Tablets, Drug Facts label, Haleon] — US Extra Strength tablets: aluminum hydroxide 160 mg and magnesium carbonate 105 mg per tablet, with alginic acid and sodium bicarbonate as inactive ingredients.
[Rohof et al., Clinical Gastroenterology and Hepatology, 2013] — An alginate-antacid raft displaced the postprandial acid pocket below the diaphragm in 71% of GERD patients versus 21% on antacid alone, and reduced acid reflux episodes.
[Dettmar et al., Drug Development and Industrial Pharmacy, 2018] — Lab comparison of alginate products; Gaviscon Advance had the highest raft alginate content and maintained neutralization for about 93 minutes, versus 5 to 27 minutes for weaker products.
[Leiman et al., Diseases of the Esophagus, 2017] — Meta-analysis of 14 randomized trials finding alginates increased the odds of GERD symptom resolution more than fourfold versus placebo or antacids.
[McGlashan et al., European Archives of Oto-Rhino-Laryngology, 2009] — Randomized trial of Gaviscon Advance in 49 patients with LPR; the treated group had significantly better symptom and examination scores than untreated controls.

David Gray

12 years living with LPR · Consultant & researcher

Every claim sourced to peer-reviewed research Editorial policy

I've lived with LPR for twelve years — the misdiagnoses, the PPI courses that did nothing, the slow work of figuring out what actually helps. Wipeout Reflux is where I translate the research into plain terms for people stuck in the same place. Every claim here is sourced to peer-reviewed work, and I consult one-to-one with LPR sufferers.

View all articles by David Gray

Gaviscon Advance vs Extra Strength: Key Differences