Understanding Gaviscon's Core Mechanism: The Alginate Raft
Before diving into the differences, it's essential to understand what makes most Gaviscon products (particularly those in the UK and Australia) unique. The key active ingredient is sodium alginate, a natural substance derived from seaweed [1.3.4]. When sodium alginate comes into contact with stomach acid, it reacts to form a thick, gel-like layer, often referred to as a 'raft' [1.5.2].
This raft floats on top of the stomach contents and acts as a physical barrier, preventing stomach acid, pepsin, and bile from refluxing back up into the esophagus [1.5.1, 1.5.2]. This mechanism provides rapid relief that can last significantly longer than traditional antacids—up to four hours [1.5.3, 1.3.4]. The raft effectively suppresses reflux by physically blocking it and can even displace the 'acid pocket'—an unbuffered layer of acid that sits atop a meal—away from the esophagus [1.5.6].
A Critical Distinction: UK vs. US Gaviscon
A major point of confusion for consumers is the significant difference in formulation between Gaviscon sold in the United Kingdom (and other international markets) and that sold in the United States. They are made by different companies and are not the same product [1.4.1].
- UK Gaviscon: These formulations, such as Gaviscon Advance, prioritize sodium alginate as the primary active ingredient to create the protective raft [1.3.3]. This is the version renowned for its barrier-forming action.
- US Gaviscon: The US version typically contains aluminum hydroxide and magnesium carbonate, which are simple antacids that work by neutralizing stomach acid [1.3.7]. While some US products contain alginic acid, it is often in much lower amounts and listed as an inactive ingredient, meaning it does not provide the same effective raft-forming benefit as its UK counterpart [1.4.1].
For the purpose of comparing the main types, this article will focus on the UK formulations, which are centered around alginate therapy.
Gaviscon Advance: Extra Strength Barrier
Gaviscon Advance is designed for more persistent or severe symptoms of heartburn and acid reflux [1.2.5]. Its key feature is its strength.
Key Ingredients and Action:
- Double Strength Sodium Alginate: Gaviscon Advance contains twice the concentration of sodium alginate (1000mg per 10ml) compared to Gaviscon Original [1.2.2, 1.2.6]. This creates a stronger, more resilient raft for maximum barrier protection [1.2.4].
- Potassium Bicarbonate: Works with the alginate to help form the raft.
- Low Sodium: It has the lowest sodium content in the Gaviscon range, making it a more suitable option for individuals on a sodium-restricted diet, as well as during pregnancy and breastfeeding [1.2.4, 1.3.3].
It works purely by forming this robust physical barrier, without a primary antacid component for neutralizing acid in the stomach itself [1.2.5]. This makes it ideal for managing the physical backflow of reflux.
Gaviscon Double Action: Two-Fold Relief
Gaviscon Double Action is the best-selling product in the family, offering a comprehensive approach to relief [1.3.5]. It tackles both heartburn and indigestion simultaneously.
Key Ingredients and Action:
- Sodium Alginate & Bicarbonates: It contains sodium alginate to form the protective raft over the stomach contents [1.3.5].
- Antacid Power (Calcium Carbonate): In addition to the raft, it contains a higher level of calcium carbonate, an antacid that works to neutralize excess stomach acid [1.2.2, 1.3.5].
This dual mechanism means it not only prevents reflux but also soothes the discomfort of indigestion caused by excess acid, providing both fast and long-lasting relief [1.3.8].
Gaviscon Original: The Classic Formula
Gaviscon Original is the classic formulation that provides fast, soothing relief from standard heartburn and indigestion [1.2.5].
Key Ingredients and Action:
- Sodium Alginate, Sodium Bicarbonate, Calcium Carbonate: Like Double Action, it combines the raft-forming alginate with acid-neutralizing antacids [1.2.2]. However, the concentrations of these ingredients are different. It has less sodium alginate than Gaviscon Advance and less calcium carbonate than Gaviscon Double Action [1.2.2].
It provides reliable, effective relief and is a suitable starting point for those experiencing occasional symptoms.
Comparison Table
| Feature | Gaviscon Advance | Gaviscon Double Action | Gaviscon Original |
|---|---|---|---|
| Primary Function | Extra-strength physical barrier [1.2.4] | Physical barrier + Acid neutralization [1.3.5] | Physical barrier + Acid neutralization [1.2.5] |
| Sodium Alginate | 1000mg per 10ml (Double strength) [1.2.2] | 500mg per 10ml | 500mg per 10ml |
| Antacids | No primary antacid component | High level of Calcium Carbonate [1.2.2] | Standard level of Calcium Carbonate |
| Best For | Severe, persistent reflux (GERD) [1.2.5] | Heartburn and indigestion [1.3.8] | Occasional heartburn and indigestion [1.2.5] |
| Sodium Content | Lowest in the range [1.2.4] | Standard | Standard |
| Forms Available | Liquid, Tablets [1.2.4] | Liquid, Tablets, Sachets [1.2.3] | Liquid, Tablets [1.2.3] |
Conclusion: Which Gaviscon is Right for You?
Choosing the right Gaviscon depends on your specific symptoms. For severe and frequent reflux where the primary issue is stomach contents moving into the esophagus, Gaviscon Advance offers the strongest protective barrier. For those who suffer from both the burning of heartburn and the discomfort of indigestion, Gaviscon Double Action provides a two-pronged solution by both forming a barrier and neutralizing acid. Gaviscon Original remains a solid and effective choice for reliable relief from occasional symptoms.
As with any medication, it is important to read the label and consult with a pharmacist or doctor to ensure you are selecting the most appropriate treatment for your needs, especially if you have underlying health conditions, are pregnant, or are taking other medications.
Authoritative Link: Learn more about alginates for GERD from the Cleveland Clinic [1.5.5]
