Monster Energy Ultra Zero Sugar uses Sucralose (E955) and Erythritol (E968) in place of sugar. A can/bottle (500ml) contains 25 kcal and 1.5g of sugar.
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Monster Energy Ultra Zero Sugar contains 5 kcal, 0.4g of carbohydrate (0.3g sugar), 32mg of caffeine and 0.18g of salt per 100ml.
Monster Ultra Zero Sugar has the same 160mg of caffeine per 500ml can as regular Monster Energy. Erythritol (a sugar alcohol that provides negligible calories) and sucralose replace the sucrose and glucose of the original. Zero sugar Monster variants were the fastest-growing segment in the UK energy drink category in 2024.
Monster Energy Ultra Zero Sugar contains 0.3g of sugar per 100ml, placing it in the below the Sugar Tax threshold under the Soft Drinks Industry Levy. A can/bottle (500ml) delivers 1.5g of sugar, 5% of the adult daily free sugar limit.
Monster Energy Ultra Zero Sugar uses Sucralose (E955) and Erythritol (E968) in place of all of the sugar, with multiple sweeteners blended to better replicate the taste of sugar than any single sweetener can alone. Sweeteners deliver a sweet taste without the calories of sugar, but they are not nutritionally neutral — the evidence on their effects is more nuanced than most drinks marketing acknowledges.
In 2023 the World Health Organization issued a formal advisory recommending against using non-sugar sweeteners for weight control, stating that the long-term evidence does not show they help people manage weight or reduce the risk of obesity-related conditions. The WHO classified its guidance as a conditional recommendation, reflecting that the evidence is still emerging, but the direction is clear: sweeteners are not a straightforward healthy alternative to sugar.
A growing body of research suggests artificial sweeteners may disrupt the gut microbiome, the community of bacteria in the digestive tract that plays a role in metabolism, immunity and mood regulation. A 2022 study published in Cell found that sucralose, saccharin and stevia altered gut bacterial composition in healthy adults, with individual responses varying significantly. The long-term significance of these microbiome changes is not yet established, but the findings support treating sweeteners as active food compounds rather than inert additives.
Sweeteners may also affect appetite regulation. Because they stimulate sweet taste receptors without delivering the expected calories, some research suggests the brain's reward response to sweet taste becomes partially decoupled from energy intake over time. The evidence here is contested: some studies find sweetener users compensate by eating more elsewhere, while others find no effect. What is clear is that sweetened drinks, whether sugar-sweetened or sweetener-sweetened, are associated in epidemiological data with continued desire for sweet-tasting foods rather than reducing it.
Sucralose is derived from sugar through a chemical process that substitutes three hydroxyl groups with chlorine atoms. Unlike aspartame, it is heat-stable and passes through the body largely unchanged. Some in vitro research has raised questions about whether sucralose degrades into potentially harmful compounds at high temperatures, but the European Food Safety Authority reviewed these studies and concluded that sucralose at normal dietary exposure levels is safe. The 2022 Cell study specifically identified sucralose as one of the sweeteners that most significantly altered gut microbiome composition in human subjects.
Erythritol is a sugar alcohol that occurs naturally in some fruits and fermented foods. Unlike most sugar alcohols, it is absorbed in the small intestine rather than fermented by gut bacteria, meaning it causes less bloating than alternatives like sorbitol or maltitol. A 2023 study in Nature Medicine found elevated plasma erythritol levels associated with increased risk of major cardiovascular events. The study was observational (and erythritol is also produced naturally by the body), but it prompted significant scientific discussion about whether erythritol in food products should be more closely evaluated. No regulatory action has followed to date.
None of this means sweetener-containing drinks are dangerous at normal levels of consumption. Regulatory agencies in the UK, EU and worldwide continue to approve sweeteners at current dietary intake levels. The more useful question for daily nutrition decisions is whether drinks using sweeteners are genuinely better than the alternatives. The honest answer: a sweetener-containing drink is likely lower in calories and sugar than the full-sugar equivalent, but is probably not as neutral as drinking water, and should not be treated as a free pass to unlimited consumption.
Monster Energy Ultra Zero Sugar contains 32mg of caffeine per 100ml. A single can/bottle (500ml) delivers 160mg of caffeine, 40% of the adult daily limit (400mg). Drinks above 150mg of caffeine per litre must carry a 'high caffeine content' warning under UK law.
High-caffeine energy drinks are not recommended for children under 16, pregnant women or individuals sensitive to caffeine. The NHS advises pregnant women to limit total caffeine intake to 200mg per day from all sources.
Nutrition information from official brand UK nutrition panels, Coca-Cola GB nutrition pages, UK retailer product listings, and independent nutritionist analyses. Figures per 100ml; per-serving values are proportional estimates. Sugar Tax (SDIL) status based on UK sugar content thresholds at time of writing — brands may reformulate. Caffeine figures from EU/UK mandatory nutrition labelling. Reference intakes: EU Reference Intakes for an average adult (2,000 kcal). Fruit juice is subject to the SDIL if it contains added sugar; pure juices exempt. For guidance only, not medical advice.