Pepsi Max uses Aspartame (E951) and Acesulfame K (E950) in place of sugar. A single can (330ml) contains 3 kcal and 0.3g of sugar.
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Pepsi Max contains 1 kcal, 0.1g of carbohydrate (0.1g sugar), 14mg of caffeine and 0.01g of salt per 100ml.
Pepsi Max contains 14mg of caffeine per 100ml, the highest of any standard cola on UK supermarket shelves, higher than Diet Coke (12mg) or Coca-Cola Zero Sugar (10mg). A 500ml bottle delivers 70mg of caffeine, equivalent to roughly one small espresso. It is the UK's second-best-selling individual soft drink brand by value after Coca-Cola Original.
Pepsi Max contains 0.1g of sugar per 100ml, placing it in the below the Sugar Tax threshold under the Soft Drinks Industry Levy. A single can (330ml) delivers 0.3g of sugar, 1% of the adult daily free sugar limit.
Pepsi Max uses Aspartame (E951) and Acesulfame K (E950) 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.
Aspartame breaks down in the body into phenylalanine, aspartic acid and methanol. For most people, these metabolites are processed normally. However, people with phenylketonuria (PKU) cannot metabolise phenylalanine safely, which is why any product containing aspartame is legally required to carry the warning 'Contains a source of phenylalanine' on the label. In July 2023, IARC (the WHO's cancer research agency) classified aspartame as 'possibly carcinogenic to humans' (Group 2B) — the same classification as aloe vera extract and coffee — while simultaneously the Joint WHO/FAO Expert Committee on Food Additives confirmed the existing Acceptable Daily Intake (40mg per kilogram of body weight per day) remains safe. The two bodies are not contradicting each other: Group 2B means there is limited evidence of possible risk, not that consumption at normal levels is dangerous.
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.
People with phenylketonuria (PKU) must avoid Pepsi Max due to its aspartame content.
Pepsi Max contains 14mg of caffeine per 100ml. A single can (330ml) delivers 46mg of caffeine, 12% of the adult daily limit. For context, a standard 240ml filtered coffee contains approximately 95 to 120mg of caffeine.
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.