Cyclamate

Cyclamate is a non-nutritive artificial sweetener (~30× sweeter than sugar) used to replace sugar in “diet” or sugar-free foods. In the 1960s it was a common sweetener for low-calorie soft drinks, but it was banned in the United States in 1969 after high-dose rodent studies suggested a link to bladder cancer. Today, cyclamate is still approved in over 100 countries (as additive E952) including Canada and the European Union, with acceptable daily intake limits to ensure safety. Typical human consumption stays well below these limits, and scientific reviews have found no clear cancer risk in people. However, because a small fraction of ingested cyclamate is converted into cyclohexylamine – a metabolite that caused reproductive organ harm in animal tests at high doses – health authorities treat cyclamate with caution.

Aliases / Common Names: Cyclamic acid (cyclohexanesulfamic acid); sodium cyclamate; calcium cyclamate; E952. Often marketed internationally under names like Sucaryl or as ingredients in tabletop sweeteners (e.g. certain formulations of Sweet’N Low or Sugar Twin). Regulatory Status & Exposure: In the U.S., cyclamate’s approval as a food additive was withdrawn in 1969 and it has not been reapproved since. The FDA’s ban means U.S. products cannot contain cyclamate. In contrast, over 100 countries (including those in the EU, Canada, and Asia) allow cyclamate in foods and beverages within regulated limits. The European Commission’s Scientific Committee on Food set a conservative acceptable daily intake (ADI) of 7 mg per kg body weight in 2000, while the Joint FAO/WHO Expert Committee on Food Additives (JECFA) established an ADI of 0–11 mg/kg bw. These ADIs incorporate safety factors to ensure lifetime use remains safe. Actual exposure for most consumers is far lower: a typical diet user consumes only on the order of a few mg/kg per day, well below any concern threshold. Even high intakes are self-limited by cyclamate’s taste and mild laxative effects at excessive doses (e.g. some volunteers got diarrhea at extremely high intakes), making it unlikely for people to chronically exceed the ADI in normal use. Overall, regulatory agencies abroad consider cyclamate low-risk at permitted levels, but continue to monitor intake to keep it within safe margins. Technical Evidence: The safety controversy around cyclamate stems from mixed evidence. In 1969, researchers reported that a 10:1 cyclamate-saccharin mixture led to an increase in bladder tumors in male lab rats. Notably, these rodents were fed an astronomically high dose (equivalent to hundreds of cans of diet soda per day), which raises questions about its relevance to human diets. Subsequent studies provided a more reassuring picture: long-term experiments in monkeys (spanning 24 years) failed to demonstrate any cyclamate-related cancers, and multiple epidemiological studies found no increased bladder cancer risk in people who consumed cyclamate-sweetened products. Mechanistically, most ingested cyclamate is excreted unchanged in urine, but intestinal bacteria in some individuals convert a portion into cyclohexylamine (CHA). CHA is the key to cyclamate’s residual risks – it has been shown to cause testicular degeneration in rats at high doses, with a no-observed-adverse-effect level around 100 mg/kg/day in those animal studies. This suggests a potential (though remote) threat to male reproductive health if exposures were extremely high. Importantly, no such effects have been observed at the much lower levels consumed by humans. Studies across several animal species (mice, rats, hamsters, dogs, and monkeys) report that cyclamate does not cause birth defects or general reproductive harm at typical doses. It also has not shown consistent DNA damage or mutagenicity in live animals (some cell-based tests were positive, but in vivo results were largely negative). Major health authorities, including an FDA advisory committee in the 1980s, reviewed the totality of evidence and concluded that cyclamate itself is not carcinogenic to humans. The remaining uncertainty centers on cyclohexylamine’s effects, which led European regulators to apply extra caution. Overall, the evidence indicates that cyclamate poses little to no cancer risk at human-relevant intakes, and any potential reproductive toxicity would require doses far above what consumers encounter. Fast-Food Context: Because of the FDA ban, U.S. fast-food chains and beverage manufacturers do not use cyclamate as a sweetener. Diet sodas, “zero sugar” drinks, and sugar-free desserts in the U.S. instead rely on other sweeteners (such as aspartame, sucralose, or saccharin). In countries where cyclamate is allowed, however, it remains a common ingredient in fountain drinks, flavored syrups, and light desserts. Many international fast-food outlets and beverage brands use cyclamate in combination with other sweeteners to achieve a more sugar-like taste: for example, a blend of cyclamate with saccharin (typically 10:1 ratio) is often used because each masks the other’s aftertaste. Cyclamate is very stable under heat and acidic conditions, so it can be used in baked goods or hot beverages without losing sweetness – a property that some overseas fast-food bakeries and coffee chains take advantage of. Notably, some tabletop sweetener packets in Canada and Europe contain sodium cyclamate, whereas the U.S. versions of those products use alternative sweeteners due to regulatory differences. Consumers traveling abroad might encounter cyclamate-sweetened diet cola, fruit drinks, or soft-serve toppings at international branches of familiar fast-food franchises. In short, cyclamate’s role in fast food is significant outside the U.S., but within the U.S. market it has been replaced by other approved sweeteners. Sensitive Populations / Notes: Certain subgroups could theoretically be more affected by cyclamate. About 7–10% of people are “high converters” whose gut microbiome converts a larger portion of cyclamate into cyclohexylamine. These individuals would have higher internal exposure to the metabolite, which is the source of cyclamate’s reproductive toxicity in animals. Even for these converters, staying within the ADI is considered safe, but it underscores the importance of the intake limits. People with diabetes or those on sugar-restricted diets may consume cyclamate more frequently (e.g. in tabletop sweeteners or diet foods). Health Canada specifically advises that sodium cyclamate tabletop sweeteners be used only under a physician’s advice, reflecting caution for heavy users such as diabetics. Children and pregnant women are generally exposed to very low amounts of cyclamate (since it is not in U.S. foods and only used in specific diet products elsewhere), but regulators still include a safety margin that covers these sensitive groups. Overall, no human population has shown clear ill effects from cyclamate at permitted levels, but those with high intake patterns or unique gut bacteria profiles are considered in safety evaluations as a prudent measure.

We assign the high tier using published research, regulatory guidance, and PRūF’s additive taxonomy. Restaurant usage is derived from public ingredient disclosures and mapped to menu items where this additive appears.