Kim Kardashian’s new caffeine-free energy drink relies on paraxanthine – here’s what the science says

Kim Kardashian has launched an energy drink. Instead of containing caffeine, Update includes paraxanthine, a compound the body naturally produces when it breaks down caffeine. According to the brand’s promotional material, using paraxanthine directly “eliminates the crash, jitters and overstimulation” often associated with traditional energy drinks.

Energy drinks are already a huge global market, and most rely on caffeine to provide their stimulant effects. This new product takes a different approach by skipping caffeine and using one of its natural breakdown products instead.

It does not rely on paraxanthine alone. The formula also contains other ingredients commonly used in energy drinks and supplements, including alpha-GPC, sometimes marketed for cognitive performance, and sucralose, an artificial sweetener found in many low or zero sugar beverages. Any assessment of its potential health effects therefore needs to consider these ingredients as well.

Paraxanthine is the main metabolite produced when the body processes caffeine. The liver converts caffeine into three compounds: paraxanthine, theobromine and theophylline. Of these, paraxanthine is the most abundant, accounting for more than 70% of caffeine metabolism, while the other two make up the remaining 20 to 30%.

Caffeine works mainly by blocking adenosine receptors in the brain. Adenosine builds up during the day and promotes tiredness. When those receptors are blocked, we feel more alert. Paraxanthine appears to act on many of the same biological pathways, which may explain its similar stimulant effects.

Some research suggests it may be less toxic than caffeine. Scientists often compare toxicity using LD50, or “lethal dose 50”, the amount required to kill 50% of animals in a study.

In rats, paraxanthine has a higher LD50 than caffeine at around 830 milligrams per kilogram of body weight, while caffeine’s is roughly 300mg per kilogram. In other words, much higher doses are required to reach lethal levels in these animals.

What do animal studies show?

In one long-term study, rats were given either paraxanthine or caffeine for 90 days. Those receiving caffeine showed several signs of overstimulation, including excessive grooming, increased activity and more frequent defecation. Animals given paraxanthine behaved much more normally.

It also appeared less likely to trigger anxiety-like behaviour in rats.

The same study examined biochemical changes after long-term treatment. Rats given caffeine showed increased cholesterol levels and reduced thyroid hormone levels, suggesting a less favourable metabolic profile.

Post-mortem examinations revealed further differences. Several organs were smaller in the caffeine-treated rats, including the spleen, heart, kidneys, liver and testes. These changes were not observed in animals given paraxanthine.

What about human studies?

Animal experiments can provide useful clues, but they do not always reflect what happens in people.

The available human evidence suggests a similar pattern. In one comparison, caffeine produced a greater increase in blood pressure than paraxanthine at comparable doses.

In another study, participants taking paraxanthine performed better in several cognitive tests designed to measure attention and memory, without significant side-effects.

In a small placebo-controlled study, around a dozen healthy adults took it daily for one week. Researchers found no clinically significant changes in standard blood chemistry markers or reports of adverse side effects. However, the study was short and involved a small number of participants, so it cannot establish long-term safety.

It has also attracted interest for potential medical uses and has been patented as a possible treatment for certain psychiatric conditions. That does not necessarily mean it will become an approved therapy.

Taken together, these findings suggest it may produce some of the stimulant effects associated with caffeine, such as improved alertness and concentration, while potentially causing fewer side-effects such as jitteriness or rapid heart rate.

However, an important limitation is that most research comes from studies examining caffeine metabolism rather than people consuming paraxanthine directly. Human trials of the compound itself remain relatively small and short.

What about the other ingredients?

Several additional compounds are included, but the only one for which the dose is clearly stated is alpha-GPC, at 315mg per can.

Alpha-GPC, short for alpha-glycerylphosphorylcholine, occurs naturally in foods such as fish, meat, milk, eggs, cereals and peanuts. After consumption, it is converted into phosphorylcholine, which helps support the production of neurotrophic factors. These proteins help nerve cells grow, survive and communicate.

It has been widely studied for safety. Animal studies using very high doses have found only minor adverse effects, suggesting it is generally considered safe when consumed within typical supplement ranges.

The formula also contains L-theanine, an amino acid found naturally in tea, which may promote a calmer form of alertness and reduce overstimulation.

Another ingredient is sucralose, used in many low or zero-sugar drinks. It is widely regarded as safe by food safety regulators. Some studies have raised questions about possible metabolic effects.

For example, one recent study found that long-term consumption was associated with insulin resistance in mice fed a high-fat diet. Animal findings do not always translate directly to humans, and the amount included in the drink has not been publicly disclosed.

Is paraxanthine better than caffeine?

Each 350ml can contains 300mg of paraxanthine and 315mg of alpha-GPC. That amount is broadly comparable to the quantity the body might generate after metabolising a large dose of caffeine, although the exact conversion varies between people.

Based on the available studies, this level would likely produce stimulant effects similar to caffeine, such as increased alertness and improved attention. Some evidence suggests it may cause fewer of the side-effects often linked to caffeine, including jitteriness or increased heart rate.

The alpha-GPC dose falls within a range generally considered safe and may support brain signalling processes.

The main uncertainty relates to sucralose. While widely approved for consumption, some research suggests that long-term intake could affect metabolic health, although the evidence remains mixed and the quantity here is unknown.

Overall, studies in animals and humans suggest paraxanthine may be less toxic than caffeine and capable of producing similar stimulant effects. However, the evidence base remains far smaller than the decades of research available for caffeine.

More research will be needed before we can determine whether paraxanthine-based energy drinks offer a meaningful advantage over traditional caffeinated options.

Colin Davidson has previously received funding from the US National Institute on Drug Abuse (NIDA). He is a consultant with the Defence Science and Technology Laboratory (UK) and a member of the Advisory Council on the Misuse of Drugs. His views in this article are his own.