The new labels, which coincide with the brand's new look, list caffeine as an ingredient and also separately state "caffeine content: 25mg/8fl oz".
The disclosure, which is relevant only to products sold in teh US, comes as consumer and health groups increasingly petition for the clear labeling of caffeine in order to avoid unnecessary risk for vulnerable consumers, such as children and pregnant women.
"We're simply giving consumers more information.
We started phasing these labels in several months ago on many of our beverages.
They're showing up on Pepsi-Cola now because we timed the labelling change to coincide with the brand's new look.
This is something the whole industry has agreed to do," said PepsiCo in a statement.
Under current regulations, the US Food and Drug Administration (FDA) has granted caffeine generally recognised as safe (GRAS) status in cola-type beverages, to a limit of 0.02 per cent.
But the American Dietetic Association – as well as the Food Standards Agency in the UK – advises people not to consume more than 300mg of caffeine per day.
Health Canada advises consumers to limit their caffeine intake to 400 to 450 mg per day.
This advice is particularly aimed at pregnant women, who, studies indicate, have greater risk of miscarriage or babies with low birth weight if they exceed the 300mg barrier.
A study published last year in the Journal of Analytical Toxicology stated that all drinks containing caffeine should display the caffeine content on their labels, to prevent those at risk from consuming too much of the substance.
The research team analysed the caffeine content of 10 energy drinks and 19 fizzy sodas, all widely available.
They found all the fizzy drinks had caffeine levels well inside the 65mg per 12oz serving recommended limit for cola drinks in the US, while most energy drinks had levels in the high 60s and 70s for an 8oz serving.
Dr Bruce Goldberger, one of the researchers, told BeverageDaily.com
he was surprised by the high caffeine content of some of the energy drinks.
He pointed out that only four of the 10 were labelled with some sort of warning to consumers.
"In certain people, consumption of caffeine causes serious health effects, such as anxiety, palpitations, irritability, difficulty sleeping and stomach complaints," he said, urging for the clear labelling of the substance on all products.
For the past decade, the US consumer advocacy group Center for Science in the Public Interest (CSPI) has been calling on FDA to require the disclosure of caffeine content on food labels.
The group yesterday backed PepsiCo's decision to change its labels, and called on rival Coca-Cola to follow suit.
"The Center for Science in the Public Interest and the American Medical Association have urged the FDA to require soft drink and coffee makers to list caffeine content on labels," said CSPI yesterday, in a letter to Coca-Cola's president and chief operating officer, Muhtar Kent.
"Until FDA acts, we believe that every food company whose foods contain caffeine, whether it occurs naturally or artificially, should disclose milligrams of caffeine voluntarily.
In addition to helping some consumers avoid caffeine, disclosure may help those of your customers who wish to seek it out," it added.
Following PepsiCo's example could allow food and beverage manufacturers to prevent future regulatory concerns.
BeverageDaily.com sister site, FoodNavigator-USA.com, will next week hear from lawyers specializing in the food industry why caffeine is an issue of rising importance, and what manufacturers can do to protect themselves from imminent regulatory action.