The Extra Strength Tylenol “Rapid Release gels” package depicts a blue-and-red capsule gushing a cloud of pain-relieving medicine from laser-drilled holes, a visual depiction of relief.

But the gels actually dissolved more slowly than less expensive Tylenol tablets in a laboratory test, according to a study published in the journal Advances in Investigational Pharmacology and Therapeutic Medicine — with the rapid-release gelcaps taking about 30 seconds longer than a tablet of the same dose. The researchers from Valisure, a start-up pharmacy that screens medicines, found a similar effect when they compared rapid-release gelcaps to regular tablets of generic acetaminophen from Walgreens, Rite Aid and Walmart Equate.

Several outside experts said the laboratory tests don’t raise health or safety concerns. But the finding highlights how difficult it can be for consumers to decipher the claims of over-the-counter drugs — in this case potentially opting to pay more for a form of medicine that’s called “rapid release” but is no faster to dissolve than a tablet.

“This could be a little misleading. People will expect a faster effect after they take this. The dissolution in both formulations is the same,” said Erika Stippler, a principal scientist at US Pharmacopeia, an independent organization that sets quality standards for drug ingredients and supplements.

Overall, the rapid-release gels carried a 23 percent higher price than the tablets, but both forms of the drug dissolved in under eight minutes. Tylenol and generic acetaminophen are frequently used for headaches or pain relief and are responsible for an estimated $350 million in sales each year.

Ernie Knewitz, a spokesman for Johnson & Johnson, the maker of brand name Tylenol, called the study design “an apples to oranges comparison.” The Tylenol gelcaps, he said, have been shown to be “rapid release” in comparison to conventional gelcaps, not to the uncoated tablets that are offered in the equivalent dose.

“TYLENOL Rapid Release Gels are the only over-the-counter pain reliever to feature laser drilled holes specifically designed to release medicine faster than a conventional gelcap. The innovation in these gelcaps requires significant additional manufacturing processes, which is the main factor in the price differential,” Knewitz said.

Peter Strella, a spokesman for Rite Aid, also argued that the study was “not making the right comparison” because rapid-release gelcaps are faster to release than a standard gelcap, not a tablet. A Walmart spokeswoman made a similar argument.

It’s not clear whether consumers reading the packaging understand the comparison being made, because conventional gelcaps aren’t available in the same dose, while the tablet is.

“I do notice that the rapid release do work faster and better than regular caplets,” commented one customer review on the Tylenol website.

“These extra strength rapid release takes half the time normal Tylenol takes to kick in,” wrote another user.

“Although a bit more expensive than the regular release pills, they are worth the purchase to get the pain knocked out within 5/10 minutes, versus the 20/30 minute wait for the original pill form to dissolve and enter your system,” a reviewer on Amazon wrote.

An advertisement for the name-brand version of rapid-release Tylenol says laser-drilled holes in the gelcaps “release medicine fast, for fast pain relief. Fast enough to keep up with you, so that you can keep up with life.”

Valisure funded and carried out the study. Its chief medical officer, David Gortler, is the editor in chief of the journal and recused himself from the review process. David Light, chief executive of Valisure, said the primary reason for the gelcap to take longer to dissolve than the tablet is that the gelcap surrounds a tablet.

He also noted there was a surprising amount of variation between the different versions of the drug.

“If anything was kind of surprising, it’s that there’s a lot of variability in some of these brands; they can be two to three times faster or slower than each other, making these same claims,” Light said.

Sandy Walsh, a spokeswoman for the Food and Drug Administration, said the agency does not comment on specific studies.

There are other reasons consumers might prefer a gelcap to a tablet — they may be easier to swallow or mask the bitter taste of the active ingredient. But consumers in a drugstore aisle may see the words “rapid release” and assume that the drug is faster-acting than the same-dose tablet on the next shelf.

Michael Carome, director of Public Citizen’s Health Research Group, said that while the “rapid release” claim is accurate, it could also be made about the tablets.

“There probably are consumers out there that may believe, upon seeing fast release or rapid release, that might lead to faster pain relief than those products that don’t have that in the name of the product. That’s a misunderstanding,” Carome said. “What the study told me is that both the gelcap formulations and the tablet formulations are immediate release formulations, that they both break down quickly.”

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