Starting as soon as this summer, Diet Pepsi will be aspartame free — in stores, at least.

PepsiCo said earlier this year that it would be replacing the aspartame used to sweeten Diet Pepsi with sucralose, another artificial sweetener more commonly known as Splenda. According to CEO Indra Nooyi, though, the formula we’re familiar with will still be available online for those that prefer it.

John Sicher, the publisher of the industry tracker Beverage Digest, thought that making the aspartame version of Diet Pepsi available online would be a smart move for PepsiCo.

“They can tell consumers, ‘if you want the old one, we have it for you,’” he told ABC News.

The change was influenced by customer feedback and, according to ABC News, executives’ concerns that the public’s fears about aspartame were causing sales to decline. Both Diet Pepsi and Diet Coke saw a drop in sales last year, with U.S. diet soda consumption falling 5.9 percent.

Aspartame was discovered in 1965 and approved for use in carbonated beverages in 1983 by the Food and Drug Administration (FDA). Critics have claimed that the initial research and testing of aspartame was flawed, and that various conflicts of interest allowed the substance to be released into the market. Consistent research has been conducted regarding the safety of the artificial sweetener, but according to the FDA, there has been no evidence that provided a reason to believe aspartame is unsafe. Complaints of health problems have circulated since aspartame was released onto the market, but no definitive links have been found.

Sucralose is another artificial sweetener, about 320 to 1,000 times as sweet as regular sugar, and about three times as sweet as aspartame. Sucralose has received slightly less public contempt than aspartame, though both products have yet to be satisfactorily linked to serious health problems.

Artificial sweeteners have also come under fire for less definitive side effects, including increased appetite and cravings.

Regardless of inconclusive studies and research, public opinion has largely shifted away from aspartame in favor of more natural sweetening options. Nooyi assured The Week that the new Diet Pepsi is a “very, very good product,” and that it will be available by late August.