In example, a habanero pepper normally has 100,000 Scoville heat units, whereas Pepper X has 2.69 million.
Ed Currie, a breeder and grower, created both record-breaking peppers.
Pepper X pods and seeds will not be sold since they are a proprietary pepper.
Mr Currie grew Pepper X on his South Carolina farm for a decade, but kept his project under wraps to safeguard his intellectual property.
"This was a team effort," said Mr Currie in a statement. "We knew we had something special, so I only let a few of my closest family and friends know what was really going on."
Pepper X registered an average of 2,693,000 Scoville Heat Units (SHU) in lab tests at Winthrop University in South Carolina,
It is over a million SHU hotter than Mr Currie's previous invention, the Carolina Reaper, which averaged 1,641,183 SHU.
The Scoville Scale, established by pharmacist Wilbur Scoville in 1912, measures how many times capsaicin must be diluted.