One shows the first known example of Iron Age hair gel, experts say. The other wore manicured nails and stood 6 feet 6 inches (198 centimeters) tall.
Discovered in peat bogs in central Ireland, the well-preserved human remains were unveiled this month in Dublin.
Researchers say the men were probably wealthy, well-connected individuals. Living well over 2,000 years ago, both were tortured and killed while in their early 20s, possibly as ritual sacrifices.
The bodies were uncovered by accident in 2003 at separate commercial peat workings just 25 miles (40 kilometers) apart.
Peat wetlands in northwest Europe are well-known for their bog bodies. The wetlands provide cold, acidic, oxygen-free conditions, which prevent decay and mummify human flesh.
The two new Irish bog men were named after the places where they were found: Croghan Hill and Clonycavan.
Oldcroghan man was preserved so perfectly that his discovery sparked a police murder investigation before archaeologists were called in.
Radiocarbon dating showed that he lived between 362 B.C and 175 B.C., while Clonycavan man dates from 392 B.C. to 201 B.C.
A team lead by researchers at the National Museum of Ireland studied the two bodies. The scientists say the fingerprint whorls of Oldcroghan man are as clear as any living person's.
"He had very well manicured nails, and his fingertips and hands were indicative of somebody who didn't carry out any manual labor. So we presume he came from the upper echelons of society," said Isabella Mulhall, the museum's Bog Bodies Project coordinator.
"He had no scars on his body, either—just the equivalent of two small paper cuts to one of his hands," she added.
Although Oldcroghan man is missing his head and lower limbs, the team estimates his height at six feet six inches (198 centimeters), based on his arm span.
"That was a shock to us," Mulhall said. "He's probably the tallest bog body known from Europe."
Had the two bog men met, Oldcroghan man would have towered over Clonycavan man, who measured just 5 feet, 2 inches (157 centimeters) tall.
Perhaps to compensate for his short stature, Clonycavan man coiffed up his hair using an early hair gel.
"Naturally enough, he wanted to make himself look grander," Mulhall said. "It's a bit like someone wearing platform shoes."
Analysis of the substance by archaeologist Stephen Buckley from the University of York in England showed the gel was made of vegetable plant oil mixed with resin from pine trees found in Spain and southwest France.
The study team says the hair product is evidence of Iron Age trade across Western Europe.
While both bog men appeared to be aristocratic dandies of their day, they still met horrible deaths.
Oldcroghan man shows signs of cruel torture before he was beheaded.
"He was stabbed, his nipples were sliced, and he had holes cut in his upper arms through which a rope was threaded in order to restrain him," Mulhall said. He was also cut in half across the torso.
Meanwhile, Clonycavan man suffered three axe blows to the head, plus one to his chest and was also disemboweled.
"There was definitely an attempt to use several different methods to traumatize and torture the men," Mulhall added.
Similar evidence of grisly murders has been seen in other bog bodies found in Britain, Denmark, Germany, and the Netherlands.
For instance, Lindow man, displayed at London's British Museum, was struck twice on the head, garroted, and had his throat slit from ear to ear.
Various explanations have put forward for such bogland killings. These include punishment for breaking ancient codes of honor.
In the case of the two Irish bog men, the study team says they were probably used as sacrifices to pagan gods.
Ned Kelly, keeper of Irish antiquities at the National Museum of Ireland, suggests the bodies were offered to fertility gods by kings to ensure a successful reign. The victims were possibly political hostages.
Kelly says the bodies were placed on the borders of tribal boundaries "to ensure a good yield of corn and milk throughout the reign of the king."
More than 35 scientists worked on the Bog Bodies Project, which also revealed that Oldcroghan man's last meal consisted of buttermilk and cereals.
"We got a good overall account of these people both during their lives and at their deaths," Mulhall said.
The bog bodies will go on display at the National Museum of Ireland in Dublin in May this year.
Details of the finds are outlined in a television documentary to air on the BBC in Britain this Friday.