Gakpo joined Liverpool from PSV Eindhoven for £44m in the January transfer window after impressing for the Netherlands at the 2022 FIFA World Cup in Qatar.
The 23-year-old also impressed for PSV in the first half of the season, scoring 13 goals and providing 17 assists in 24 appearances.
Gakpo's move to Liverpool has coincided with a poor run of form for Jurgen Klopp's side, who have won just once in seven attempts since the World Cup.
Gakpo has failed to score or assist in six games for the Reds so far.
Speaking on a YouTube show hosted by former Netherlands international Andy van der Meyde, Koeman compared Gakpo's situation to that of Ryan Gravenberch, who has also failed to set the world alight since joining Bayern Munich from Ajax.
"The level in England is higher than in the Netherlands, but they are also young boys, aren't they? Like Gravenberch going to Bayern and not playing. Then that is difficult," Koeman said.
"You can see that he has ended up in a team that is not doing well. Then it becomes more difficult for him, as a new signing. You are tested right away.
"And if you don't score or you're not important and you don't win any matches, it's very difficult, especially for a young player. If that was someone aged 28 with experience, it would be different."
