Iyogun made his long-awaited return to action last weekend, coming off the bench in the 39-38 Premiership Rugby Cup defeat at Bristol Bears.
It was the 22-year-old's first appearance since suffering an Achilles injury against Exeter Chiefs back in January.
And Dowson was delighted to see Iyogun back.
"He's got a great attitude - he's a brilliant bloke," said the Saints boss.
"It's slightly tougher coming through in the front row, where you have to earn your stripes, and there are some tough lessons there.
"He came in at a time where we threw him in at the deep end and he was very, very strong. It says a lot about his character and his confident to go into that situation and perform.
"It was down at Exeter (in a Champions Cup quarter-final clash in September 2020) where he really earned his stripes and became a bit of a legend among the senior group, and from then on he's got bigger and better every year.
"Obviously having nine months out with an Achilles injury is tough, but the way he applied himself to get into the sort of shape he's in now has meant that nine months has in no way been wasted or spent dwelling on the past, it's all been focusing on how he can get better.
"That growth mindset is incredibly positive and we're all impressed with how he's applied himself in those nine months.
"I thought he played brilliantly at the weekend."