Mark Skevington's eyesight and energy levels have improved and he now shoots more thar and deer in the South Island hill country than before.
And he puts it down to pig cells being poured into his stomach.
Mr Skevington is one of a handful of New Zealanders taking part in trials for a new treatment for diabetes.
The Christchurch man, who was in Invercargill visiting his parents at the weekend, said the treatment had helped his eyesight improve, his energy levels rise and his hunting trips reap more animals.
The trials he is taking part in are being run by Living Cell Technologies, which breeds the Auckland Island pigs at its unit near Invercargill.
The pigs cells are inserted into patients, where it is hoped they will release insulin in the right amounts.
Mr Skevington had pig cells inserted into his stomach nine months ago and he reports no side effects.
"In fact I have got benefits from it," he said.
"The biggest thing I noticed when I got home was my eyesight was a lot clearer. I can see thar and deer on the hill now, whereas I used to struggle."
The 56-year-old has been a type-1 diabetic for 34 years, during which time he has been taking insulin. He still takes insulin but, since the operation, less of it, and he can now put in more hours walking up the hills on his hunting trips, and he experiences fewer "lows", he said.
He will undergo a series of tests in another three months to gauge progress, and hopes to keep participating in the human trials.
"It's not perfect but they are definitely on the right track," Mr Skevington said.
He met Invercargill Mayor Tim Shadbolt, a strong advocate of the pig cell treatment, while in Invercargill at the weekend.
"If it wasn't for what you people did down there [in Invercargill], I wouldn't be able to participate in the trials, and that would mean the kids I see who suffer from type-1 diabetes wouldn't benefit from this type of work," he said.
Living Cell Technologies announced last month it had enrolled its first two patients into the Phase 2 diabacell clinical trial in Argentina.
