Related to this: What would happen if Lupin drank Polyjuice Potion?
If you made Polyjuice Potion from one of Lupin's hairs, and then drank it during a full moon night, would you turn into a werewolf for the hour it was in effect?
Related to this: What would happen if Lupin drank Polyjuice Potion?
If you made Polyjuice Potion from one of Lupin's hairs, and then drank it during a full moon night, would you turn into a werewolf for the hour it was in effect?
Our friend dobby has the right quote:
'I'm sorry Harry, but I had to check,' said Lupin tersely. 'We've been betrayed. Voldemort knew that you were being moved tonight and the only people who could have told him were directly involved in the plan. You might have been an impostor.'
'So why aren' you checkin' me?' panted Hagrid, still struggling to fit through the door.
'You're half-giant,' said Lupin, looking up at Hagrid. 'The Polyjuice Potion is designed for human use only.'
Harry Potter and the Deathly Hallows - p.63 - Bloomsbury - Chapter 5, Fallen Warrior
But my interpretation is different. Lupin completely rules out the possibility that anyone could use the Polyjuice Potion to successfully transform into Hagrid, because it is designed for human use only. It doesn't work with part-giants like Hagrid, and I see every reason to believe it wouldn't work with Lupin either, you would not be able to transform into him, because he is a werewolf.
Werewolves are included in the original Comic Relief version of Fantastic Beasts and Where to Find Them and are explicitly referred to as fantastic beasts. Note also the sentence "humans turn into werewolves only when bitten". Lupin is a werewolf. A werewolf being a human that turns into a wolf at the full moon. He is not only a werewolf at the full moon. He is only a wolf at the full moon. He is a werewolf all the time.
The werewolf is found worldwide, though it is believed to have originated in northern Europe. Humans turn into werewolves only when bitten. There is no known cure, though recent developments in potion-making have to a great extent alleviated the worst symptoms. Once a month, at the full moon, the otherwise sane and normal wizard or Muggle afflicted transforms into a murderous beast. Almost uniquely among fantastic creatures, the werewolf actively seeks humans in preference to any other kind of prey.
Fantastic Beasts & Where to Find Them - pp.41-2 - Bloomsbury
We also see throughout canon Lupin referring to himself as - and being referred to as - a werewolf generally.
'NO!' Hermione screamed, 'Harry, don't trust him, he's been helping Black get into the castle, he wants you dead too - he's a werewolf!'
There was a ringing silence. Everyone's eyes were now on Lupin, who looked remarkably calm, though rather pale.
'Not at all up to your usual standard, Hermione,' he said. 'Only one out of three, I'm afraid. I have not been helping Sirius get into the castle and I certainly don't want Harry dead ...' An odd shiver passed over his face. 'But I won't deny that I am a werewolf.'
Harry Potter and the Prisoner of Azkaban - p.253 - Bloomsbury - Chapter 17, Cat, Rat and Dog
Greyback is also a werewolf - all the time. So I believe once a person is bitten they become a werewolf - a fantastic creature - permanently. And I don't think the Polyjuice Potion will work with them.
Having said that, Kingsley clearly felt the need to check if Lupin was trustworthy:
Hermione flung herself into Harry's arms, but Kingsley showed no pleasure at the sight of any of them. Over Hermione's shoulder Harry saw him raise his wand and point it at Lupin's chest.
'The last words Albus Dumbledore spoke to the pair of us?'
'"Harry is the best hope we have. Trust him,"' said Lupin calmly.
Harry Potter and the Deathly Hallows - p.65 - Bloomsbury - Chapter 5, Fallen Warrior
So it's possible that someone could successfully transform into Lupin, Kingsley seems to believe it's possible. But then, maybe he wasn't really thinking it through in the heat of the moment.
TL;DR It's unclear, in canon Kingsley thinks it's a possibility, which is strong evidence. But I'm just not sure Kingsley's actions under pressure trump what we know about werewolves and Polyjuice.
I don't think it works that way. The person will turn into Lupin even if they took it on full moon as Polyjuice Potion is designed just for humans.
“I’m sorry Harry, but I had to check” said Lupin tersely. “We’ve been betrayed. Voldemort knew that you were being moved tonight and the only people who could have told him were directly involved in the plan. You might have been an impostor.”
“So why aren’ you checkin’ me?” panted Hagrid, still struggling with the door. “You’re half—giant,” said Lupin, looking up at Hagrid. “The Polyjuice Potion is designed for human use only.”
Deathly Hallows, Ch 5, Fallen Warrior
What the last sentence means is one cannot use the potion to turn into a non-human since when Hermione takes it in second year containing cat hair she remains a human but gets some cat features. I guess it can work the same way in case of Lupin. The drinker might transform into Lupin with wolf like features but surely it will not transform the drinker into a full werewolf.