Polyjuice Potion

Polyjuice (Pottermore illustration)

**Polyjuice Potion** is a potion which, when drunk, modifies the drinker's appearance so that they resemble another person. Typically, this effect lasts for only an hour (see *Modified Polyjuice*).

## Function

The Polyjuice Potion's base recipe contains the general pattern of the magic, but the specific person that one will change into is determined by one variable input: the hair (or fingernail or blood) of the person whose appearance you will transform into. The reason it works is because the hair not only contains DNA but also the witch or wizard's magical signature, which is regularly absorbed by their hair. The potion doesn't replicate every part of the signature, only the physical part.

The Polyjuice recipe is extremely well-balanced and magically complete. This means that, once finished, it is stable enough to accept the variable of a hair without reacting. It has a natural shelf life of several months.

## Modified Polyjuice

In the summer after Harry Potter's first year, she developed a variation of Polyjuice that allowed for a person to transform into another for an extended period of time. This subject had been researched previously, though a documented solution did not seem to exist. By adding a pea-sized amber stone to the cauldron while preparing the potion, Harry was able to increase the time the potion would last for almost a year. She suspected that the reason it hadn't been seriously studied was because such a small amount would increase the time by so long. Unlike typical Polyjuice, Modified Polyjuice goes bad soon after it's finished due to the interactions of the natural magic of amber and the other ingredients.

Harry also discovered a spell which blended the hairs of two people, intended to be used for couples so that they could see an approximation of what a prospective child would look like. Using this, she blended her own hair with Archie's, once for a girl and once for a boy. This caused them to look nearly the same as each other, with only slight differences to their original appearances.

## Uses

* **The Pureblood Pretense: Chapter 1:** Used by Harry and Archie to turn into each other for a short period of time to fool their families and allow them to go to the opposite school. Stolen from the Auror kit of James Potter.
* **The Pureblood Pretense: Chapter 15 and 16:** Used by Harry and Archie to turn into each other for a short period of time so that they could go home for Christmas break. Enough for a day was stolen from Professor Tallum's seventh-year Potions class by Archie and Hermione.
* **The Pureblood Pretense: Chapter 21:** Used by Harry to turn into Archie so that she could meet Sirius and return home. (Presumably also used by Archie)
* **The Serpentine Subterfuge: Chapter 1:** Used by Harry and Archie to turn into each other; Harry so that she could leave to attend the Malfoy Garden Party, and Archie so that he could leave to visit Hermione. Also used at the end of their visits so that they could switch back in Diagon Alley.
* **The Serpentine Subterfuge: Chapter 3:** Used by Archie to turn into the Harry-Archie blend. Brewed by Harry over the summer.
* **The Serpentine Subterfuge: Chapter 3:** Used by Harry to fool Sirius on her way back to Hogwarts. (Presumably also used by Archie)
* **The Serpentine Subterfuge: Chapter 3:** *(Modified Polyjuice)* Used by Harry and Archie to transform into the Harry-Archie blend for their second year.
* **The Serpentine Subterfuge: Chapter 10 and 12:** Brewed by Harry under the direction of Severus Snape. (No use stated)
* **The Serpentine Subterfuge: Chapter 14:** *(Modified Polyjuice)* Used by Harry and Archie to transform into an updated version of the Harry-Archie blend for the summer. Brewed by Harry in her Hogwarts lab.
* **The Ambiguous Artifice: Chapter 6:** *(Modified Polyjuice)* Used by Harry and Archie to transform into an updated version of the Harry-Archie blend for their third year.
* **The Ambiguous Artifice: Chapter 12:** *(Modified Polyjuice)* Used by Harry to resume the last version of the Harry-Archie blend after aging prematurely. Brewed in a series of hotels away from Hogwarts.
* **The Ambiguous Artifice: Chapter 15:** Used by Harry to temporarily transform into the updated Harry-Archie blend so that she could memorize how it looks for a glamour, until she could brew the next batch of Modified Polyjuice.
* **After The Ambiguous Artifice: Chapter 15:** *(Modified Polyjuice)* Used by Harry to transform into an updated version of the Harry-Archie blend for the summer. (Archie did not take it.)
* **The Futile Facade: Chapter 4:** *(Modified Polyjuice)* Used by Harry to transform into the same version of the Harry-Archie blend for her fourth year.
* **The Futile Facade: Chapter 10:** *(Modified Polyjuice)* Unused batch created by Harry in case the Animagus Revelation potion cancelled it out.

## Trivia

* In *Harry Potter* canon, you can Polyjuice into Muggles, as Harry and Hermione did more than once in *Deathly Hallows*. It is unclear whether this is also the case in *Rigel Black* canon due to the explanation given about magical signatures absorbed by a wizard's body.
* Muggles can transform into witches or wizards. The idea of transforming a random, unsuspecting Muggle child using Polyjuice to see what a couple's child would look like, then Obliviating him afterwards, is suggested in a medieval-era book.
* It's considered taboo to Polyjuice into someone of the opposite sex. Partially because of this and partially because of the risk to the reproductive organs involved, the long-term effects of transforming into the opposite sex are not documented.
* While under the effects of Polyjuice, the drinker can still feel phantom pain even if the effects are not apparent on their physical body.
* The Checking Charm, a charm used by Healers, can be used to detect the use of Polyjuice.
* Polyjuice is considered one of the "Big Five", a nickname for the potions which most intrigue witches and wizards. The other four are Amortentia, Wolfsbane, Draught of Living Death, and Felix Felicis.

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 The Serpentine Subterfuge: Chapter 3
2. ↑ 2.0 2.1 The Pureblood Pretense: Chapter 16
3. ↑ 3.0 3.1 3.2 The Serpentine Subterfuge: Chapter 2
4. ↑ 4.0 4.1 The Ambiguous Artifice: Chapter 15
5. ↑ The Futile Facade: Chapter 4
6. ↑ 6.0 6.1 The Serpentine Subterfuge: Chapter 13
7. ↑ The Ambiguous Artifice: Chapter 5
8. ↑ The Ambiguous Artifice: Chapter 4