How to use the blood reinvigoration spell?

[Viajero]

I see it is listed with 100 fatigue but the result is to reset it at zero... is there any point therefore in listing a fatigue figure for this spell?

In other words, if my mage is blood 1 (required for this) and has 99 fatigue, can it cast the spell? if casted in this case, will the fatigue be really zero afterwards?

[Gregstrom]

I think it goes something like: Fatigue is resest to zero, but then fatigue for casting Reinvigoration gets applied. So it's pretty great for mages with B3+, but little use for B1 mages.

[llamabeast]

100 fatigue also means that a blood slave is used, which is important.

[Baalz]

Nah, its effect goes after the fatigue you get for casting it (mostly...maybe encumbrance fatigue is kept? Seems like you have a little bit of fatigue left)

Great for:
Communions (effects all slaves)
Thugs/SC - cast 4 high fatigue buffs then Reinvig to go into melee with almost no fatigue.
Pimping mages - Script something like summon imps, reinvig, summon imps, reinvg, summon imps. Oooor.... Thuderstrike, Thunderstrike, reinvig, Thunderstrike, reinvig (thunderstrike, thunderstrike).