Tuipulotu had been been provisionally suspended after returning a positive drugs test last year and returned home early from the All Blacks' end of year tour.
A statement from New Zealand Rugby says they have now received the results of Tuipolotu's B sample, which showed no banned substance was present.
Tuipulotu's suspension has been lifted immediately and he was free to play for the Blues in the Super Rugby competition which starts later this month.
Tuipulotu said the process had been stressful and is relieved it was over.
"This has been a challenging and difficult time for me, my partner, family and team mates, and I am grateful for their support. I'm pleased the matter is now closed, with my reputation and integrity intact, and I look forward to getting back into training and an exciting year of rugby."
NZ Rugby chief executive Steve Tew welcomed the result.
"This is an important and welcomed conclusion for both Patrick and for rugby. We are pleased that a robust process has been undertaken, and that he has been fully cleared.
"There is no room for doping in rugby, and we take our responsibility to keep the game clean very seriously," he said.
NZ Rugby Players Association chief executive Rob Nichol said they were relieved that the right outcome had been achieved.
"Working with Patrick through the process, we always felt confident that he would be cleared. To be honest, there is an element of frustration, given the initial result and publicity, but at least people now know Patrick did nothing wrong," he said.
Nichol said it was unclear why there had been a discrepancy between the A and B sample results, and they were waiting for an explanation from the testing laboratory in Salt Lake City.
"This result also reinforces the importance of the regulations and strict confidentiality obligations regarding players and their rights. Patrick was unfairly labelled as a result of the premature publicity of this matter. We trust that everyone now has a greater level of understanding in this regard."
Photo: Photosport Patrick Tuipulotu is cleared to play for the Blues.