The Meth Lab received mixed reviews from music critics. At Metacritic, which assigns a normalized rating out of 100 to reviews from mainstream critics, the album received an average score of 59 based on 11 reviews, which indicates "mixed or average reviews".[3] David Jeffries of AllMusic gave the album three and a half stars out of five, saying "Uncle Murda, Streetlife, and Hanz On appear often, making this LP close in structure to the crew-focused Theodore Unit releases from Ghostface, but that's not a complaint as much as a caution. Consider this a Meth-led posse LP aimed at returning fans, and a very good one at that."[4] Paul Cantor of Billboard said, "Method's skill and charisma are by far the highlight of The Meth Lab, but there's not enough of him to make this unremarkable compilation pop."[5] Del F. Cowie of Exclaim! stated, "Too often, the album is weighed down by pedantic, average beats and too many run of the mill guest verses, indicating Meth's generosity is a bit of a weakness. Ultimately, it dilutes The Meth Lab's potency."[7] Andrew Gretchko of HipHopDX said, "The Meth Lab may be Method Man’s return to solo work, but without a true connection between the tracks the album feels more like a mixtape than an album, a string of songs that range from uninspiring to a reminder that Method Man was once one of Hip Hop’s elite."[8]