It was written by Melanie C, Ina Wroldsen and Jez Ashurt, while production was overseen by Andy Chatterley, with Peter-John Vettese credited as a vocal producer.

Reviews of "Weak" were generally positive, with Entertainment Focus stating that it was "one of the highlights from The Sea and finds Melanie on fine vocal form.

A slow-building beat backs Melanie’s distinctive vocals as she sings about being too weak to leave a relationship that is no good for her.

"[2] Ben Weisz from MusicOMH found that "on "Weak," Chisholm simply shouldn’t be attempting Destiny's Child-style belting with her distinctive voice, which just grates as whiney when forced in that direction.

[3] A music video for "Weak" was directed by Michael Baldwin and filmed in a London hotel room.