She failed an in-competition test after winning the women's 53kg competition on Friday, testing positive for banned diuretics and masking agents.
Amalaha has been provisionally suspended from the Games, CGF chief executive Mike Hooper said in a statement.
"The athlete's A sample was found to contain both amiloride and hydrochlorothiazide, both prohibited as diuretics and masking agents under class s5 of Wada's Prohibited List," he said.
"Ms Amalaha has pursued her right to have her B sample tested, which will take place at the accredited laboratory in London on July 30."
Amalaha was Nigeria's first gold medal winner in Glasgow, equalling the Games snatch record of 82kg with her first attempt before reaching 85kg on her third.
Her combined total of 196kg was also a Games record, and according to the International Weightlifting Federation she is the youngest women to win a weightlifting title in Games history.