Despite promises to give you a gym-honed physique, some protein shakes lack the ingredients necessary to tone muscles, new research reveals.
Although favoured by Instagram-posting celebrities, popular branched-chain amino acids (BCAA) supplements are not all that effective for muscle growth, a study found.
Yet, taking a whey-based formula doubles a user's muscle response, the research adds.
Study author Professor Kevin Tipton from the University of Stirling, said: 'Athletes interested in enhancing muscle growth with training should not rely on these BCAA supplements alone.'
Sales of such shakes are booming — the sports nutrition market was worth £650 million last year, a rise of 23 per cent on the previous 12 months.
Glamour model Lindsey Pelas frequently praises protein shakes for her figure in her posts
Lowering weights has greater benefits than lifting, a study revealed in May.
Training with heavier loads while lowering weights gains greater strength than using the same weight for both lifting and lowering, the study found.
This may be due to the greater mental effort required to control the body while lowering weights, leading to an increase in leg muscle activation, the research adds.
Study author Dr Simon Walker from the University of Jyväskylä in Finland, said: 'Humans have a greater ability to produce force when lowering a load