If you’ve ever wondered why your curls aren’t translating to tighter t-shirt sleeves, then odds are you’ve at least thought about trying creatine. It’s touted as the most effective way to build muscle, offering the benefits of the shadier things bodybuilders reach for, without needles or uncontrollable rage. But should you believe the hype? We quizzed two of the UK’s leading sports nutrition experts, for the skinny on the supplement that could stop you being so skinny.

What Is Creatine?

Those concerned about ingesting strange chemicals that promise immediate muscle can rest easy. “Creatine is a protein that is made naturally in the body from three amino acids – arginine, glycine and methionine,” says Anita Bean, a registered nutritionist and author of The Complete Guide to Sports Nutrition. (Related: A Beginner’s Guide To Protein Shakes) Your body builds around a gram of creatine a day. You get double that if you’re carnivorous, says Bean, since “it’s also found in meat and fish.” But those levels won’t enact serious change. For that it also comes purified in supplements.

How Does Creatine Work?

If you consider your biceps like a building site, then most protein supplements are like piles of bricks – after a workout demolishes your old muscle fibres, your body reaches for proteins to build something bigger and better. But creatine is more like upgrading from a hammer to a wrecking ball. “Creatine combines with phosphorous to form an energy-rich compound call phosphocreatine,” says Bean. “This fuels muscles during high-intensity activities, such as lifting weights or sprinting.” The muscle contractions that lift weight are powered by a chemical called ATP; when this fuel is exhausted, so are you. Phosphocreatine helps your body to replenish ATP stores more rapidly. “By consuming more – supplementing – we increase the size of the available energy reservoir in the cell and tissue,” says performance nutritionist Drew Price, author of The DODO Diet. Translation – you can work harder, lift heavier and recover faster. Which means quicker results.