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.

How Do I Take Creatine?

If you’re a creatine virgin, the first step is to flood your muscles with PC. “This is called a ‘loading protocol’,” says Bean. For the first week, she suggests you mainline 0.3g of creatine per kg of bodyweight. For a 70kg guy, that translates to around 21g every day. Because your body can only absorb small amounts at a time, split this into four equal servings to avoid literally pissing your money away.

Once your muscle-building silos are stocked, you can cut back. “Three grams a day is the minimum, but I recommend about 5-8g per day depending on your body size, diet and goals,” says Price. Unlike other proteins, your body stores creatine well, so you don’t need to time your supps. “Just make sure you have it daily. Morning or before bed is easiest as you’re – usually – at home.”

What’s The Best Source Of Creatine?

To hit that 8g sweet spot, you’d need to put away close to 2kg of steak a day. Good for your gains, less so for your wallet and bowels. Supplements provide purified creatine monohydrate, which you can mix with water for an easier-to-stomach route to muscle. It’s also best to stick to the simplest stuff. “The are lots of ‘new and improved’ creatines out there,” says Price, “but plain old creatine monohydrate is the original and still the best.”

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Is Creatine Safe?

According to more than a century of research, absolutely. “It is the most heavily studied ‘ergogenic’ in the world of sports nutrition,” says Price. “Yes it is safe and no, it is not a steroid.” Its only side effects are positive – you’ll perform at a higher level, particularly in activities that require short bursts of intense energy, says Bean.

“If you train with weights or do any sport that includes repeated sprints, jumps or throws – such as rugby and football – creatine supplements may help increase your strength, muscle mass and performance.”