How Much Protein Do You Actually Need to Build Muscle?

Ask five people in a gym how much protein they need and you'll get five confident, completely different answers. Someone's aiming for 200g a day. Someone else swears by “a gram per pound, that's just the rule.” Someone's mixing a shake so thick you could stand a spoon up in it. Everyone means well. Nobody's quite agreeing.

So let's have a proper look at what the research actually says, and where the sweet spot really sits.

The official minimum wasn't built with a barbell in mind

The UK's official guidance for protein sits at 0.75g per kilogram of bodyweight a day, roughly 56g for the average man. That number does one job: making sure the general population doesn't become deficient. It's a sensible baseline for a fairly sedentary population, but it was never designed with training in mind.

The research backs that up. A major review pooling data from 49 studies and nearly 1,900 participants found that the standard recommended amount of 0.8g per kilogram wasn't enough to fully support strength and muscle gains during structured training. If you're regularly working out, the everyday baseline is a starting point, not the target.

So what's the actual number

Here's where the research gets pleasantly consistent. For people training regularly, sports nutrition experts widely support a range between 1.4 and 2.0 grams per kilogram of bodyweight a day, a figure that shows up across multiple independent reviews rather than being one lab's opinion.

Not sure where you land? Here's roughly what the sweet spot looks like across a range of bodyweights:

Anywhere in your range is genuinely enough. You don't need to chase past the top end.

The fun bit: more protein doesn't mean more muscle

This is the part that surprises most people. That same large review found that once you reach around 1.6g of protein per kilogram of bodyweight, the extra benefit for strength and muscle growth largely plateaus. A separate 2022 analysis landed on almost the same number, finding gains tapered off between 1.5 and 1.6g per kilogram, with little extra benefit above that.

A couple of individual studies make the point nicely too. One found people eating 2.6g per kilogram gained no more muscle or strength than people eating 1.35g, and another found 2.8g per kilogram produced no bigger muscle-building response than 1.8g.

So there's a genuine ceiling around 1.6g/kg. Above that, your body isn't storing up bonus gains for later, it's just treating the extra as regular food.

The underrated trick: spread it out

How you space your protein across the day matters more than people realise. Research consistently shows that spreading protein across three to five meals, at roughly 20 to 40g each, supports muscle maintenance better than concentrating most of it into one big meal.

So one heroic post-workout shake won't make up for barely eating anything for the rest of the day. Muscles respond better to steady, regular check-ins than one big dramatic delivery.

The actual takeaway

If you're training for muscle and strength, use the table above to find your range and aim to land inside it, spread fairly evenly through the day. Go higher if you like, it won't hurt you, but the extra gains mostly stop showing up once you're past the top end.

Which is good news, honestly. It means you don't need a spreadsheet, six shakes, or a personality built entirely around protein. Just a sensible number, spread sensibly, day after day.

It's also exactly why we built Hustle Bar around 18g of protein per bar: enough to genuinely count toward your day, sized to fit in naturally rather than turn eating into a chore.

Sources

•  Morton, R.W., et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. British Journal of Sports Medicine.

•  Jäger, R., et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition.

•  British Nutrition Foundation. UK Reference Nutrient Intake guidance for protein.

•  Meta-analysis on protein intake thresholds for muscular strength and mass. (2022). Sports Medicine.