Should you take creatine on rest days?

What creatine actually is

Creatine isn’t a drug, and it isn’t a steroid. It’s something your body makes itself, mostly in your liver and kidneys, and you get more of it from food, mainly red meat and seafood. About 95 percent of it sits in your muscles.

The amounts in food are small, though. A pound of raw beef or salmon has about 1 to 2 grams in it. On a normal diet, your muscles’ creatine store sits at around 60 to 80 percent of what it can hold, and taking creatine as a supplement is how you fill up the rest.

It’s also one of the most researched supplements there is, with more than a thousand studies behind it. That will matter when we get to whether it’s safe.

What it does: your mana bar

The way I usually explain it is with a mana bar. When you do a set, you’re spending mana: every rep takes a little energy out of the bar.

That bar has three parts, and they all work at the same time, but they aren’t built the same. The first part runs on creatine. It’s the fastest and the most powerful, and in the first few seconds of an all-out effort, like the opening reps of a heavy set, it does most of the work. It’s also the smallest, so it drains quickly, which is part of why a hard set gets hard so fast. The other two parts are slower, but they hold more. And like mana, the fast part refills while you rest between sets.

Taking creatine makes that fast part bigger. With more in it, you can squeeze an extra rep or two out of a set, or handle a little more weight, before you run low. One extra rep doesn’t sound like much. Over weeks of training, though, those reps add up to more total work, and more work is what makes you stronger.

So keep your expectations honest. Compared with training without it, creatine gives you a modest edge: a bit more strength and a bit more muscle over a few months of training, with no extra fat. The training still does the work. Creatine helps you do a little more of it. We recommend it to anyone who trains, including people who are just starting.

Why it’s a daily thing

This is the part that answers your question. Creatine builds up. One scoop doesn’t fill the store. The store fills over days or weeks of taking it, and it’s the full store that helps you in the gym.

Once it’s full, it doesn’t stay full by itself. Every day, around 1 to 2 percent of the creatine in your muscles breaks down and leaves your body in your urine. That’s a slow, steady process, and it doesn’t take the day off when you do. Your diet and your body make some of it back, and your daily scoop covers the rest.

Your muscles also keep taking creatine in on rest days. So a rest day isn’t a day off from creatine. The scoop you take on a Sunday is doing the same job as the one you take on a Monday: keeping the store full for the next time you lift. However many rest days your week has, they count.

So what do you do on a rest day?

Take the same amount you’d take on a training day, at whatever time you’ll remember. On training days, people often wonder whether to take it before or after their session, the same question people ask about a protein shake. Even there, the research hasn’t found a clear best time for creatine. On a rest day there’s no session to time it around, so the best time is the one you won’t forget.

Taking it with a meal is an easy way to make it a habit, and there’s a small bonus: food with carbohydrate in it, or carbohydrate and protein, may help your muscles hold on to a bit more of it. That’s a bonus, not a rule.

What if you miss a day?

Honestly, nothing. Not anything you’d ever notice.

Even if you stopped taking creatine completely, your muscles would take about four to six weeks to drift back to where they were before you started. One forgotten day, or a weekend away, doesn’t move that in any way that matters.

So just take your usual amount the next day. Don’t double up to make up for it. The store doesn’t need catching up, and a big single dose, like 10 grams in one go, can be more likely to upset your stomach than the same amount split in two.

What if it’s in your pre-workout?

One thing people sometimes get wrong is thinking their pre-workout has them covered. Plenty of pre-workouts have creatine in them, so it feels handled. But only about half of the best-selling ones list any at all, and those that say how much average around 2 grams a serving, less than the usual 3 to 5 grams a day. And you don’t take a pre-workout every day, or before every session. Honestly, you shouldn’t. So the creatine you get that way comes in small amounts, on some days and not on others.

If that’s what you’ve been doing, it may not have been wasted. When researchers have given people creatine only on their training days, in bigger amounts than a pre-workout holds, it still made them stronger than a placebo did. Whether that works as well as taking it every day hasn’t been properly tested yet, and from a pre-workout you’re probably getting much less than those studies did.

The simple fix is a scoop of plain creatine every day, rest days included. Creatine monohydrate is the kind almost all of the research uses, it’s cheap, and no other form has done better.

How much should you take?

The usual recommendation is 3 to 5 grams a day. That’s kind of the consensus. But honestly, I think it’s smarter to look at how much you weigh. The more muscle you carry, the more creatine your body goes through each day, and bigger, more muscular people may need more than 5 grams just to keep their store full.

The guideline by weight is about 0.1 gram per kilo of body weight a day, or a gram for every 10 kilos (22 pounds). If you weigh 70 kg (155 lb), that’s about 7 grams. At 100 kg (220 lb), it’s about 10, and at that amount it’s worth splitting into two servings, because a single 10-gram dose can be more likely to upset your stomach than two 5-gram ones.

Going above 5 grams hasn’t been shown to bring bigger gains on its own, though. The point of the extra is to keep a bigger store full.

Starting out: should you load?

When you first start, your store isn’t full yet, and there are two ways to fill it.

The slow way is to take your daily amount from day one. It takes about four weeks to fill up, and after that you just keep going.

The fast way is called loading: about 20 grams a day for five to seven days, split into four servings of around 5 grams, and then down to your daily amount. That fills the store in about a week.

Both get you to the same place. Loading just gets you there sooner, and it’s also the week the scale tends to jump. As the creatine moves into your muscles, they hold on to extra water, about half a liter to a liter, which can show up as a pound or two on the scale. That’s water in your muscles, not fat, and it’s one of the everyday reasons your weight moves around. If you’d rather skip that, or you’re in no hurry, the slow way is a perfectly good choice.

Is creatine dangerous?

Some people worry that creatine is dangerous, often because they’re not sure what it is. Now you know: it’s something your body already makes and you already eat.

For healthy people at the amounts on this page, the research hasn’t found it doing harm, and that’s across more than 30 years of studies, some of them following people for years. That includes the kidneys, which is the usual worry. The one side effect that comes up again and again is weight gain, and early on, that’s mostly the water you just read about.

You might also have heard that it makes your hair fall out. That goes back to one small study from 2009 that found a rise in a hormone linked to hair loss in men, without ever looking at anyone’s hair. When a trial finally did measure hair, after 12 weeks of 5 grams a day, there was no difference from a placebo.

There’s really nobody I’d tell not to take creatine. If you’re unsure whether it’s right for you, check with your doctor first.

What happens if you stop?

The creatine goes, but what you built with it may stay. Over four to six weeks, the extra creatine drains out of your muscles, and so does the small edge it gave you in your sets. The strength and muscle you built by training may not go with it, as long as you keep training.

Does creatine do anything else?

The strength and muscle edge is the part that’s well established. Beyond it, the research is younger. In older adults, creatine with strength training seems to build more muscle and strength than training alone. And there’s early research on the brain: some studies find a small boost to memory in older adults, and a few suggest it helps when you’re short on sleep. That’s promising, not proven.

You can take creatine even if you don’t train. Just know that on its own, it does little for your muscles. The muscle benefits come mainly from the extra training it lets you do, so for someone who doesn’t train, the brain research is the main reason, and it’s still early.

Putting it together

Take creatine every day, rest days included: the same amount, at any time that suits you.

3 to 5 grams is the usual amount, but I’d go by your weight: about a gram for every 10 kilos (22 pounds), split in two once you’re near 10 grams.

Forgot a day? Take your usual amount tomorrow, and don’t double up.

Getting it from a pre-workout? Don’t count on that. Take plain creatine every day.

Loading is optional. It fills you up in about a week instead of about four, and it’s the week the scale can jump.

Your muscles don’t care what day it is. They only care that you keep the store full.