Creatine Guide: What It Is, How It Works, Proven Benefits And The Truth On Side Effects

Fact of the day: creatine is one of the most-researched fitness supplements on the market. And practically all of that research is positive: after an analysis of several existing studies on creatine, the International Society of Sports Nutrition (ISSN) declared that ‘creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes with the intent of increasing high-intensity exercise capacity and lean body mass during training.’

It’s not just athletes that reap the rewards, either. You and I can both benefit from taking it, particularly as females. Women have naturally lower creatine stores than men. We respond better to creatine supplementation and could experience double the performance improvement than males. Besides performance and muscle growth, creatine can also work wonders for PMS symptoms, and feeling your fittest and healthiest self during pregnancy, postpartum and menopause.

All that said, there’s a little more to it than popping some powder into your protein shake or taking a pill as a pre-workout, and none of you should ever consider putting anything into your body without knowing exactly how and when to take it, and whether what you’re taking is legit. So, we turned to some of the smartest minds in sports supplementation to talk you through the key facts, while breaking down the myths. Spoiler: it won’t cause weight gain, and your kidneys won’t crumble.

What is creatine?

In layman’s terms, it’s an ‘amino acid stored in your muscles, brain and gut, and is required for all of the body’s fast, high-energy and demanding activity,’ Dr Stacy Sims, a female physiologist and nutrition scientist, explains.

‘It’s a naturally-occurring compound and your body produces under 1g per day in your liver, after you eat protein.’

It can be obtained through your diet via animal protein, especially red meat and fish, but you’d need to eat inhuman amounts to hit the level available in most supplements available to buy.

What foods are high in creatine?

  • Beef
  • Pork
  • Salmon
  • Chicken
  • Venison
  • Cod
  • Tuna

What does it do?

If you’re considering trying creatine, it can help to know how it actually works. Your body has three main energy systems: the aerobic, anaerobic and the APT-phosphagen system. All of these systems use a molecule called ATP (adenosine triphosphate) to carry and release energy.

During intense bursts of activity, like HIIT workouts, the ATP-phosphagen system is activated and your body generates energy (in the form of ATP) from another molecule called phosphocreatine (PCr). ATP is broken down and energy is released. PCR is what your body needs to replenish ATP (i.e. energy) levels. But you only have a very small amount, which is where creatine supplementation comes in. Props to anyone who’s still with us; promise the next sections aren’t so science-based.

What are the benefits?

1. Creatine improves exercise performance

In one study in 2016, female participants experienced a 15% increase in exercise performance after supplementing with creatine for 10 weeks, compared to just 6% in men – more than double the benefit. Dr Sims says various mechanisms are at play here:

One is that you will have a greater energy availability through increased ATP turnover during exercise, but you’ll also have delayed neuromuscular fatigue.’

You’ll get tired less quickly and be able to go for longer, basically.

2. Creatine increases muscle mass and strength

Another number for you: 95% of all creatine is stored in your skeletal muscles. So, it makes sense that supplementation can help you gain strength and increase muscle growth.

How? As well as support for the ATP energy system mentioned above (meaning you’re capable of carrying out more intense workouts and lifting heavier), creatine has been shown to promote muscle gain by drawing water into the muscle, increasing levels of a hormone called IGF-1 (which increases muscle growth) and improving your performance ability and recovery. This has been so well proven that the European Food Safety Authority (EFSA) now recommends creatine supplementation alongside strength training for improving muscle growth in adults over the age of 55.

3. Creatine improves mood and cognitive function

Not only has creatine been shown to reduce mental fatigue, which could thereby help you to carry out more frequent/intense workouts, it has also been shown to aid with depressive disorders.

‘One review in 2021 on brain health in women found that women with a major depressive disorder who augmented their daily antidepressant with 5g of creatine responded twice as fast and experienced remission of depression at twice the rate of women who took only their antidepressant,’ Dr Sims tells .

4. Creatine counteracts menopausal muscle, bone and strength loss

For menopausal women, creatine supplementation in combination with resistance training has been shown to counterbalance muscle, bone and strength loss, by ‘reducing inflammation, oxidative stress and bone resorption, while increasing bone formation,’ Dr Sims explains.

‘The research suggests that menopausal women taking high doses of creatine (0.3g per kg a day for at least 7 days) may increase muscle mass and function,’ she adds.

What are the side effects?

The most common misconceptions around creatine are that you’ll gain weight, or experience bloating or gut issues. Newsflash: not true. ‘This stems from the original “bodybuilding” methods of loading creatine and taking 5g, four times per day, with 1g per kg of bodyweight with carbs,’ Dr Sims explains.

‘This combination creates an increase in cellular hydration (i.e. water retention), which can be associated with weight gain and bloating, but taking this amount (over the recommended dosage) is to blame, and the side effects are proven unfounded in women.’

Strength and conditioning coach Andy Vincent agrees that how you take the supplement is what will determine whether or not you get on with it: ‘Creatine doesn’t dissolve in water, which can cause some women to get an upset stomach, but by starting on a low dose, splitting the dose throughout a day or trying buffered forms of creatine, you rule out the risks.

‘Other supposed issues are weight gain and water retention. Weight gain could be aligned with increased muscle tissue, which is one of the best reasons to take creatine, and water retention is intracellular, meaning that it occurs within your cells, and you will not visibly notice it.’

The supposed kidney troubles you may have heard about are also nothing to panic about. ‘This is a common misconception based on the misunderstanding of creatine’s effects on creatinine and its role in kidney damage,’ says Vincent.

‘Creatine is the single most-researched supplement on the planet and no existing studies have reported an effect on kidneys, even when using dosages eight times higher than the recommended.’ Phew.

Can it cause hair loss?

If you’ve heard on the grapevine that creatine could cause hair loss, fret not. It’s BS. Vincent sets the record straight: ‘One study in 2009 documented hair loss due to an increase in the hormone DHT (dihydrotestosterone), which could cause hair loss, but this was a study on men and was only done on men who had a specific gene that made baldness more prevalent. It is not a concern for women and has never been observed in any other research.’

Dr Sims concurs: ‘There is no existing literature to show that hair loss is a side effect of creatine supplementation.’

Does it affect your sleep?

Research has shown that supplementing with creatine monohydrate can slightly increase the number of high-energy phosphates in the brain. This can buffer the accumulation of adenosine and ATP between brain cells during wakefulness, which should reduce sleep hunger (i.e. how much you want to sleep), but may also shorten your sleep duration and reduce the time you spend in deep sleep. This is exactly what a study of rats showed. After the researchers added creatine monohydrate to the animals’ food for four weeks, the rats:

  • Had an increase in the amount of phosphocreatine in the brain regions important to sleep
  • Had less ATP in some brain areas
  • Slept 32% less, which was driven by less deep sleep
  • Had less “rebound” sleep after sleep deprivation

Of course, we are not rats, and something to note is that creatine supplementation probably increases brain creatine more in them (about 30% in rats) than in us as humans (5 to 10%). In turn, creatine supplementation is likely to affect sleep more in rats than it is in us. As it stands, there is no published research into the effect of creatine on human sleep, but going on the above, it makes sense that creatine may reduce sleep duration, albeit reducing your sleep ‘hunger’.

What form of creatine is best?

It’s a resounding recommendation from Dr Sims and Vincent on creatine monohydrate. Both experts tout it for its bioavailability, meaning you’ll absorb more of the nutrients.

Best creatine to shop now

USN Pure Creatine

The micronised form of pure creatine monohydrate supports muscle performance, growth and power.

Tip: Avoid blends and products with a long list of ingredients. The purer the better.

When should you take creatine?

Both Dr Sims and Vincent are keen to clarify that creatine is neither a post nor pre-workout supplement.

‘The aim is to saturate all of your body’s creatine stores, so as long as you take it every day (at any time), you will reap the rewards,’ says Vincent.

How much should you take per day?

3-5g per day. ‘This will vary a little depending on your fitness level and body weight,’ Vincent says. ‘Start on the lower end of the scale if you’re petite and go higher if you’re an advanced trainer. It’s also recommended that vegans and vegetarians start at the higher end of the dosage range to get the most performance benefits.’

‘This is the ideal dosage proven to improve performance, brain health, bioenergetics and gut health, without any risk of bloating or gut issues,’ Dr Sims reassures us.

How often should you take creatine?

Providing your body is A-OK with it, take your creatine supplementation daily. As mentioned, you can split your dosage across each day, if preferable.

Is creatine bad for you?

Providing you stick to the recommended dosages advised by Sims and Vincent above and steer clear of blended products or products with a big list of ingredients, it’s totally safe. Use sites such as or to check whether the creatine supplement you’re considering taking has been tested and cleared for consumption.

One more thing: make sure you don’t overdo it. If you haven’t taken creatine before, try taking just one and giving yourself a few days to see how your body reacts. Then, if all is well, you can continue with your regular supplementation.



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