Creatine: why is this supplement being promoted for women's health? Could it help with sleep?

For decades, creatine has been marketed for bodybuilders and gym go-ers as a means to promote muscle growth and enhance exercise performance. Scientists are now exploring whether its benefits extend far beyond muscle, to include brain health, cognitive performance and even resilience to sleep loss.

Creatine

What is creatine?

Creatine is a naturally occurring compound made from three amino acids. Your body produces around one gram each day, mainly in the liver and kidneys, and you can also obtain it from foods such as red meat and fish. Foods high in creatine include beef, pork, salmon, chicken, venison, cod and tuna.

Around 95% of the body's creatine is stored in skeletal muscle, where it acts as a rapid energy reserve during short bursts of intense activity. That's why athletes have used creatine supplements for decades to support strength, power and recovery.

The remaining 5% creatine is found in highly active tissues, including the brain.

Although the brain accounts for only around 2% of body weight, it consumes roughly 20% of our energy at rest. Every thought, memory, conversation and decision relies on a constant supply of cellular energy. Creatine helps to maintain that supply.

What impact does creatine have on the brain?

Every cell in your body is powered by a molecule called ATP (adenosine triphosphate), often described as the body's energy currency.

ATP is used very quickly so our cells therefore need a rapid way to regenerate it whenever demand suddenly increases.

Creatine is stored as phosphocreatine, which acts like a backup battery. When energy demand spikes, phosphocreatine helps to regenerate ATP, allowing cells to keep functioning efficiently.

In muscles, this supports explosive movements. In the brain, it helps maintain the energy needed for thinking, attention, memory and decision-making.

Why could creatine be even more important for women?

Recent evidence suggests that creatine may have particular relevance across a woman's lifespan because of the interaction between hormones, muscle, bone and brain health.

Women appear to synthesise their own creatine at 20% lower rates than men, and consume on average 30-40% less in their diet. One study found that females experienced double the performance benefits following creatine supplementation compared with males.

During the menstrual cycle

Hormonal fluctuations may influence how the body produces and uses creatine, although research is still in its early stages.

Some researchers have suggested creatine requirements may vary across the menstrual cycle, but more studies are needed before firm recommendations can be made.

Pregnancy

The body's energy demands increase substantially during pregnancy. Emerging evidence from animal studies and observational research suggests energy-boosting effects from creatine, but routine supplementation during pregnancy cannot yet be recommended without medical guidance.

Perimenopause and menopause

This is perhaps where creatine becomes particularly interesting.

As oestrogen levels decline, women often experience changes in:

• muscle mass

• bone health

• cognitive function

• energy levels

• sleep quality

While creatine won't address the hormonal causes of these symptoms, it may support muscle strength and preserve lean mass when combined with resistance exercise.

Given that sleep disruption is also common during perimenopause, researchers are increasingly interested in whether creatine could help women remain mentally resilient during periods of fragmented sleep.

What does creatine have to do with sleep?

Sleep isn't simply a period of rest, it's also a time when the brain restores itself.

During waking hours, our brains are constantly working and consuming energy. Sleep allows many of these restorative processes to take place, helping replenish energy stores and prepare the brain for another day.

When sleep is restricted, the brain has to work harder with fewer resources.

Scientists are increasingly interested in whether creatine could provide an additional energy reserve during these periods of increased demand. The focus is becoming on what creatine can do for sleep restriction rather than the impact it has on getting good sleep.

Does creatine improve sleep quality?

One small study in 20 healthy young women who embarked on a 6 week resistance training programme suggested that creatine promoted longer sleep on workout day, in comparison to a placebo, but there were no differences between groups in sleep quality.

Despite some claims online, there isn’t evidence that creatine:

• helps you fall asleep faster

• increases deep sleep

• improves sleep quality

• treats insomnia

In fact, research in rats (which may not be relevant to humans!) actually found that 4 weeks of creatine supplementation reduced sleep duration. The authors proposed that creatine had reduced sleep need, but this remains hard to demonstrate.

There is evidence that creatine supplementation may reduce some of the cognitive consequences of sleep deprivation.

How does creatine affect the sleep-deprived brain?

One recent study investigated what impact a single high dose of creatine would have on healthy young adults who had stayed awake for 21 hours, compared to a placebo. They then measured cognitive performance alongside changes inside the brain.

Participants who received creatine showed:

• faster processing speed

• reduced feelings of fatigue

• improvements in aspects of cognitive performance

• changes in brain energy metabolism

In other words, creatine appeared to help the brain cope better during an acute period of sleep loss.

This was a relatively small study involving just 15 healthy adults, and participants received a single high dose of creatine (0.35g/kg body weight, or >20g) far more than the typical daily maintenance dose of 3-5g. It also looked at one night of total sleep deprivation only.  A follow up study in 29 young adults found similar cognitive benefits from a single dose of 0.20g creatine per kg of body weight. Cognitive performance improved by up to 12%. Interestingly, compared to males, females benefited more in logic, reaction time and processing speed in language and logic tasks.

While the findings are promising, they shouldn't be interpreted as evidence that creatine can replace sleep.

Sleep remains essential for learning, immune function, emotional regulation, metabolic health and countless other processes that no supplement can replicate.

Could creatine protect brain health?

Sleep deprivation isn't the only area attracting attention.

Researchers are also investigating creatine's potential role in:

• healthy ageing

• memory

• attention

• mental fatigue

• recovery following concussion

• neurological disorders

The evidence is mixed.

Some studies report improvements in cognitive performance, particularly during periods of high mental demand or stress, while others find little effect in healthy, well-rested adults.

If your brain already has plenty of energy available, adding more may make little difference. It's during periods of increased demand such as ageing, sleep deprivation or prolonged mental effort, that creatine may have opportunity to help.

Should every woman take creatine?

Creatine is one of the most extensively researched sports supplements available and has an excellent safety profile for healthy individuals when taken at recommended doses. Most of the evidence supports a 3-5g daily dose of creatine monohydrate for exercise capacity and lean body mass. However, as with any supplement, it's sensible to discuss your unique needs with a healthcare professional.

Creatine supplementation may be especially worth considering for women who:

• follow a vegetarian or vegan diet

• regularly perform resistance training

• engage in shift work, or a lifestyle with increased risk of sleep deprivation

• want to support muscle health as they age

• are interested in preserving physical function through midlife and beyond

Whether creatine offers additional benefits for brain health or resilience to poor sleep is an exciting but still developing area of research.