Creatine is an extremely popular supplement used to improve exercise performance (1).
It has been studied for 200 years, and is one of the most scientifically valid supplements (2).
In addition to exercise, creatine may also have health benefits (3).
This article explains how creatine improves exercise performance.
Creatine's main role is to enhance energy production in cells.
To understand how it works, you need to understand something about how your cells produce energy.
The most basic form of energy in cells is a molecule called adenosine triphosphate (ATP). This is the "energy currency" your cells use to perform many of their functions.
ATP is a limiting factor in high-intensity exercise, because it runs out quickly when you are working hard.
This brings us back to creatine. About 95% of the body's creatine is stored in your muscles, in the form of a molecule called creatine phosphate (4).
Creatine phosphate can help you replenish the "energy currency" ATP, giving your muscle cells the capacity to produce more energy.
The more creatine you have, the more energy your muscle cells can produce during high-intensity exercise. This leads to enhanced performance (5).
Although creatine's primary benefits are enhanced energy production, it can also increase strength and help you gain muscle (6).
Bottom Line: Creatine helps produce ATP, the cell's most basic form of energy. This increases energy production during high-intensity exercise and leads to improved performance, increased strength and muscle gain.
Research suggests that creatine is one of the most effective supplements available for high-intensity exercise (2).
In fact, several hundred studies have investigated its effects. Over 70% show a positive effect, while the other 30% show a small or insignificant effect. No negative effects have been found (7).
The improvements range from 1–15%, on average. The upper end of this is something that could take months or even years to obtain from training alone (7).
In one study, creatine was shown to significantly reduce the time needed to complete 40 meter sprints (8).
Short-term supplementation also improved elite swimmers' sprint speed to a greater extent than training alone (11).
Bottom Line: Creatine supplements have been shown to enhance high-intensity exercise performance by up to 15%.
This is because ATP energy is crucial for these exercises. They are often short in duration (under 30 seconds) and performed at a very high intensity.
One 6-week training study found that creatine helped add a further 15% weight (11 lbs or 5 kg) to a 1-rep max bicep curl (16).
A weight training study found that creatine increased maximum squat and bench press strength. These results can be seen in the chart below (17):
The same study also reported a 20% increase in testosterone levels for the creatine group, compared to only 5% in the group not taking creatine (17).
Another study tested explosive power and weight lifting strength, finding that creatine helped improve explosive jumps and the amount of repetitions for bench press (19).
Bottom Line: The majority of studies show that creatine can improve strength and power, for both athletes and beginners.
Even though creatine is beneficial for short-duration, high-intensity exercise, research shows that it has less benefit in lower-intensity endurance exercise.
One cycling study compared creatine's effects in both high and low-intensity, finding it only improved high-intensity performance (20).
A large review of the research also found significant improvements for short-duration work, but less of a benefit for endurance exercise (21).
Endurance exercises are low in intensity, and rely less on rapid ATP regeneration. This makes creatine's role less significant, and explains these findings (22).
However, one possible benefit of creatine is its ability to improve your training sessions, which may improve endurance performance in the long term.
In one study, it improved the number of intervals and subsequent amount of training endurance athletes could complete (23).
Therefore, creatine may provide a benefit for endurance athletes who include sprints, high-intensity intervals or strength work in their training.
Bottom Line: The current short-term research suggests that creatine supplements provide little or no direct benefit to endurance performance.
There are several forms of creatine available, some of which are marketed with bold claims that are unsupported by research.
Creatine supplements can increase muscle creatine stores by 10–40%, depending on you and your current levels (7).
If you have low stores, you may see even more noticeable improvements.
A loading protocol is the fastest way to maximize muscle creatine stores. It involves taking a high dose for a few days, and then a lower maintenance dose after that (25).
This usually means 20-25 grams of creatine per day, split in 5-gram doses, for 5-7 days. Then this is followed with a maintenance dose of 3-5 grams per day (2).
Bottom Line: Take 3–5 grams of creatine monohydrate per day, every day. You can maximize your muscle creatine content by "loading" with 20 grams per day for the first 5 days.
Creatine is one of the most scientifically valid supplements on the market.
One form, creatine monohydrate, has been studied the most extensively. It's also the cheapest type available.
A typical dose is 3–5 grams per day, but you can also take 20 grams for 5 days, to rapidly elevate muscle creatine stores.
In high-intensity exercise, creatine can improve performance by up to 15%, and it can also increase strength and help you gain muscle.
Creatine has little to no benefit for lower-intensity endurance exercise, but may be beneficial if you also include high-intensity exercises in your training.
Additionally, creatine is safe for long-term use. No research has shown any long-term issues in healthy individuals.
For more details about creatine, read this: Creatine 101 – What is it and What Does it do?