The Pros and Cons of Creatine

What is Creatine

formulaCreatine is a non-essential amino acid (which means that the body makes it, so it’s not essential to get it in food).

Creatine monohydrate is a dietary food supplement used by athletes, both amateurs and professionals, to improve physical performance.

The typical creatine user is looking for a product that allows him to get results from the exercise he performing: well-cut muscles (aesthetic aspect) as well as increased strength (performance aspect).

Creatine slightly increases strength, volume, mass and muscle definition, (1,3) but seems to have no effect on endurance. A bodybuilder, a boxer, a hockey player or someone who trains for a physical cut can benefit from the use of creatine.

On the other hand, a long-distance runner, a cyclist, a swimmer or a triathlete who especially wants to improve his endurance will not derive much benefit. In fact, they are more likely to experience discomfort (cramps and others) due to dehydration (see side effects below).

Creatine is found naturally in meats (about 5g / kg) and it is synthesized in the liver, pancreas and kidneys at a rate of about 3g per day. The products sold on the market are obtained by synthesis (from sodium sarcosine and cyanamide).

The supplements are sold as powders, tablets, capsules and liquids. You must first know that these forms are not all equivalent (it does not mean that it sells that it is good!): Creatine is not stable in a liquid medium. Moreover, Consumer Lab (2) has not found any liquid product containing the quantity displayed on the label!


Action Mechanism

The mechanism of action of creatine is twofold. On the one hand, it increases intracellular water, which has the effect of swelling the muscles. On the other hand, it serves as a precursor to ATP (intracellular energy), which helps to increase strength and reduce muscle fatigue, especially during so-called anaerobic exercises such as weight training and weightlifting. The increase in muscle mass is therefore due both to the direct effect of creatine and to the effect on ATP which allows the athlete to train more vigorously and for longer. Intensified training alone can explain some of the effects seen with the supplement.

Approved Substance

The International Olympic Committee, like the majority of sports and athletic associations, authorizes the use of creatine. The safety of the supplement could explain this approval, but since it is a natural metabolite, there are no tests to detect the use of the supplement.

Pay attention to imported products such as those from certain Internet sales companies or those sold behind the counter in certain gyms. The purity of these products can be questioned.

Check whether the products you buy are accepted or in the process of being accepted by the NHPD (Natural Health Products Directorate of Health Canada). This assures you of adequate quality control.

Without wanting to appear chauvinistic, the products produced here in Canada are produced under good manufacturing practices which guarantee quality and purity. It is not true everywhere.

Side Effects

Creatine causes very few adverse effects: three potential types are listed. The first is due to its mechanism of action which consists in increasing intracellular water. When you sweat a lot, the risk of dehydration is increased since water is mobilized inside the cell.

Dehydration can lead to disorders such as cramps, sunstroke, muscle fatigue, etc. It is therefore very important to drink lots of water during training.

The second type of side effect is digestive. Several companies suggest on the packaging to take creatine on an empty stomach, but it can cause gastric irritation and nausea.

I have also found no evidence showing that it is better absorbed on an empty stomach.

Personally, I consider that it is better to take creatine with a fruit juice (carbohydrates increase its absorption and its effect) (3-5) and I suggest taking it 1 hour before training. In this way, the peak of blood concentration is obtained at the most useful time: during training. (6)

The third type of side effect comes from the metabolism of creatine. Creatine is the direct precursor of a molecule that serves as a marker for kidney failure: creatinine. Creatine supplements therefore temporarily increase the production of creatinine in the blood and can lead to false alarming results on the creatinine test.

However, when the supplement is stopped, everything is back to normal. You still have to be careful: creatine is not indicated for people with kidney failure whose less functional kidneys have difficulty eliminating this excess creatinine.

An odd adverse effect has been reported to me anecdotally. It seems that some long-term users, when they stop using creatine completely, experience muscle pain for a few days or even weeks after stopping. I have not found scientific validation for this effect, but when creatine has been used to treat certain muscle disorders, similar pain has been reported in rare cases. (7)

Despite the opinion of several alarmist authors, the rate of endogenous synthesis (what is produced by our body) of creatine is not affected in the long term by taking these supplements. (4)


Loading dose vs maintenance dose

The question of the loading dose often comes up. This notion is certainly paying off for those who sell creatine since it encourages consumption of up to 20g per day during the first week.

On the other hand, a loading dose is definitely not necessary, nor even useful in the medium or long term.

After a few weeks of use, there is no noticeable difference in performance or muscle definition between those who took a regular dose of 3 to 5g per day and those who ingested the same dose preceded by a loading dose. . Use when necessary, only on training days, is also as valid (and less expensive) as continuous use.


Creatine can therefore help increase muscle mass by up to 5% compared to exercise alone. It also promotes increased muscle strength, but does not improve endurance.

Those looking for a miracle product to develop muscles without exercise (as if it could be…) will obviously be disappointed.

Without exercise, creatine promotes weight gain, not muscle gain!



References :

    1. Graham AS, Hatton RC.Creatine: A Review of Efficacy and Safety . J Am Pharm Assoc 39 (6): 803-810, 1999.
    2. Review: Muscular Enhancement Supplements: Creatine, HMB, and Glutamine , United States, 2003. (paid site)
    3. Becque MD, Lochmann JD, Melrose DR.Effects of oral creatine supplementation on muscular strength and body composition . Med. Sci. Sports Exerc. , Flight. 32, No. 3, pp. 654–658, 2000.
    4. The American College of Sports Medicine Roundtable on the physiological and health effects of oral creatine supplementation. Med. Sci. Sports Exerc ., Vol. 32, No. 3, pp. 706–717, 2000. (full text available free of charge)
    5. Persky AM, Brazeau GA.Clinical Pharmacology of the Dietary Supplement Creatine Monohydrate . Pharmacol Rev 2001; 53: 161–176. (full text available free of charge)
    6. Deldicque L, Décombaz J, Foncea HZ, et al.Kinetics of creatine ingested as a food ingredient. Eur J Appl Physiol . 2008 Jan; 102 (2): 133-43.
    7. Kley RA, Vorgerd M, Tarnopolsky MA.Creatine for treating muscle disorders . Cochrane Database Syst Rev . 2007 Jan 24; (1): CD004760.