Question: Is Creatine Safe?
by Bill Calberry
I am a woman runner. Can you tell me the effects of Creatine on a woman's body? I do not know much about it. Will it improve my running performance? If you can help me on this, I would really appreciate a response.
OK, there's been a lot of misunderstanding about this stuff lately so let's get into it; but before we do, we need to start with a quick bit of biochemistry. I promise it won't hurt.
All chemical reactions that occur within living cells, including those that occur in striated muscle cells, and that result in the production of mechanical force, require an input of energy. The source of that energy, and indeed the source of energy for all biological processes, is a compound called Adenosine-Triphosphate (ATP). Though your system does extract energy from a wide range of chemically different source materials (food), and can store it in various intermediary forms to meet both immediate and future energy requirements, including but not limited to circulating glucose, stored glycogen, proteins, fats, alcohols and ketones; these compounds must all eventually be broken down, transported to where they are needed, and converted to ATP at or near the site where a reaction is to occur before the energy within them can actually be released and utilized to perform work (power chemical reactions).
ATP is a relatively simple compound consisting of a sugar (Ribose) molecule, an Adenine base, and three molecules of Inorganic-Phosphate bonded to the end. Without getting into a lot of detail, energy stored in an ATP molecule is released and made available to power biological reactions when the chemical bond between the end Phosphate and the rest of the molecule is severed in the presence of water. The byproducts of this reaction are ADP (Adenosine-Diphosphate), and the severed Pi (Inorganic-Phosphate), which can later be recombined to form another ATP molecule that can again be split to power further reactions.
With regard to ATP as it is used to power muscular contractions, although your body does store some pure (free) ATP in the muscles for immediate use, those stores are very small compared to the rate at which the muscles are capable of consuming it when called upon to produce near maximal forces (as in Strength Training activities, or explosive movements like sprinting). In fact the local supply of ATP in a muscle cell can be exhausted in little more than a second when force output is maximal. Once the available ATP is gone it must be replaced from some other source, otherwise no further muscular activity will be possible. Muscles are completely incapable of either shortening or lengthening to create skeletal movement without ATP.
Although your body has various metabolic pathways (chains of sequential chemical reactions) by which it can provide ATP to supply working muscles, only one can produce enough at a sufficient rate to maintain maximal levels of performance when free ATP has been consumed, that is the Phosphocreatine pathway. Essentially this is a very simple pathway for rapidly recombining ADP with Pi to produce very large amounts of ATP in a short period of time. The process involves the use of an enzyme called Creatine Kinase to catalyze a reaction in which Phosphocreatine (Creatine + Pi) stored in the muscles "donates" its Phosphate to the ADP molecule left over when a molecule of free ATP is split to release energy. This results in one new molecule of ATP and one of Creatine. Depending on the amount of Phosphocreatine stored in the muscle, this pathway can typically operate at optimal yield for 10-15 seconds, at which point PCr stores will then become depleted and the muscles must rely on the remaining pathways (Glycolytic and Aerobic) for the bulk of their ATP supply from then on. Unfortunately however, because neither of these pathways is capable of producing ATP at anywhere near the rate of the PCr pathway, peak muscular tension declines markedly once the PCr pathway becomes depleted (which is the reason that athletes cannot maintain true maximum performance for longer than 10-15 seconds; it is biochemically impossible).
Creatine (methyl guanidine-acetic-acid) is a naturally occurring substance that is present in various foods, and is also produced in the body by combining the three Amino Acids Arginine, Glycine, and Methionine. Therefore it is not a drug or a foreign substance as many erroneously believe, but a simple nutrient your body both derives from food and manufactures itself. Frequent and intense muscular activity however, can deplete Creatine stores beyond the ability of the body to produce, or to acquire enough from the diet, to maintain optimal levels in the muscles.
The Creatine supplements you can purchase are therefore intended to help make up the difference and ensure that there is an ample supply on hand to combine with Pi and make certain that Phosphocreatine stores within the muscle are restored to optimal levels after Exercise. Therefore it can aid athletes that depend heavily on the Phosphocreatine pathway to generate quick bursts of energy during training or competition. There is no conclusive research I am aware of however, that shows a differential effect between men and women; although various companies do market products purported to be gender specific in order to increase sales.
As a runner, you may benefit from Creatine supplementation if you engage in sprinting events. If you are a middle or long distance runner however, you do not require bursts of maximal performance and I doubt you'll notice an effect from using this supplement. You'd be better to focus on making sure you take in plenty of carbohydrates (a mix of simple and complex) with a bit of protein after your training sessions to replenish Glycogen stores in your muscles (a more long term and complex energy source that is also stored within the muscles to fuel contractile activity) and aid recovery.
WOW!!! Thank you so much for taking the time to type all of that! Being a PT major and taking a semester of biochemistry definitely came in handy there! Anyway, I was just wondering if it would have any visible adverse effects, like acne, accelerated body hair growth, B.O. (or something scary like that). From what I gather, the answer to that question is no, but if I am wrong, would you please let me know? Oh yeah... I am a Heptathlete, and I compete in everything from the 800m down (including pole vault). So I'm guessing Creatine may help me, but will it only help me once for 15 seconds?
You're welcome. You are correct with regard to possible side-effects. About the only problem that does seem to occur in some people (and I'm talking about effects that can be clinically documented and directly linked to Creatine supplementation, not anecdotal accounts, hearsay, or gym chatter) is the occasional upset stomach and/or mild water retention, particularly when using Creatine on it's own, dissolved simply in water. Although much of this often seems to be linked to substandard or "bargain" products and many find the problem goes away when they switch to a better quality brand.
I want to clarify that the Phosphocreatine pathway is not a one shot deal; like some kind of rocket booster you fire once, and then it's discharged. Remember that when Phosphocreatine (PCr) donates its Phosphate (Pi) to an ADP molecule to form a new ATP molecule, this leaves a molecule of Creatine free to be rejoined to the Pi that will be released when ATP is subsequently split to produce energy. However the recombination process to replenish PCr stores does proceed at a much slower rate than the muscles can use up existing PCr when operating at or near full capacity. In fact it can take many hours to fully replenish muscles stores. So although a short recovery period of even a minute or two will result in at least partially restored levels of PCr, allowing the pathway to continue to function, it will only do so at reduced capacity. That is why a few minutes after a full out sprint you are able to run the same distance again, but not quite able to achieve the same top speed. Making sure that you are not Creatine deficient however, is obviously going to be helpful in ensuring that your PCr stores are replenished as quickly as possible though.
Given that you do in fact compete in events requiring short bursts of maximum muscular activity, you may find this supplement helpful in aiding your recovery from training and competition (by replenishing PCr in your muscles). Just don't expect miracles, and don't think of Creatine as a performance enhancer, any more than you would Carbohydrate or a good Vitamin/Mineral supplement. All of these are nothing more than nutrients, essential for ensuring optimal function.