Are There Any Side Effects from Creatine? The only side effect reported in the scientific and medical literature from
creatine supplementation has been weight gain.1,2,71 However, there have been a number of anecdotally reported side
effects reported in the popular literature such as gastrointestinal distress, muscle cramping, dehydration, and increased
risk to musculoskeletal injury (i.e., muscle strains/pulls). Additionally, there has also been concern that short and/or
long-term creatine supplementation may increase renal stress and/or adversely affect the muscles, liver, or other organs
of the body. Over the last few years a number of studies have attempted to assess the medical safety of creatine. These
studies indicate that creatine is not associated with any of these anecdotally reported problems.66,72-80 In fact, there
is recent evidence that creatine may lessen heat stress and reduce the susceptibility to musculoskeletal injuries among
athletes engaged in trainin.66,79,80 While people who take
may experience some of these problems, the incidence of occurrence in
creatine users does not appear to be greater than subjects who take
placebos and in some cases have been reported to be less.73
What is the Best Form of Creatine to Take? Nearly all studies on creatine supplementation have evaluated
pharmacuetical grade creatine monohydrate
in powder form or have used oral or intravenous phosphocreatine
formulations (a more expensive form of creatine). However, since
creatine has become a popular supplement, there are a number of
different forms of creatine that have been marketed (e.g.,
creatine candy/bars, liquid creatine, creatine gum, creatine citrate, effervescent creatine,
etc). Many of these forms of creatine claim to be better than creatine
monohydrate. However, I am aware of no data that indicates that any of
these forms of creatine increases creatine uptake to the muscle better
creatine monohydrate. In fact, a recent study
from my lab indicated that liquid creatine has no effect on muscle
creatine store.81 A few published studies have compared the ergogenic
value of several of these types of supplements to creatine monohydrate.
However, results have generally indicated that although some of these
supplements (i.e., creatine candy, creatine gum, and effervescent
creatine) can improve exercise capacity, they do not appear to work any
better than creatine monohydrate. Consequently, the only potential
benefits that I see from many of these different forms of creatine are
convenience, supplement variety, and/or taste preferences. The greatest
disadvantage, however, is that many of these supplements are more
expensive than creatine monohydrate. There is absolutely no evidence
that you can take less of these types of supplements (e.g., liquid
creatine or effervescent creatine) and get the same benefits as you
would by ingesting higher amounts of creatine monohydrate, due to less
degradation in the stomach, greater intestinal absorption, faster
absorption in the blood, and/or greater muscle uptake. Finally, there
are three primary sources for creatine (Germany, the U.S., and China).
Independent testing has revealed that Chinese sources of creatine may
have less purity and/or contain higher amounts of contaminants like
dicyandiamide, dihydrotriazine, and/or creatinine (converted form of
The best raw sources of creatine monohydrate appear to be from Germany (e.g.,
AlzChem CreaPure®) or the U.S. (e.g., Ferro Pfansteihl). Care should be taken to only purchase high-quality creatine
monohydrate that is produced in inspected facilities that adhere to FDA good manufacturing practice guidelines.
Should I Load or Not? Research has shown that the most rapid way to increase muscle creatine stores is to follow the
loading method described above. Most of the creatine is taken up by muscle during the first 2 to 3 days of the loading
period. While there is one study that suggests that taking lower doses of creatine over time (3 grams/day for 28 days)
increased muscle creatine content,9
it is less clear whether this low-dose protocol enhances exercise
capacity. There are only a few well-controlled studies that reported
creatine supplementation (5-6 grams/day of creatine for 10 weeks) promoted greater gains in strength and muscle mass during training.35,36,82
Should I Take Creatine Alone or With Other Nutrients? There has been considerable interest in finding ways to enhance
muscle uptake of creatine. Many commercially available supplements boast of new improved transport systems that optimize
creatine storage via greater intestinal and/or muscle uptake. Do other nutrients affect muscle concentrations and/or
performance? Before I answer this question, it is important that you know some of the creatine basics. First, research
since the early 1900's has indicated that orally ingested creatine monohydrate is absorbed intact through the intestine
into the blood. The creatine is then either taken up by the muscle or excreted as creatine in the urine. Creatine is
not degraded into creatinine in the stomach and intestinal absorption is not a limiting factor to muscle uptake of
creatine. In fact, one of the ways we determine muscle creatine storage is by subtracting urine creatine output from
oral creatine intake. If a significant amount of creatine was not digested or degraded to creatinine in the stomach
(its only known byproduct), these measurements would be invalid. Second, creatine uptake into the muscle has been
reported to be sodium dependent and mediated by insulin. This means that ingesting creatine with large amounts of
glucose (e.g., 80 - 100 grams) or carbohydrate/protein (e.g., 50 - 80 grams of carbohydrate with 30 - 50 grams of protein),
which is known to increase blood insulin levels, may be an effective way to enhance creatine uptake.81,83-8686
Consequently, I recommend that athletes take creatine with a high
carbohydrate drink (e.g., juice or concentrated carbohydrate solution)
or with a
carbohydrate/protein supplement in order to increase insulin and promote creatine uptake.
A number of
vitamins and minerals,
and/or other potentially ergogenic nutrients (e.g., HMB, sodium
phosphates, bicarbonate, taurine, etc) may provide some added and/or
independent benefits.26,29,34,86-88 For example, our research has shown
greatest increase in muscle mass from creatine supplementation occurred
when creatine was added to a vitamin/mineral fortified
carbohydrate/protein supplement.87,89 It is possible that adding other nutrients like
Arginine Alpha-Ketoglutarate (A-AKG),
ribose, etc may provide additional benefits. Combining creatine with
AAKG and/or other potentially ergogenic nutrients may provide additive
and/or synergistic effects. In fact, as a vasodilator, Arginine AKG is
proving to be a very effective means of transporting creatine and other
nutrients into muscle tissue, yielding quicker and more impactful mass
When is the Best Time to Take Creatine?90-94
The primary mechanism appears to be related to a carbohydrate and
protein stimulated increase in insulin as well as stimulation of
protein synthesis by essential amino acids. Since insulin levels
enhance creatine uptake, it is my view that once an athlete completes
the loading phase,
the best time to take creatine is after exercise with a carbohydrate and/or
Should I Cycle On and Off Creatine? There is no
evidence that cycling on and off creatine is more or less effective
than loading and maintaining creatine. However, the greatest benefits
appear to be to enhance training adaptations. Therefore, if an athlete
wants to cycle creatine, I suggest that they take creatine when they
are involved in heavy training and not take it between training phases.
Does Caffeine or Acidity Affect Creatine?
Athletes often ask whether creatine can be taken with
or whether mixing creatine with acidic drinks will degrade creatine.
There are a couple of studies that indicate that co-ingesting creatine
with large amounts of caffeine may negate some of the
performance-enhancing effects of creatine supplementation.95-98 For this reason, many have warned not to take it with caffeine. However, many of the initial
studies mixed creatine in hot coffee or tea to help dissolve the creatine. Additionally, these studies indicated that
caffeine did not affect muscle uptake of creatine. Consequently, it is my view that this concern is somewhat overstated.
Some have also warned that mixing creatine in acidic solutions (e.g., juices) may degrade creatine to the undesirable
creatinine. Yet, the acid level (pH) of coffee (about 4.5), grape juice (about 3), and orange juice (about 2.8) is less
acidic than gastrointestinal secretions (about 1) and the acid in the stomach (about 1.5). It is well established that
creatine is not degraded through the normal digestive process.99 Moreover, a number of creatine studies instructed the
subjects to mix creatine with juice and reported ergogenic benefit. Therefore, it is unlikely that mixing creatine in
fruit juice would degrade creatine unless you let it sit for several days.
Do Men and Women Respond Differently to Creatine Supplementation?20
In our research, we have found that women typically observe ergogenic benefit following short-term supplementation.
However, gains in body mass and fat free mass are generally not as rapid as men. Nevertheless, women do gain strength
and muscle mass over time during training.
Is the Weight Gain Water or Muscle? As stated above, creatine supplementation typically promotes gains in
body mass and/or fat free mass. Some have suggested that because the gains are fairly rapid, they must be due to fluid
retention. Although it is generally accepted that the initial weight gain may promote some water retention, a number
of recent studies do not support this concept. In this regard, most studies that have evaluated the effects of creatine
supplementation on fluid retention and body composition indicate that although total body water increases, the actual
increase appears to be proportional to the weight gained. In this regard, muscle is about 73% water. Therefore, if
someone gained 10 pounds of muscle, 7.3 pounds of the weight gain would be water and the percentage of total body water
would not be changed. Numerous studies report that long-term creatine increases fat-free mass without an increase in
the percent of total body water. Additionally, several studies have found that these gains were accompanied by increased
muscle fiber diameter (hypertrophy) and gains in strength.31,35,36 Consequently, it appears that the
weight gain associated with long-term creatine supplementation appears to be muscle mass.
Should Children or Teenagers Take Creatine?
may be harmful for children or adolescent athletes. However, it should
be noted that much less is known about the effects of creatine
supplementation in younger individuals. As a result, it is my view that
adolescent athletes should only consider taking creatine if the
following conditions hold true: On the other hand, several
other studies found no effect of low-dose (2 to 3 grams/day), long-term creatine supplementation on exercise capacity.
Consequently, it is my view that the best way to increase creatine stores is to follow the aforementioned creatine loading
technique followed by ingesting 3 to 5 grams/day thereafter to maintain creatine stores. There is
also evidence that coingesting creatine with D-pinitol may augment creatine uptake into muscle.
have also been developed in an attempt to optimize creatine
availability and/or provide other nutrients that may have health,
performance, and/or training benefits. These formulations may also
offer a convenient way to provide key nutrients during training. There
are limited data suggesting that coingesting creatine with
carbohydrate, Research indicates that intense exercise increases anabolic
hormone release. Additionally, ingesting carbohydrate and protein or essential amino acids following intense exercise
may accelerate glycogen resynthesis as well as promote protein synthesis.
About a third of the studies on creatine
have evaluated women and/or mixed cohorts of men and women. Several short-term studies on female athletes have revealed
limited ergogenic value. This led some researchers to question whether women respond to creatine differently than men.
However, a number of recent well-controlled short- and long-term studies in women have reported ergogenic benefits.
No study has indicated that
The athlete is past puberty and is involved in serious/competitive training that may benefit from creatine supplementation;
The athlete is eating a well-balanced, performance-enhancing diet;
The athlete and his/her parents understand the potential benefits and side effects of creatine supplementation;
The athlete's parents approve that their child takes creatine;
The athlete maintains proper hydration;
That creatine supplementation can be supervised by the athlete's parents, trainers, coaches, and/or physician;
That quality supplements are used; and,
The athlete does not exceed recommended dosages.
If these conditions are met, then I do not see a reason why high school athletes should not be able to take creatine.
If these conditions are not met, then I do not believe that creatine supplementation would be appropriate unless prescribed
by their physician. To me, this is no different than teaching young athletes' proper training and dietary strategies to
optimize performance. Creatine is not a panacea or short cut to athletic success. It can, however, offer some benefits to
optimize training of athletes involved in intense exercise in much the same way that ingesting a high-carbohydrate diet,
sports drinks, and/or carbohydrate loading can optimize performance of an endurance athlete.
Is Long-Term Creatine Supplementation Safe?1,73,74,77,78 One cohort of patients has been monitored since 1981 with no significant side
Conversely, research has demonstrated a number of potentially helpful
clinical uses of creatine in heart patients, infants and patients with
creatine synthesis deficiency, patients suffering orthopedic injury,
and patients with various neuromuscular diseases. Consequently, all
available evidence suggests that
creatine supplementation appears to be safe when taken within recommended guidelines.
Is Creatine Supplementation Ethical? Several
athletic governing bodies and special interest groups have questioned
whether it is ethical for athletes to take creatine as a method of
enhancing performance. Their rationale is that since studies indicate
that creatine can improve performance and it would be difficult to
ingest enough food in the diet to creatine load, that it is unethical
to do so. Others argue that if you allow athletes to take creatine,
they may be more predisposed to try other dangerous supplements and/or
drugs. Still others have attempted to lump creatine in with anabolic
steroids and/or banned stimulants and have called for a ban on the use
of creatine among athletes. Finally, fresh off of the ban of dietary
supplements containing 'fat-burning legends of yesterday', some have called for a ban on the sale
of creatine, citing safety concerns.
is not currently banned by any athletic organization although the NCAA
does not allow institutions to provide creatine or other
"muscle building" supplements
to their athletes. Moreover, although some countries limit how much
creatine can be provided per serving in nutritional supplements, I am
not aware of any country that has banned the sale of creatine. The
International Olympic Committee considered these arguments and ruled
that since creatine is readily found in meat and fish, there was no
need to ban creatine. Frankly, I don't see creatine loading any
different than carbohydrate loading. Many athletes ingest high calorie
concentrated carbohydrate drinks in an effort to increase muscle
glycogen stores and/or supplement their diet. If carbohydrate loading
is not a banned practice, then creatine loading should not be banned.
This is particularly true when one considers that creatine
supplementation has been reported to decrease the incidence of
musculoskeletal injuries, heat stress, provide neuroprotective effects,
and/or expedite rehabilitation from injury. It could be argued that not
allowing athletes to take creatine may actually increase the risk of
Athletes have been using creatine as a nutritional supplement
since the mid 1960's. Widespread use as a dietary supplement began in the early 1990's. No side effects directly
attributable to creatine supplementation have been reported in the scientific literature. Nevertheless, there are some
concerns about the long-term side effects of creatine supplementation. Over the last few years, a number of researchers
have begun to report long-term safety data on creatine supplementation. So far, no long-term side effects have been
observed in athletes (up to 5 years), infants with creatine synthesis deficiency (up to 3 years), or in patient populations
(up to 5 years).