Short-Term Creatine Use Builds Lean Mass, Appears Safe
WebMD News Archive
March 9, 2000 (Atlanta) -- Canadian researchers say that the popular -- and
controversial -- muscle-building food supplement creatine does not raise blood
pressure or cause kidney problems over the short term. But they also discovered
that when bulk is the goal, it works better for men than for women.
The study, reported in the February issue of Medicine and Science in
Sports and Exercise, set out to measure the effect of creatine on body mass
and to measure side effects in both men and women. Author Mark A. Tarnopolsky,
MD, tells WebMD that while most other studies have focused on strength,
endurance, and body mass issues, this was the first study on creatine to look
at blood pressure and to evaluate gender differences in lean mass.
Sold over the counter in health food stores as a powder, in capsules, and in
other forms, it's thought by many that creatine supplements may cause
dehydration, heat-related illnesses, muscle cramps, minor gastrointestinal
distress, nausea, reduced blood volume, and electrolyte imbalances. Other than
weight gain, negative side effects have not been well documented by
Before the study began, researchers compiled detailed records of the
participants' diet and exercise over the previous four days. They then measured
the body composition of 15 men and 15 women, with an average age of 22, for
body mass and fat using whole body scans called DEXA scans. Next, their blood
pressure was measured and a blood sample was taken. Each subject then performed
six, nine-second-long handgrip exercises for one minute to measure forearm
The creatine was administered in 5 g dosages four times a day for five days
to seven men and eight women; the balance of the subjects were given a placebo.
The creatine was dissolved in juice, milk, or warm tea and taken after meals.
On the sixth day, the creatine and placebos were not given, and all the
subjects again underwent body scans, blood pressure tests, and forearm strength
tests and had blood samples drawn to measure for the presence of creatine.
According to Tarnopolsky, creatine had no effect on blood pressure, kidney
function, or handgrip strength. It did, however, significantly increase the
fat-free mass and total body mass with no changes in body fat for all subjects
-- with much greater changes found in the men than the women.
Were there any surprises? "Yes," says Tarnopolsky, "the fact
that the females didn't increase as much as the males in lean mass."
Tarnopolsky is an associate professor of medicine in neurology/rehabilitation
and kinesiology at McMaster University in Hamilton, Ontario.
He says that the food supplement's effect on kidney function was also an
important part of the study. "There's a lot of misinformation out
there," he says. "Many people feel that somehow creatine will damage