Effect of oral creatine supplementation on urinary methylamine, formaldehyde, and formate.
OBJECTIVE
It has been claimed that oral creatine supplementation might have potential cytotoxic effects on healthy consumers by increasing the production of methylamine and formaldehyde. Despite this allegation, there has been no scientific evidence obtained in humans to sustain or disprove such a detrimental effect of this widely used ergogenic substance.


METHODS
Twenty young healthy men ingested 21 g of creatine monohydrate daily for 14 consecutive days. Venous blood samples and 24-h urine were collected before and after the 14th day of supplementation. Creatine and creatinine were analyzed in plasma and urine, and methylamine, formaldehyde, and formate were determined in 24-h urine samples.


RESULTS
Oral creatine supplementation increased plasma creatine content 7.2-fold (P < 0.001) and urine output 141-fold (P < 0.001) with no effect on creatinine levels. Twenty-four-hour urine excretion of methylamine and formaldehyde increased, respectively, 9.2-fold (P = 0.001) and 4.5-fold (P = 0.002) after creatine feeding, with no increase in urinary albumin output (9.78 +/- 1.93 mg x 24 h(-1) before, 6.97 +/- 1.15 mg x 24 h(-1) creatine feeding).


CONCLUSIONS
This investigation shows that short-term, high-dose oral creatine supplementation enhances the excretion of potential cytotoxic compounds, but does not have any detrimental effects on kidney permeability. This provides indirect evidence of the absence of microangiopathy in renal glomeruli.
Poortmans
Jacques R
JR
Higher Institute of Physical Education and Physical Therapy, Free University of Brussels, Brussels, Belgium. jrpoortm@ulb.ac.be
Kumps
Alain
A
Duez
Pierre
P
Fofonka
Aline
A
Carpentier
Alain
A
Francaux
Marc
M
D000284:Administration, Oral; D000328:Adult; D003401:Creatine / Q000008:administration & dosage / Q000494:pharmacology*; D003404:Creatinine / Q000097:blood / Q000652:urine; D019587:Dietary Supplements; D005557:Formaldehyde / Q000652:urine*; D005561:Formates / Q000652:urine*; D006801:Humans; D008297:Male; D008744:Methylamines / Q000652:urine*
D005561:Formates; D008744:Methylamines; C030544:formic acid; D005557:Formaldehyde; D003404:Creatinine; C027451:methylamine; D003401:Creatine