DHT and DHT:T ratio without reference to possible ergogenic
mechanisms, but rather focusing on clinical safety. Previous
studies addressing safety issues indicated that creatine
supplementation does not seem to have short-term negative
effects on renal or hepatic function.
comprehensive studies of long-term safety are still required.
The prostate is the best known tissue that is highly responsive
to androgens, including DHT.
DHT may be associated with
benign prostate hypertrophy,
but the association with
prostate cancer remains controversial.
Given this discussion, it would seem that DHT or the
DHT:T ratio may well be possible mechanisms for positive
effects of creatine on muscle mass. The increase in DHT and
DHT:T ratio after 7 days of creatine loading was not seen at
Day 21. There may be a dose–response to the amount of
creatine ingested and the maintenance dose may not be high
enough to maintain the increased ratio. However, in the current
study, we did not see changes in body mass or percent body
fat. Our study recruited rugby players during their competitive
season, after their initial preseason strength orientated training
was completed. On the one hand, this enabled us to determine
the effects of creatine supplementation on already trained
individuals without major additional training changes.
However, this may explain why body composition did not
change. One could speculate that a supplementation period of
longer than 21 days may have altered body composition even
in these subjects whose training did not change appreciably
during the course of the study.
In conclusion, creatine supplementation may act, at least
in part, through the increased rate of conversion of T to DHT.
Because of the potential clinical relevance of the endocrine
results of this study and the high frequency of individuals
using creatine supplementation without monitoring, further
investigation is warranted. Clearly, future studies on the
putative anabolic effects of creatine supplementation should be
more comprehensive in terms of potential humoral and
We thank the rugby players for their cooperation
throughout the duration of the study. We also thank the staff
involved with the rugby players and the Institute for
accommodating the study. Thanks to Mrs. Gail Nell (Chemical
Pathology, Grootte Schuur Hospital), Anneke Le Roux
(Biokineticist, private practice), and Jacolene Kroff, PhD
(Sport Science, Stellenbosch University) for technical support.
1. Bemben MG, Lamont HS. Creatine supplementation and exercise
performance: recent ﬁndings. Sports Med. 2005;35:107–125.
2. Tarnopolsky MA. Clinical use of creatine in neuromuscular and
neurometabolic disorders. Subcell Biochem. 2007;46:183–204.
3. Greenhaff PL, Casey A, Short AH, et al. Inﬂuence of oral creatine
supplementation of muscle torque during repeated bouts of maximal
voluntary exercise in man. Clin Sci. 1993;84:565–571.
4. Balsom PD, Soderlund K, Sjodin B, et al. Skeletal muscle metabolism
during short duration high-intensity exercise: inﬂuence of creatine
supplementation. Acta Physiol Scand. 1995;154:303–310.
5. Vandenberghe K, Van Hecke P, Van Leemputte M, et al. Phosphocreatine
resynthesis is not affected by creatine loading. Med Sci Sports Exerc.
6. Maganaris CN, Maughan RJ. Creatine supplementation enhances
maximum voluntary isometric force and endurance capacity in resistance
trained men. Acta Physiol Scand. 1998;163:279–287.
7. Vandenberghe K, Goris M, Van Hecke P, et al. Long-term creatine intake
is beneﬁcial to muscle performance during resistance training. J Appl
8. Volek JS, Duncan ND, Mazzetti SA, et al. Performance and muscle ﬁber
adaptations to creatine supplementation and heavy resistance training.
Med Sci Sports Exerc. 1999;31:1147–1156.
9. Cancela P, Ohanian C, Cuitino R, et al. Creatine supplementation does not
affect clinical health markers in football players. Br J Sports Med. 2008;
10. Persky AM, Rawson ES. Safety of creatine supplementation. Subcell
11. Shao A, Hathcock JN. Risk assessment for creatine monohydrate. Regul
Toxicol Pharmacol. 2006;45:242–251.
12. Ferrando AA, Tipton KD, Doyle D, et al. Testosterone injection stimulates
net protein synthesis but not tissue amino acid transport. Am J Physiol.
13. Kraemer WJ, Hatﬁeld DL, Spiering BA, et al. Effects of a multi-nutrient
supplement on exercise performance and hormonal responses to
resistance exercise. Eur J Appl Physiol. 2007;101:637–646.
14. Op’t Eijnde B, Hespel P. Short-term creatine supplementation does not
alter the hormonal response to resistance training. Med Sci Sports Exerc.
15. Volek JS, Ratamess NA, Rubin MR, et al. The effects of creatine supple-
mentation on muscular performance and body composition responses to
short-term resistance training overreaching. Eur J Appl Physiol. 2004;91:
16. Bang HJ, Yang YJ, Lho DS, et al. Comparative studies on level of
androgens in hair and plasma with premature male-pattern baldness.
J Dermatol Sci. 2004;34:11–16.
17. Geller J, Sionit L. Castration-like effects on the human prostate of a
5 alpha-reductase inhibitor, ﬁnasteride. J Cell Biochem Suppl. 1992;16H:
18. Castro-Magana M, Angulo M, Fuentes B, et al. Effect of ﬁnasteride on
human testicular steroidogenesis. J Androl. 1996;17:516–521.
19. Zhou ZX, Lane MV, Kemppainen JA, et al. Speciﬁcity of ligand-
dependent androgen receptor stabilization: receptor domain interactions
inﬂuence ligand dissociation and receptor stability. Mol Endocrinol. 1995;
20. Bemben MG, Bemben DA, Loftiss DD, et al. Creatine supplementation
during resistance training in college football athletes. Med Sci Sports
21. Withers RT, Craig NP, Bourdon PC, et al. Relative body fat and
anthropometric prediction of body density of male athletes. Eur J Appl
Physiol Occup Physiol. 1987;56:191–200.
22. Ziegenfuss TN, Lowery LM, Lemon PWR. Acute ﬂuid volume changes in
men during three days of creatine supplementation. J Exerc Physiol
Online. 1998;1(3). http://faculty.css.edu/tboonez/asep/jan13.htm.
23. Safdar A, Yardley NJ, Snow R, et al. Global and targeted gene expression
and protein content in skeletal muscle of young men following short-term
creatine monohydrate supplementation. Physiol Genomics. 2008;32:
24. Snow RJ, McKenna MJ, Selig SE, et al. Effect of creatine supplementation
on sprint exercise performance and muscle metabolism. J Appl Physiol.
25. Ahmun RP, Tong RJ, Grimshaw PN. The effects of acute creatine
supplementation on multiple sprint cycling and running performance in
rugby players. J Strength Cond Res. 2005;19:92–97.
26. Hoffman JR, Ratamess NA, Ross R, et al. Effect of a pre-exercise energy
supplement on the acute hormonal response to resistance exercise.
J Strength Cond Res. 2008;22:874–882.
27. Ratamess NA, Hoffman JR, Ross R, et al. Effects of an amino acid/
creatine energy supplement on the acute hormonal response to resistance
exercise. Int J Sport Nutr Exerc Metab. 2007;17:608–623.
28. Hoffman J, Ratamess N, Kang J, et al. Effect of creatine and
beta-alanine supplementation on performance and endocrine responses
in strength/power athletes. Int J Sport Nutr Exerc Metab. 2006;16:
29. Crowe MJ, O’Connor DM, Lukins JE. The effects of beta-hydroxy-beta-
methylbutyrate (HMB) and HMB/creatine supplementation on indices of
q2009 Lippincott Williams & Wilkins www.cjsportmed.com |403
Clin J Sport Med Volume 19, Number 5, September 2009 Creatine Supplementation and DHT:T Ratio in Male Rugby Players