Table 1.

Effects of creatine supplementation on markers of exercise-induced muscle-damage

Supplementation protocol and study design	Exercise stress	Biological outcomes	Functional outcomes	Perceived outcomes	Overall effect of creatine on muscle-damage	References
20 g/day for 5 days; DB, PC	Unstressed	No increase in resting CK	NA	NA	No effect	[134]
20 g/day for 1 day, 20 g/day for 5 days, followed by 3 g/day for 8 wks with training; DB, PC	Unstressed and supervised resistance exercise 3 × week	No increase in resting CK	NA	No reports of cramping or muscle injury	No effect	[133]
Mean loading dose 13.7 g/day, mean maintenance dose 9.7 g/day, duration 0.8–4 years; RET	Maintained training; subjects were elite athletes	ND in LDH	NA	No reports of muscle tears, greater number of reported muscle cramps in control group	No effect	[135]
20 g/day for 5 days; DB, PC	50 maximal eccentric contractions of elbow flexors	ND in post-exercise CK, LDH between groups	ND in post-exercise strength, ROM between groups	ND in DOMS between groups	No effect	[46]
15.75 g/day for 5 days followed by 5 g/day for 21 mo; OL	Maintained training; subjects were division IA college football players	ND in CK and LDH between groups	NA	NA	No effect	[136]
20 g/day for 5 days; DB, PC	30-km running race	Reduced post-exercise CK, LDH, PGE2, TNF-α in creatine group	NA	NA	Beneficial effect	[114]
0.3 g/kg/day for 5 days followed by 0.03 g/kg/day for 5 days; DB, PC	5 sets of 15–20 squats with 50% 1-RM	ND in post-exercise CK, LDH between groups	ND in post-exercise strength, ROM between groups	ND in post-exercise DOMS between groups	No effect	[140]
20 g/day for 5 days; DB, PC	Half-distance Ironman triathlon	Reduced post-exercise TNF-α, IFN-α, IL1-β and PGE2 in creatine group, ND in IL-6 between groups	NA	NA	No effect	[110]
0.3 g/kg/day for 5 days followed by 0.1 g/kg/day for 14 days; DB, PC	4 sets of 10 eccentric only leg press, leg extension, and leg curl with 120% concentric 1-RM	Reduced post-exercise CK and LDH (trend p = 0.09) in creatine group	Increased recovery of isometric and isokinetic knee extensor strength	NA	Beneficial effect	[112]
0.6 g/kg/day for 5 days; DB, PC	3 sets of 10 of bench press, seated row, leg extension, leg curl, and leg press with 75% of 1-RM	ND in post-exercise CK between groups	NA	NA	No effect	[139]
20 g/day for 7 days followed by 6 g/day for 29 days; DB, PC	7 sets of 10 eccentric leg extension at 150% concentric 1-RM (opposite leg tested at day 30)	ND in post-exercise CK or LDH	ND in post-exercise ROM, dynamic strength, or isometric force at 8 days; increased isometric force at 30 days	ND in post-exercise DOMS	Beneficial effect	[138]
20 g/day for 5 days; DB, PC	Ironman triathlon	Reduced post-exercise CK, LDH, ALD, GOT, GPT, ND in CRP between groups	NA	NA	Beneficial effect	[111]
40 g/day for 5 days followed by 10 g/day for 5 days; DB, PC	6 sets of 10 eccentric contractions at 75°, 90°, and 120° per sec	NA	ND in post-exercise muscle force production	ND in post-exercise DOMS	No effect	[137]
20 g/day for 5 days; DB, PC	Repeated bouts of 4 (14 days apart) sets of biceps curls with 75% of 1-RM to concentric failure	Reduced post-exercise CK in creatine group after second bout	No decrease in post-exercise ROM in creatine group after second bout	Reduced post-exercise DOMS in creatine group after second bout	Beneficial effect	[115]
0.3 g/kg/day for 7 days; DB, PC	Six 35-m maximal sprints with 10-sec rest between bouts	Reduced post-exercise TNF-α, CRP, LDH in creatine group. No effect on oxidative stress markers	NA	NA	Beneficial effect	[113]

1-RM 1 repetition maximum, ALD aldolase, CK creatine kinase, CRP c-reactive protein, d day, DB double blind, DOMS delayed onset muscle soreness, GOT glutamic oxaloacetic acid transaminase, GPT glutamic pyruvic acid transaminase, IFN interferon, IL interleukin, LDH lactate dehydrogenase, mo month, NA not assessed, ND no difference, OL open label, PC placebo controlled, PGE ₂ prostaglandin E₂, RET retrospective, ROM range of motion, sec second, TNF tumor necrosis, wk week