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We’ve previously covered a wide range of clinical evidence for creatine here. In this article we want to cover a common question, should I cycle creatine?
You may have heard your mate, trainer or read on an Instagram post that you should be cycling your creatine, but why and what are the potential benefits?
What is creatine?
A quick recap: creatine monohydrate is an organic compound found in some meats and fish. Creatine plays an important role in energy production in the body. Adenosine tri-phosphate (ATP) is the energy currency of the human body. When it loses one if its phosphate groups, it gives off energy for us to use. However, this phosphate group needs to be constantly replenished so that we can create more energy. Creatine contains phosphate groups which it donates to produce more energy (1).
A typical creatine supplementation protocol consists of (2,3):
2. Loading phase: 20 grams/ day for 1 week.
3. Maintenance phase: 3-5 grams/ day.
It is well established that a loading phase is not necessary (4) but increases the speed at which an individual reaches the required muscle creatine ‘saturation’ for the performance benefits (5).
However, other protocols have suggested a rest period:
1. Loading phase: 20 grams/ day for 1 week.
2. Maintenance phase: 3-5 grams/ day for 4-6 weeks.
3. Rest phase: 2-4 weeks before beginning another cycle.
The Loading Phase
The loading phase is designed to saturate the muscle with creatine. The average 70kg individual will have ~120g of creatine in their body (1). This can be increased with supplementation but there is only so much the body can hold. This is why there is no point extending the loading phase or consuming 10-20+ grams/ day indefintely. Once your muscles reach saturation, the creatine will stop entering the muscle and instead, degrade in the blood stream within a few hours. You’ll quite literally be peeing your money down the drain.
How would a lifter know they have indeed hit full muscle saturation of this supplement? Without access to complex equipment, daily urine samples and perhaps muscle biopsies, it would be difficult to know, but ultimately it doesn’t really matter.
Users beginning a creatine cycle will find their body weight will initially increase due to creatine’s water retaining properties and plateau off at this level, regardless of the loading phase is continued or dose increased.
This is likely a good enough indication that the trainer is close enough to the highest muscle concentration of creatine they can achieve and there are plenty of other aspects of training for lifters to concern themselves over, apart from worrying about if they have achieved optimal creatine saturation.
The Maintenance Phase
The maintenance phase is simple. It’s designed to replace the creatine you’ve used during exercise or lost through metabolism. The literature is pretty unanimous with 5 grams/ day being sufficient for this role.
It doesn’t tend to matter at what time of day you consume your creatine, as long as it is consistent. Some individuals choose to skip the loading phase. If so, it would be beneficial to increase the maintenance dose to 5-8 grams/ day to aid muscle saturation.
The Time Off Phase?
The time off phase is a contentious subject. It seems that most of the concerns come from:
1. Potential health implications from long term use
2. A ‘tolerance’ to creatine
3. Water retention for competitive sports.
Before we go into detail… No, you don’t need a time off phase.
Potential health implications from long term use
Questions and concerns involving creatine supplementation and kidney damage/renal dysfunction are common. Today, after > 20 years of research which demonstrates no adverse effects from recommended dosages of creatine supplements on kidney health, unfortunately, this concern persists. While the origin is unknown, the connection between creatine supplementation and kidney damage/renal dysfunction could be traced back to two things: a poor understanding of creatine and creatinine metabolism and a case study published in 1998 (6).
In skeletal muscle, creatine is degraded to creatinine, which is exported to the blood and excreted in the urine (7). Healthy kidneys filter creatinine, which would otherwise increase in the blood. Therefore, blood creatinine levels can be used as a proxy marker of kidney function. However, the amount of creatinine in the blood is related to muscle mass (i.e. Males have higher blood creatinine than females) and both dietary creatine and creatinine intake (8). Both blood and urinary creatinine may be increased by ingestion of creatine supplementation and creatine containing foods, such as meat. Creatine is normally not present in urine, but can reach very high levels (>10 g/day) during creatine supplementation (9). There appears to be an unsubstantiated perspective that if the kidneys are “forced” to excrete higher than normal levels of creatine or creatinine, some sort of kidney “overload” will take place, causing kidney damage and/or renal dysfunction.
In reality, transient increases in blood or urinary creatine or creatinine due to creatine supplementation are unlikely to reflect a decrease in kidney function. Additionally, one must exercise caution when using blood creatinine and estimated creatinine clearance/glomerular filtration rate in individuals who consume high meat intake or supplement with creatine. In a review of creatine supplementation studies, Persky and Rawson (10) found no increase in serum creatinine in 12 studies, 8 studies showed an increase that remained within the normal range, and only 2 studies showed an increase above normal limits (although not different from the control group in one study).
In 1998, a case study of a young male with focal segmental glomerulosclerosis and relapsing nephrotic syndrome was reported (6). The young male, who had kidney disease for 8 years and was treated with cyclosporine (i.e., immunosuppressant) for 5 years, had recently begun ingesting creatine supplementation (15 g/day for 7 days; followed by 2 g/day for 7 weeks). Based on increased blood levels of creatinine and subsequent estimate of calculated creatinine clearance, his kidney health was presumed to be deteriorating, although he was otherwise in good health. The patient was encouraged to discontinue creatine supplementation. At this time, it was already known that blood and urine creatinine levels can increase following ingestion of creatine containing food products, including creatine supplements (11). This was ignored by the authors of this case study, as was the inclusion of two investigations which demonstrated that creatine supplementation did not negatively impact renal function (12,13). The dosage of creatine during the maintenance phase, which was also ignored, was only slightly higher than the daily creatine intake of a typical omnivore’s dietary intake, or in terms of food, a large hamburger or steak per day (meat contains about 0.7 g of creatine / 6 oz. Serving). In response to this case study, two separate teams of experts in creatine metabolism wrote letters to the editor of Lancet (12,14). However, the notion that creatine supplementation leads to kidney damage and/or renal dysfunction gained traction and momentum.
Since this case study was reported in 1998, experimental and controlled research trials investigating the effects of creatine supplementation on kidney/renal function has substantially increased (15-17). Overall, in healthy individuals, there appears to be no adverse effects from consuming recommended doses of creatine supplements on kidney/renal function (15-17). Interestingly, Gualano et al. (18) reviewed a small number of case studies which reported renal dysfunction in individuals who were supplementing with creatine. Similar to the case report by Pritchard and Kalra (19), these additional case reports were confounded by medications, pre-existing kidney disease, concomitant supplement ingestion, inappropriate creatine dosages (e.g., 100 X recommended dose), and anabolic androgenic steroid use.
It is prudent to be cautious when ingesting any dietary supplement or medication. Survey data indicates that creatine supplementation usage ranges between 8-74% in athletes and other exercising individuals (reviewed in Rawson et al. (20)). Even with a low estimate of 8% of exercising individuals using creatine supplements, this indicates thousands of exposures across several decades. If the link between creatine supplementation and kidney health was valid, there would be an expected increase in kidney damage / renal dysfunction in low risk (i.e. Young, physically fit, healthy) individuals since 1992 after Harris et al. Published their seminal work (21). After nearly 30 years of post-marketing surveillance, thousands of exposures, and multiple clinical trials, no such evidence exists.
A ‘tolerance’ to creatine
Presumably this theory came about with the popular inclusion of creatine with pre-workouts and the general advise to cycle on and off of stimulant-based pre-workouts. No, you do not build up a tolerance to creatine.
The second theory suggests that if you supplement with creatine for long periods of time, your body will stop producing it naturally. This sounds similar to the physiological reactions of taking anabolic steroids and hormone production. The body naturally produces around 1 gram/ day of creatine. There is no evidence to suggest creatine supplementation effects this.
Water retention for competitive sports.
The last point is the only real reason you would cycle off creatine. There are certain sports such as bodybuilding or combat sports where weight and dryness are important. In this case, creatine supplementation may be stopped to reduce the excess water retention it can bring. However, it’s worth noting that this is side-effect not everyone experiences and should be tailored accordingly.
Take away points.
No, it’s not advised to cycle off creatine unless for specific sporting events.
To this day there is no evidence that creatine consumption is unsafe. Always stick to the recommended doses and enjoy training! However, if you do suffer from pre-existing renal/ kidney disease it would be recommended to consult a medical professional before taking amino acid, or protein-based supplements.
References:
1. Balsom, P.D., Söderlund, K. & Ekblom, B. Creatine in Humans with Special Reference to Creatine Supplementation. Sports Med 18, 268–280 (1994). Https://doi.org/10.2165/00007256-199418040-00005]
2. Buford tw, kreider rb, stout jr, greenwood m, campbell b, spano m, et al. International society of sports nutrition position stand: creatine supplementation and exercise. J int soc sports nutr. 2007;4:6.
3. Hickner rc, dyck dj, sklar j, hatley h, byrd p. Effect of 28 days of creatine ingestion on muscle metabolism and performance of a simulated cycling road race. J int soc sports nutr. 2010;7:26.
4. Willoughby ds, rosene j. Effects of oral creatine and resistance training on myosin heavy chain expression. Med sci sports exerc. 2001;33(10):1674-81.
5. Antonio, J., Candow, D.G., Forbes, S.C. et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?. J Int Soc Sports Nutr 18, 13 (2021). Https://doi.org/10.1186/s12970-021-00412-w
6. Pritchard nr, kalra pa. Renal dysfunction accompanying oral creatine supplements. Lancet. 1998;351:1252–3.
7. Wyss M, Kaddurah-Daouk R. Creatine and creatinine metabolism. Physiol. Rev. 2000;80:1107–213.
8. Hultman, E.; Soderlund, K.; Timmons, J. A.; Cederblad, G.; Greenhaff, P. L. Muscle creatine loading in men. J. Appl. Physiol. (1985) 1996, 81, 232-237.
9. Rawson ES, Clarkson PM, Price TB, Miles MP. Differential response of muscle phosphocreatine to creatine supplementation in young and old subjects. Acta Physiol. Scand. 2002;174:57–65.
10. Persky AM, Rawson ES. Safety of creatine supplementation. Subcell. Biochem. 2007;46:275–89.
11. Hultman, E.; Soderlund, K.; Timmons, J. A.; Cederblad, G.; Greenhaff, P. L. Muscle creatine loading in men. J. Appl. Physiol. (1985) 1996, 81, 232-237.
12. Poortmans JR, Auquier H, Renaut V, Durussel A, Saugy M, Brisson GR. Effect of short-term creatine supplementation on renal responses in men. Eur. J. Appl. Physiol. Occup. Physiol. 1997;76:566–7
13. Greenhaff P. Renal dysfunction accompanying oral creatine supplements. Lancet. 1998;352:233–4
14. Poortmans JR, Francaux M. Renal dysfunction accompanying oral creatine supplements. Lancet. 1998;352:234–3.
15. De Souza E Silva A; Pertille, A.; Reis Barbosa, C. G.; Aparecida de Oliveira Silva, J; de Jesus, D. V.; Ribeiro, A G S V; Baganha, R. J.; de Oliveira, J. J. Effects of Creatine Supplementation on Renal Function: A Systematic Review and Meta-Analysis. J. Ren. Nutr. 2019, 29, 480-489.
16. Gualano B, de Salles Painelli V, Roschel H, Lugaresi R, Dorea E, Artioli GG, Lima FR, da Silva ME, Cunha MR, Seguro AC, Shimizu MH, Otaduy MC, Sapienza MT, da Costa Leite C, Bonfa E, Lancha Junior AH. Creatine supplementation does not impair kidney function in type 2 diabetic patients: a randomized, double-blind, placebo-controlled, clinical trial. Eur. J. Appl. Physiol. 2011;111:749–56.
17. Gualano B, Roschel H, Lancha AH, Brightbill CE, Rawson ES. In sickness and in health: the widespread application of creatine supplementation. Amino Acids. 2012;43:519–29.
18. Gualano B, Roschel H, Lancha AH, Brightbill CE, Rawson ES. In sickness and in health: the widespread application of creatine supplementation. Amino Acids. 2012;43:519–29.
19. Pritchard NR, Kalra PA. Renal dysfunction accompanying oral creatine supplements. Lancet. 1998;351:1252–3.
20. Rawson ES, Clarkson PM, Tarnopolsky MA. Perspectives on Exertional Rhabdomyolysis. Sports Med. 2017;47:33–49.
21. Harris RC, Soderlund K, Hultman E. Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. Clin. Sci. (Lond). 1992;83:367–74.
