Long-term creatine use

Geschatte leestijd: 4 minutenIt is not necessary to stop taking creatine to prevent a decrease in endogenous production. Although it seems to be reduced, this effect is of such short duration that there is no period during which there is less creatine (phosphate) in the system than under normal circumstances. Moreover, it appears that the beneficial effects persist even when creatine is used for a longer period.

Creatine use inhibits endogenous production

Last week, I wrote an article about the effect of long-term creatine use on the kidneys. However, most people who inquire about prolonged creatine use do not do so out of fear of kidney problems or nausea. Most are afraid that prolonged intake will inhibit the body’s own production of creatine. Many cycle with creatine for that reason, for example, using it for six weeks and then not using it for four weeks. When using anabolic steroids, it can take months to sometimes even longer than a year for the body to start producing testosterone again, depending on the duration and extent of use and the type of anabolic. If not handled properly, all the gains made during the cycle will disappear as if they never existed.

Although in theory, there does seem to be inhibited endogenous production of creatine, in practice, this is of such short duration that it is not a reason to temporarily stop taking creatine.

Practice: After cessation of intake, breakdown of creatinine is the same as before supplementation

However, the question is how long this effect lasts after cessation of intake and what effect it has during intake. You take creatine to replenish your own supply. The questions you need to ask yourself are therefore:

1. Whether with the supplementation plus the potentially decreased own production, you still have a greater supply than without intake.
2. How long the decreased own production lasts when you stop taking creatine.

English researchers looked at the decrease in the breakdown product creatinine of creatine users and a group that received a placebo. More creatine means more breakdown, so more creatinine. Therefore, when you use creatine, you would expect more creatinine to appear in your urine, and that is indeed the case. When you stop taking creatine, two things can happen:

1. The creatinine level in urine returns to the starting point. This would mean that the own production has already started again and there is as much creatine as at the beginning.
2. The creatinine level in urine drops below the starting point. This would mean that the own production is still reduced. Because nothing comes from outside anymore, there would therefore be less creatine than at the beginning.

The English researchers observed the first scenario (fig. right). The creatinine level quickly returned to the original level, but not below it. In this respect, there is no reason to stop taking creatine. The own production is restarted so quickly that there is no period during which there is both nothing from outside and not yet produced by the body. What I don’t understand is why creatinine decreased in the placebo group.

Practice: Long-term use still results in increased lean body mass

Perhaps even more interesting are the results of long-term creatine use. However, far less research has been done on this than on the results.

Positive results from creatine for 20 weeks: more lean mass and strength

Belgian researchers gave young women 20 grams of creatine for 4 days [4]. Then, they received 5 grams per day for 10 weeks. Another group received a placebo. During the 10-week period, the ladies trained for an hour three times a week. The amount of creatine was measured, but also strength (leg press, bench press, leg curl, leg extension, squat, shoulder press, and sit-ups) and these were compared with the placebo group. After the ten weeks, training was stopped. A small group then continued with the study for another 10 weeks, still taking 5 grams of creatine per day but no longer exercising (“detraining period”).

During the ten weeks of training, the concentration of creatine phosphate in the creatine group increased by 6%. Maximum strength increased by 20-25% more than in the placebo group, and lean mass increased by 60% more (partly water). Even in the group that continued for another ten weeks without training but maintained the daily intake of 5 grams, these levels remained elevated. After stopping after 10 weeks and discontinuing creatine intake, the concentration of creatine phosphate returned to “normal” within four weeks, but not below.

So after twenty weeks, there was no decrease in the amount of creatine phosphate, but there were still improved results.

Is creatine not effective for everyone?

Within the test groups in studies, differences in effects on the various participants are always observed. Some people respond very well to creatine while others do not at all. This is a subject for a subsequent article, but it had to be mentioned here to somewhat qualify the positive effects of creatine as stated above.

Conclusion

Although endogenous production of creatine seems to be reduced during use, this does not lead to a period during which there is less creatine (phosphate) in the system than usual. Therefore, this is not a reason to temporarily stop taking creatine.

References

1. Guthmiller P, Van Pilsum JF, Boen JR, McGuire DM. Cloning and sequencing of rat kidney L-arginine:glycine amidinotransferase. Studies on the mechanism of regulation by growth hormone and creatine. J Biol Chem. 1994 Jul 1;269(26):17556-60. PubMed PMID: 8021264.
2. McGuire DM, Gross MD, Van Pilsum JF, Towle HC. Repression of rat kidney L-arginine:glycine amidinotransferase synthesis by creatine at a pretranslational level. J Biol Chem. 1984 Oct 10;259(19):12034-8. PubMed PMID: 6384218.
3. Hultman E, Söderlund K, Timmons JA, Cederblad G, Greenhaff PL. Muscle creatine loading in men. J Appl Physiol (1985). 1996 Jul;81(1):232-7. PubMed PMID: 8828669.
4. Vandenberghe K, Goris M, Van Hecke P, Van Leemputte M, Vangerven L, Hespel P. Long-term creatine intake is beneficial to muscle performance during resistance training. J Appl Physiol (1985). 1997 Dec;83(6):2055-63. PubMed PMID: 9390981.