Two years non-stop creatine without side effects

It’s safe to take continuous not-too-high doses of creatine. Neurologists at the University of Munich conclude this from the longest-running, most comprehensive piece of research on the safety of creatine in humans published so far. The researchers gave their sixty-year-old test subjects – all suffering from Parkinson’s – four grams of creatine monohydrate for a period of two years.

Neurologists hope that creatine supplements can help protect people against neurological diseases like Parkinson’s. They had already discovered that mice live longer if creatine is added daily to their food. The supplement delays ageing processes that appear to be accelerated in the brains of Parkinson’s sufferers.


The main fear with creatine is that it causes kidney damage. The fear is theoretical, however. Creatine is converted into creatinine, and a high creatinine level is a marker for kidney damage. No research has been done on whether this is also a good marker if you take creatine, but that hasn’t stopped doctors from scaring the hell out of creatine users. Brazilian researchers, who were using cystatin C rather than creatinine as a marker, reported that creatine supplements improved kidney function.

Doctors don’t actually encounter kidney damage very often in creatine users. The researchers in Germany found two cases in the literature, and one of these is questionable. If creatine users develop problems, they are nearly always also using other substances, such as dianabol. [Orv Hetil. 2003 Dec 7;144(49):2425-7.]

The longest study on creatine side effects lasted eighteen weeks. The oldest test subjects were in their forties. What’s more, the studies didn’t look at that many variables. That’s why the German neurologists are sounding their own trumpet.

They started by giving their test subjects a daily twenty grams of creatine for a week. Then they reduced the dose to two grams per day for a period of six months. For the remaining eighteen months the subjects were given four grams of creatine per day. This regime was intended to increase the amount of creatine in the brain by ten percent, and so offer protection to the brain cells.

The graph below shows what happened to the level of creatine over the two-year period. The control group – represented by black squares – had less creatinine in their blood than the creatine group – represented by the triangles. As time progresses, however, it seems that creatine users’ bodies learn how to eliminate creatinine more efficiently from the blood.


The other marker for kidney damage, cystatin C, shows a different picture. From the start of the trial, the creatine users have less cystatin C in their blood than the control group.


The researchers also did more blood analyses to look for other kidney damage markers. The results are shown below. There was no significant difference between the creatine group and the control group.


If sixty-year-old Parkinson’s sufferers can take creatine safely for two years, then super-healthy power athletes don’t have to worry about the risks of creatine supplements. That doesn’t mean to say though that continuous use is therefore useful. Going by unpublished research done by the nutritionist Luc van Loon [Google] in Maastricht, Netherlands, you’d have to conclude that it isn’t. His research shows that muscle cells are only capable of retaining higher levels of creatine for two months, and no longer. If you continue taking the supplement, the creatine concentration starts to go down: probably the cells stop manufacturing creatine.

Long-term creatine supplementation is safe in aged patients with Parkinson disease.


The food supplement creatine (Cr) is widely used by athletes as a natural ergogenic compound. It has also been increasingly tested in neurodegenerative diseases as a potential neuroprotective agent. Weight gain is the most common side effect of Cr, but sporadic reports about the impairment of renal function cause the most concerns with regard to its long-term use. Data from randomized controlled trials on renal function in Cr-supplemented patients are scarce and apply mainly to healthy young athletes. We systematically evaluated potential side effects of Cr with a special focus on renal function in aged patients with Parkinson disease as well as its current use in clinical medical research. Sixty patients with Parkinson disease received either oral Cr (n = 40) or placebo (n = 20) with a dose of 4 g/d for a period of 2 years. Possible side effects as indicated by a broad range of laboratory blood and urine tests were evaluated during 6 follow-up study visits. Overall, Cr was well tolerated. Main side effects were gastrointestinal complaints. Although serum creatinine levels increased in Cr patients because of the degradation of Cr, all other markers of tubular or glomerular renal function, especially cystatin C, remained normal, indicating unaltered kidney function. The data in this trial provide a thorough analysis and give a detailed overview about the safety profile of Cr in older age patients.

PMID: 19083405 [PubMed – indexed for MEDLINE]