What are the risks and guidelines for using creatinine (creatinine) monohydrate supplements, especially for individuals with impaired renal (kidney) function?

From the Guidelines

Creatine monohydrate supplements should be avoided by individuals with impaired kidney function due to potential risks of worsening their condition. The use of creatine monohydrate supplements can lead to an increase in creatinine levels, which can be problematic for individuals with impaired renal function, as their kidneys may struggle to filter out this excess creatinine 1. For healthy individuals, the generally recommended dosage is 3-5 grams daily, with some protocols suggesting an initial loading phase of 20 grams daily (divided into 4 doses) for 5-7 days followed by a maintenance dose of 3-5 grams daily. However, it is crucial to note that individuals with kidney disease should avoid creatine entirely, as the kidneys are responsible for removing creatinine (a breakdown product of creatine) from the body, and impaired kidneys may struggle with this additional filtration burden, potentially accelerating kidney damage.

Some key points to consider when using creatine monohydrate supplements include:

• Maintaining adequate hydration to help the kidneys process the supplement and reduce strain on renal function
• Regular kidney function monitoring through blood tests, especially for long-term creatine users with risk factors for kidney disease
• Consulting a healthcare provider before using creatine supplements, especially for individuals with a history of kidney problems, high blood pressure, or diabetes
• Being aware of the potential side effects of creatine monohydrate supplements, including water retention, bloating, digestive discomfort, and muscle cramps

It is also important to note that the use of dietary supplements can influence changes in blood pressure, and some supplements, such as licorice and St. John's wort, have been shown to increase blood pressure 1. Additionally, certain supplements, such as horsetail, can have a diuretic effect, leading to hypotension 1. As recommended by the 2012 KDIGO clinical practice guideline for the evaluation and management of CKD, adults with CKD should seek medical or pharmacist advice before using over-the-counter medicines or nutritional protein supplements 1.

From the Research

Risks of Creatinine Monohydrate Supplements

• The use of creatinine monohydrate supplements may pose risks to individuals with impaired renal function, as it may increase the risk of renal dysfunction 2.
• High-dose oral creatine supplementation may stimulate the production of methylamine and formaldehyde, which are potential cytotoxic metabolites of creatine, although there is currently no definite clinical evidence about their adverse effects on kidney function 3.
• Combining creatine supplements with other supplements or taking them at higher than recommended doses for several months may lead to liver and renal complications 4.

Guidelines for Using Creatinine Monohydrate Supplements

• Creatine supplementation appears to be safe for healthy adults when used at recommended loading and maintenance doses, but individuals with a history of renal disease or those taking nephrotoxic medications should exercise caution 2.
• The effective dosing for creatine supplementation includes loading with 0.3 g·kg·d for 5 to 7 days, followed by maintenance dosing at 0.03 g·kg·d, although loading doses are not necessary to increase intramuscular stores of creatine 4.
• Supplementary doses of creatine monohydrate should be of the order of the daily turnover, which is approximately 2 g per day for a 70 kg individual, while therapeutic doses should be taken under medical supervision 5.
• Individuals with impaired renal function or those at risk for kidney dysfunction should avoid using creatine supplements, as they may exacerbate existing kidney problems 3.

Special Considerations

• Creatine supplementation may increase creatinine levels, which can act as a false indicator of renal dysfunction, and therefore, renal function markers other than serum creatinine and creatinine clearance should be used to assess kidney function 2.
• The safety of creatine supplements in children and adolescents has not been established, and long-term use of high doses exceeding 10 gm/day has not been extensively studied 2.
• The quality of creatine monohydrate products is a concern, as they may contain contaminants such as dicyandiamide, dihydrotriazines, creatinine, and ions, which can have adverse effects on health 5.