Every week, clinicians receive renal function results showing a mildly elevated creatinine or an estimated glomerular filtration rate (eGFR) that appears lower than expected.
For many patients, these findings trigger understandable anxiety. A quick internet search often convinces them they have kidney disease. In reality, the explanation may be far more straightforward.
One question is becoming increasingly important: “Are you taking creatine?”
The changing face of creatine supplementation
Creatine was once associated almost exclusively with bodybuilders. Today it has become mainstream.
Older adults use it to support healthy ageing and resistance training. Recreational runners take it to improve recovery. Women approaching menopause are increasingly using it to help maintain muscle strength. Social media has also fuelled interest in its possible cognitive benefits, although evidence for these applications remains less established than for exercise performance.
As use has increased, laboratories are encountering more blood tests where supplementation influences routine renal markers. This is not necessarily a laboratory problem, it is an interpretation challenge.
Understanding creatinine
Serum creatinine is produced through normal muscle metabolism. Healthy kidneys filter creatinine from the bloodstream, making it an important marker when estimating kidney function. However, creatinine is influenced by more than renal filtration.
Levels may increase because of:
- greater muscle mass
- recent strenuous exercise
- dehydration
- high meat intake
- creatine supplementation.
A slightly raised creatinine therefore does not automatically indicate kidney disease. Similarly, an isolated reduction in eGFR should never be interpreted without considering the wider clinical picture.
Why creatine matters
Creatine supplementation increases the body’s creatine stores. A proportion is naturally converted into creatinine. Consequently, serum creatinine may rise modestly despite completely normal kidney function.
For clinicians unaware that supplementation has started, this can create an apparent deterioration in renal function that simply reflects altered physiology rather than kidney damage.
What does the evidence say?
Creatine has been studied extensively for more than two decades. A recent systematic review and meta-analysis of randomised controlled trials concluded that creatine supplementation at recommended doses does not appear to impair kidney function in healthy adults.
That is an important distinction. The evidence should not be interpreted as recommending creatine for everyone. Nor should it be assumed safe for patients with established chronic kidney disease or other significant renal pathology without specialist advice.
Instead, it reminds clinicians that abnormal laboratory results require context.
Questions worth asking
Before acting on a mildly abnormal creatinine result, consider asking:
- Have you recently started taking creatine?
- Have you undertaken intense exercise during the previous 24–48 hours?
- Were you adequately hydrated before the blood test?
- Has your muscle mass changed significantly?
- What did previous renal function tests show?
These questions often provide valuable clinical context.
Practical interpretation
A single mildly abnormal creatinine result should rarely define a diagnosis. Instead, clinicians should consider:
- trends over time
- symptoms
- urine findings
- cardiovascular risk
- medications
- supplement history
- hydration status.
Only by combining pathology with clinical assessment can we distinguish physiological variation from genuine disease.
The role of nutrition professionals
Nutritionists increasingly support patients using creatine responsibly alongside exercise programmes. This creates an opportunity to encourage patients to inform their healthcare team about supplement use before blood testing.
Simple conversations can prevent unnecessary anxiety and repeat investigations.
Supporting better patient care
At Viva Health Laboratories, we believe pathology is most valuable when it informs clinical decision-making rather than creating unnecessary uncertainty. Reliable laboratory results, rapid turnaround and thoughtful interpretation help clinicians provide evidence-based care while avoiding overdiagnosis.
Sometimes the most important result isn’t the creatinine itself. It’s the conversation that follows.
Suggested Blood Profile
For patients where kidney function requires further evaluation:
- Renal Function Profile
- Urine Albumin:Creatinine Ratio
- Full Blood Count
- HbA1c (where indicated)
- Lipid Profile
- Cystatin C (if available and clinically appropriate)
Results should always be interpreted alongside medical history, medication review, supplement use and clinical examination. Drop a line to our support team, support@vivahealthlaboratories.com, to continue the conversation.
About Viva Health Laboratories
Viva Health Laboratories supports healthcare professionals across the UK with rapid turnaround blood pathology, bespoke clinician-designed profiles and dedicated laboratory support, helping clinicians deliver confident, evidence-based patient care.
LINKEDIN POST (Approx. 400 words)
A raised creatinine result doesn’t always mean kidney disease.
As creatine supplementation becomes increasingly popular, many clinicians are seeing mildly raised creatinine results in patients who are otherwise healthy. The immediate concern is often declining kidney function.
But is that always the right conclusion? Creatinine is influenced by much more than renal filtration.
Muscle mass, recent strenuous exercise, hydration and creatine supplementation can all affect serum creatinine concentrations, meaning a single abnormal result should always be interpreted in context.
Recent systematic review evidence also suggests that creatine supplementation, when taken at recommended doses by healthy adults, does not appear to damage kidney function.
For GPs, nutritionists and preventative health clinicians, a few additional questions may make all the difference:
✔ Has the patient recently started creatine?
✔ Have they exercised intensely before the blood test?
✔ Were they adequately hydrated?
✔ What do previous renal results show?
Blood tests should always support clinical decision-making—not replace it.
At Viva Health Laboratories, we believe pathology delivers its greatest value when laboratory data is combined with good history-taking and thoughtful interpretation.
Read our latest blog: Is That Raised Creatinine Really Kidney Disease? We explore how creatine supplementation, lifestyle factors and clinical context can influence renal blood tests, and how to avoid common interpretation pitfalls.
If your practice is reviewing its approach to preventative health testing or renal monitoring, we’d be pleased to discuss how our bespoke blood profiles and rapid turnaround service can support your patients. Drop a line to our support team, support@vivahealthlaboratories.com, to continue the conversation.