What the value means
C-reactive protein (CRP) is made by the liver in response to inflammation. Laboratories often set the upper limit around 5 mg/L, because standard CRP is mainly used to detect infection. Low-grade, so-called silent inflammation is assessed with a more sensitive test (hsCRP): values below 1 mg/L are considered low risk, 1–3 mg/L average and above 3 mg/L higher cardiovascular risk. A result within the reference range is therefore not necessarily optimal. CRP is not specific, though – it does not tell you where the inflammation comes from, and a single reading can be affected by something minor.
Possible causes
- Abdominal fat and insulin resistance – fat tissue around the belly releases inflammatory substances.
- Smoking – one of the most common reasons for persistently higher CRP.
- Recent infection, vaccination or injury – even a cold two weeks ago can still raise the value.
- Intense exercise – a hard session a few days before the test raises CRP temporarily.
- Short sleep and chronic stress – both are associated with higher inflammatory markers.
- Gum disease and other hidden inflammation – such as periodontitis, autoimmune or bowel conditions.
- Oral hormonal contraception or oral hormone therapy – can raise CRP; decisions about treatment belong with your doctor.
What you can do
- Repeat the test – in 2–3 weeks, when you are well and have had a few days without hard training; ideally as hsCRP.
- Mediterranean-style eating – vegetables, legumes, fish, olive oil, nuts; fewer ultra-processed foods.
- Regular physical activity – lowers inflammatory markers over time, especially together with losing abdominal fat.
- Sleep and not smoking – 7–9 hours of sleep and quitting smoking are among the most effective steps.
- A dental check-up – gum inflammation is common and easily overlooked.
When to see a doctor
Discuss the result with your doctor if CRP stays raised on repeat testing or if you have other risk factors such as high LDL, high blood pressure or diabetes. See a doctor sooner if CRP is above 10 mg/L, or if you have fever, night sweats, unexplained weight loss, painful or swollen joints, or long-lasting digestive problems.