Not medical advice. I am a software engineer, not a physician. This page documents my own protocol and the research I read while building it. Talk to a qualified clinician before changing your supplementation, diet or any treatment. Lab reference ranges quoted here vary by laboratory and by individual.
Affiliate disclosure: the iHerb links on this page carry a referral code and pay me a commission if you buy. It does not change your price, and I do not link anything I do not use myself.
The kidneys are a pair of bean-shaped organs, each roughly the size of a fist, that filter approximately 180 liters of blood per day. They remove metabolic waste, excess electrolytes, and toxins while reabsorbing water, glucose, amino acids, and essential minerals. Beyond filtration, the kidneys are endocrine organs: they produce erythropoietin (which stimulates red blood cell production), renin (which regulates blood pressure), and they activate vitamin D into its usable form (calcitriol). Kidney damage is often silent until 60-70% of function is lost, making lab monitoring essential.
Kidney function tests are essential for early detection. By the time symptoms appear, significant irreversible damage has often already occurred.
| Test | What It Detects | Link |
|---|---|---|
| BUN (Blood Urea Nitrogen) | Measures urea levels; elevated in kidney dysfunction, dehydration, or high protein diets | Lab Tests |
| Creatinine (Serum) | Filtered exclusively by kidneys; elevated levels indicate reduced glomerular filtration rate | Lab Tests |
| eGFR (Estimated Glomerular Filtration Rate) | Calculated from creatinine, age, and sex; the gold-standard measure of kidney function (normal >90 mL/min) | Lab Tests |
| Urinalysis | Detects protein (albumin), blood, glucose, and bacteria in urine; proteinuria is an early sign of kidney damage | Lab Tests |
| Calcium (Serum) | Kidneys regulate calcium; abnormal levels may indicate renal dysfunction or secondary hyperparathyroidism | Lab Tests |
Creatine and creatinine: Creatine supplementation (5 g/day) can elevate serum creatinine by 10-20% without indicating actual kidney damage. This is because creatine is non-enzymatically converted to creatinine. If you supplement creatine, inform your doctor so they can interpret eGFR correctly. Cystatin C is an alternative filtration marker unaffected by creatine intake.
Kidney support focuses on reducing oxidative stress, maintaining vitamin D activation, and ensuring adequate hydration rather than heavy supplementation.
| Supplement | How It Helps | Link |
|---|---|---|
| NAC (N-Acetyl Cysteine) | Antioxidant that protects renal tubules from oxidative damage; used clinically to prevent contrast-induced nephropathy. Monitor kidney markers when using long-term. | NAC |
| Vitamin D3 | The kidneys perform the final activation step (1-alpha-hydroxylation). Supplementing D3 ensures adequate substrate; critical as kidney function declines with age. | Vitamin D3 + K2 |
| Omega-3 (EPA/DHA) | Reduces renal inflammation, protects against nephropathy progression, and improves renal blood flow through anti-inflammatory and vasodilatory effects. | Omega-3 |
| Adequate hydration | Chronic mild dehydration forces kidneys to work harder to concentrate urine. Target 2-3 L of water daily; more during exercise or hot weather. Urine should be pale yellow. | — |
Emerging biomarkers outperform creatinine for early CKD detection. A 2025 multi-omics review in Diagnostics established that novel biomarkers — including NGAL (neutrophil gelatinase-associated lipocalin), cystatin C, and beta-2-microglobulin (B2M) — detect kidney damage significantly earlier than serum creatinine alone. Plasma proenkephalin (PENK) has emerged as a particularly accurate marker, showing stronger correlation with measured GFR than creatinine and predicting future renal deterioration in diverse patient populations. Multi-biomarker panels combining 21 markers of kidney damage, fibrosis, inflammation, and cardiovascular disease now provide superior risk stratification for CKD progression.
Updated GFR equations improve accuracy across ages. The 2024 KDIGO guidelines recommend age-adapted GFR equations, addressing longstanding inaccuracies in young adults and the elderly. The European Kidney Function Consortium (EKFC) equation now provides continuous, reliable eGFR estimation across the full lifespan — from pediatric to geriatric patients — offering meaningful improvement over the widely used 2009 CKD-EPI formula.