You may not think of your fingernails as a health diagnostic tool—but they’re more informative than you realize. In fact, your nails can offer early clues that something deeper is going on in your body, especially when it comes to kidney function.

If you've noticed changes in your nails—such as unusual ridges, color shifts, or brittleness—it could be more than just cosmetic. These changes may reflect how well your kidneys are working.

This guide will help you understand:

• How nail health connects to kidney function
  

• What nail changes may suggest kidney disease
  

• Why these symptoms occur
  

• How they differ by stage of kidney disease
  

• What you can do to support your nails—and your kidneys

How Are Nails and Kidneys Connected?

Your kidneys filter toxins, balance fluids and electrolytes, and regulate hormones that affect blood, bones, and even skin and nails. When they stop working properly—as in chronic kidney disease (CKD)—those functions break down. This can affect the health of tissues that grow quickly, including your fingernails and toenails.

Reasons for nail changes in kidney disease include:

• Toxin buildup: Waste products not being filtered properly can affect nail beds.
  

• Nutritional imbalances: CKD affects absorption of protein, zinc, iron, and vitamins.
  

• Anemia: Poor kidney function reduces erythropoietin, a hormone that supports red blood cells.
  

• Fluid retention or malnutrition: These affect blood flow and oxygenation to extremities.
  

• Dialysis-related changes: The process of filtering blood externally also alters biochemistry.
  

Nail Changes Commonly Seen in Kidney Disease

1. Half-and-Half Nails (Lindsay’s Nails)

What it looks like: The lower half of the nail (closer to the cuticle) is white, while the upper half is darker—reddish, brown, or pink.

What it might mean: Seen in up to 50% of people with chronic kidney disease. The cause is thought to be vascular changes and melanin deposition due to uremia (toxin buildup). 

This visual cue is often associated with uremia and may coincide with biochemical changes like high urobilinogen in urine, reflecting deeper systemic toxicity.

2. Terry’s Nails

What it looks like: Most of the nail appears pale or white, with a narrow strip of normal pink at the tip.

What it might mean: Though more associated with liver disease, Terry’s nails can appear in CKD, heart failure, or diabetes. It’s a sign of decreased blood flow to the nail bed.

3. Beau’s Lines

What it looks like: Horizontal indentations or grooves across the nails.

What it might mean: These lines reflect a pause in nail growth, often caused by major illness or metabolic stress—such as an episode of acute kidney failure or infection.

4. Spoon Nails (Koilonychia)

What it looks like: Nails are thin and dip inward, forming a spoon-like shape.

What it might mean: Often tied to iron-deficiency anemia, which is common in advanced CKD. Spoon nails may signal poor red blood cell production and poor oxygen delivery.

5. Muehrcke’s Lines

What it looks like: Pairs of white, horizontal lines that run parallel to the lunula (the crescent-shaped base of the nail).

What it might mean: Often associated with low serum albumin levels, which occurs in nephrotic syndrome, proteinuria, or liver issues.   

6. Leukonychia (White Nails)

What it looks like: Full or partial whitening of the nail bed.

What it might mean: White nails can result from low albumin, common in protein-losing kidney conditions or severe malnutrition in CKD.

7. Splinter Hemorrhages

What it looks like: Thin, red or brown vertical lines under the nails.

What it might mean: These lines may occur with vasculitis, endocarditis, or inflammation—conditions occasionally seen in late-stage kidney disease or dialysis patients.

Stages of Kidney Disease and Nail Symptoms

Nail changes may evolve as kidney disease progresses through its stages:

Note: Not all people with CKD will show nail changes, and nail conditions alone are not diagnostic. They are supportive clues.

Differentiating Kidney-Related Nail Changes from Other Causes

Not all nail abnormalities are kidney-related. Other potential causes include:

• Thyroid disease (especially brittle nails or thinning)
  

• Vitamin B12 deficiency (darkened nails or ridges)
  

• Liver disease (Terry’s nails or yellowing)
  

• Psoriasis or fungal infection (pitting, discoloration, thickening)
  

• Chemotherapy or radiation exposure (Beau’s lines)
  

That’s why it’s important to consider the full picture—other symptoms, lab results, and medical history—before drawing conclusions.

To understand whether kidney function may be a factor, consider looking into a urine protein/creatinine ratio, which helps identify abnormal protein loss through urine.

What Should You Do If You Notice Changes?

You know your body best. If your nails start changing—especially alongside signs like:

• Persistent fatigue
  

• Swollen feet or ankles
  

• Frequent urination (especially at night)
  

• Blood in urine or foamy urine
  

• Unexplained nausea or poor appetite
  

…it’s time to talk to your doctor.

Recommended evaluations include:

• Basic metabolic panel: To assess creatinine, BUN, and electrolyte levels
  

• eGFR test: To determine kidney filtration rate
  

• Urinalysis: To check for protein, blood, or sediment in urine
  

• CBC (Complete Blood Count): To detect anemia

For parents concerned about younger family members, especially if similar signs show up in children, this guide on protein in children's urine offers helpful insights into pediatric kidney markers.

Nail Myths vs. Facts in Kidney Disease

How to Support Nail and Kidney Health Naturally

You can take proactive steps that benefit both your kidneys and your nails.

1. Hydrate Wisely

Drink adequate water to support filtration. Most healthy adults need about 2–3 liters daily unless fluid restriction is advised.

2. Eat Nutrient-Dense Foods

• Iron-rich foods: Lentils, spinach, lean meats
  

• B vitamins: Whole grains, eggs, leafy greens
  

• Omega-3s: Fatty fish, chia seeds, flax
  

• Zinc: Pumpkin seeds, seafood
  
  

These nutrients support nail strength, oxygen delivery, and kidney cell health.

3. Limit Processed Salt and Sugar

• Excess sodium increases blood pressure and damages nephrons.
  

• High sugar contributes to diabetes—a leading cause of CKD.

• Focus on whole foods with minimal additives.

4. Protect Against Protein Loss

• Choose balanced protein intake based on your kidney function.
  

• Avoid high-protein “cleanse” diets unless approved by your nephrologist.
  
  

If you’re losing protein through urine, work with a dietitian.

5. Monitor Iron and Albumin

Anemia and low albumin often affect nails. Blood tests can guide supplementation if needed.

6. Avoid Harsh Nail Treatments

Limit frequent manicures, acrylic nails, and polish removers that damage nail beds, especially if your nails are already fragile.

Real-Life Tip: Track Nail Changes Over Time

Nail growth is slow—about 3 mm per month. That means most visible changes reflect what happened weeks or even months ago.

You might consider:

• Taking periodic nail photos to document changes
  

• Keeping a log of other symptoms and dietary shifts
  

• Reviewing these notes with your healthcare provider
  

Can Nail Health Improve with Kidney Treatment?

In some cases, yes. If the underlying cause—such as anemia or uremia—is treated, nail appearance can improve over time. For others, nail changes may be permanent but harmless.

Treatment that may help includes:

• Iron or B12 supplementation
  

• Erythropoietin-stimulating agents (ESAs)
  

• Dialysis (to remove waste buildup)
  

• Improved nutrition and hydration

If you're wondering about practical ways to test your kidney function regularly, the at-home urine protein test provides an easy, non-invasive way to monitor kidney-related protein loss.

Pay Attention to What Your Nails Say

Your fingernails and toenails can tell a story. While they won’t give you a diagnosis on their own, they can point to issues that deserve deeper attention—especially if you have risk factors for kidney disease.

Half-and-half nails, spooning, white discoloration, and ridging may all be connected to declining kidney function. The earlier you spot these changes and investigate the cause, the better your chances of managing any underlying issues effectively.

Stay Ahead of Kidney Concerns—From Home

Noticing unusual changes in your nails?  Ribbon Checkup’s at-home kidney health test can help you track essential markers like creatinine, eGFR, and BUN—so you can stay informed between appointments and catch early signs of kidney issues before they progress.

Explore the Ribbon Checkup Kidney Test Kit

Written by Abel Tamirat, MD
Dr. Abel Tamirat is a licensed General Practitioner and ECFMG-certified international medical graduate with over three years of experience supporting U.S.-based telehealth and primary care practices. As a freelance medical writer and Virtual Clinical Support Specialist, he blends frontline clinical expertise with a passion for health technology and evidence-based content. He is also a contributor to Continuing Medical Education (CME) programs.

References

Aqil Niema, Nassiri Aicha, Salim, G., & Zahra, M. F. (2019). Nail Disorders in Patients with Chronic Renal Failure. Journal of Dermatology Research and Therapy, 5(1). https://doi.org/10.23937/2469-5750/1510065 

Goel, V., Sil, A., & Das, A. (2021). Cutaneous Manifestations of Chronic Kidney Disease, Dialysis and Post-Renal Transplant. Indian Journal of Dermatology, 66(1), 3–11. https://doi.org/10.4103/ijd.ijd_502_20 

J.C. Robles-Mendez, O. Vazquez-Martinez, & J. Ocampo-Candiani. (2015). Skin manifestations of chronic kidney disease. Actas Dermo-Sifiliográficas, 106(8), 609–622. https://doi.org/10.1016/j.adengl.2015.09.001 

Kidney disease: 11 ways it can affect your skin. (2019). Retrieved May 26, 2025, from Aad.org website: https://www.aad.org/public/diseases/a-z/kidney-disease-warning-signs 

Raja, S. M. (2021). Chronic kidney disease entertained from Lindsay’s nails: A case report and literature review. Clinical Case Reports, 9(7). https://doi.org/10.1002/ccr3.4426