Half Moon Nails: Why You Do Or Don't Have It, Symptoms To Watch For

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What Does It Mean to Have Half Moons on Your Nails?Medically reviewed by Megan Slomka, MSN, APRN, FNP-C — Written by Mariah Adcox — Updated on August 1, 2025

Healthy half-moon
Symptoms to watch for
Small or missing moons
Large half-moons
Speak with a doctor
The bottom line

In many cases, seeing a half-moon shape at the base of your fingernail isn’t a cause for concern. However, if you notice any changes to it, it’s important to speak with a doctor.

The half-moon shape at the base of your fingernail is known as a lunula. Lunulae cover the bottom of your nail, just above your cuticle.

They are part of your nail matrix, which refers to the tissue just beneath your nail. It contains nerves, lymph, and blood vessels. It also produces the cells that become the hardened nail plate, which is what you see.

Although everyone has a nail matrix, not everyone will see or have a lunula on each nail. Those who do have a lunula may notice that they vary in appearance across each nail.

Read on to learn more about what these half-moons look like, when their appearance could be cause for concern, and when to speak with a doctor.

What do healthy lunulae look like?

Healthy lunulae are usually a whitish color and take up a small portion of the bottom of your nail. They’re usually most visible on your thumb.

You may notice that they appear smaller on your pointer finger, gradually shrinking in size until you reach your pinkie where they may be barely visible.

What causes abnormal coloring?

Sometimes, the appearance of your lunula or overall nail can be a sign of an underlying condition.

Here are some of the most common reasons for abnormal lunulae:

Tetracycline therapy

Tetracycline medications are antibiotics that are usually used to treat acne and skin infections. Extended use may cause your lunulae to turn yellow.

Silver poisoning

Blue-grey lunulae may be a sign of silver poisoning.

Yellow nail syndrome

This condition typically produces thick, slow growing nails. The middle of your nail may begin to rise, causing the lunulae to disappear completely. Your entire nail may take on a yellow appearance.

Terry’s nails

This condition causes the bulk of your nail to appear white, completely erasing the appearance of the lunula. It’s characterized by a pink or red band of separation near the arc of your nails. Although it can happen on one finger only, it usually affects all fingers.

In older adults, this condition is usually a natural sign of aging.

Wilson’s disease

This is a rare inherited disorder that occurs when too much copper accumulates in your organs. It’s known to cause blue lunulae.

What does it mean if my lunulae are small or missing?

Small or missing lunulae usually aren’t a cause for concern. They’re usually just hidden underneath the cuticle or skin at the base of your finger.

In some cases, missing lunulae may be a result of trauma or a sign of anemia or malnutrition.

If you’re experiencing other unusual symptoms, such as fatigue or overall weakness, consider speaking with a doctor. They can perform a physical exam to help diagnose the cause of your symptoms and advise you on next steps.

What if my lunulae are large?

Researchers don’t know what causes the lunula to take up a significant portion of the nail.

Some reports suggest that lunulae may signal issues with the cardiovascular system, such as heartbeat disruption and low blood pressure.

Unscientific theories claim that large lunulae may be common in athletes and people who engage in lots of physical activity. This may be due to the bodily stress associated with high-impact activities, but there is currently no research to back up these claims.

When to seek medical support

Discolored or missing lunulae usually aren’t cause for concern. But if you notice changes in your nail appearance and are experiencing other unusual symptoms, make an appointment to see a doctor.

You should seek immediate medical attention if your hands and feet are also turning blue. This could be a sign of cyanosis, a condition that results from poor circulation or inadequate oxygenation of your blood.

Your doctor can assess your symptoms and advise you on treatment options. Treating the underlying condition will usually restore your nail appearance and improve your overall well-being.

The bottom line

In many cases, seeing a half-moon shape at the base of your fingernail isn’t a cause for concern.

However, sometimes, the appearance of your lunula or overall nail can be a sign of an underlying condition. If you notice changes in your nail appearance and are experiencing other unusual symptoms, speak with a doctor.

How we reviewed this article:

SourcesHistoryHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

12 nail changes a dermatologist should examine. (n.d.).https://www.aad.org/public/everyday-care/nail-care-secrets/basics/nail-changes-dermatologist-should-examine
Basu P, et al. (2018). Macrolunula: Case reports of patients with trauma-associated enlarged lunula and a concise review of this nail finding.https://pmc.ncbi.nlm.nih.gov/articles/PMC6143371/
Cheslock M, et al. (2022). Yellow nail syndrome.https://www.ncbi.nlm.nih.gov/books/NBK557760/
Kayıran M, et al. (2021). Fluorescence of nails and hair on Wood's lamp examination in Covid pandemic; undefined effect of Favipiravir in humans.https://pmc.ncbi.nlm.nih.gov/articles/PMC7883070/
Reinecke JK, et al. (2020). Nail health in women.https://pmc.ncbi.nlm.nih.gov/articles/PMC7105659/
Steck MB, et al. (2022). Silver toxicity.https://www.ncbi.nlm.nih.gov/books/NBK604211/
Wilson disease. (n.d.).https://www.niddk.nih.gov/health-information/liver-disease/wilson-disease
Witkowska AB, et al. (2017). Terry's nails: A sign of systemic disease.https://pmc.ncbi.nlm.nih.gov/articles/PMC5448267/

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Medically reviewed by Megan Slomka, MSN, APRN, FNP-C — Written by Mariah Adcox — Updated on August 1, 2025

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