Does B12 Make Your Hair and Nails Grow?

January 1, 2026 •

4 min read

According to the National Institutes of Health, vitamin B12 is an essential nutrient needed for red blood cell formation, nerve function, and DNA synthesis. Its role in these fundamental cellular processes is why many people wonder if it can directly affect the growth of hair and nails.

Quick Summary

Vitamin B12 is crucial for supporting the cellular functions that underpin healthy hair and nail growth, particularly red blood cell production. While it doesn't directly stimulate growth in non-deficient individuals, a B12 deficiency can lead to hair thinning, nail discoloration, and slow growth. Restoring healthy B12 levels can reverse these adverse effects and promote better overall health.

Key Points

Indirect Impact: B12 supports hair and nail growth indirectly by assisting in vital cellular functions, not by acting as a direct growth stimulant.
Red Blood Cell Production: B12 is essential for producing red blood cells, which carry oxygen and nutrients to hair follicles and nail beds. A deficiency impairs this process.
Reversible Symptoms: Hair thinning, premature greying, and nail discoloration caused by a B12 deficiency are often reversible with proper supplementation.
Deficiency Correction: The primary benefit of B12 for hair and nails is in correcting a pre-existing deficiency, which can cause significant issues in their health and appearance.
Holistic Approach: Optimal hair and nail health depend on a balanced diet of various nutrients, including B12, biotin, iron, and zinc, not just one single vitamin.
Professional Guidance: Before starting B12 supplements, it is crucial to consult a healthcare professional to confirm a deficiency and determine the correct dosage.

The Indirect Link Between B12 and Hair Growth

Vitamin B12, or cobalamin, is not a magic pill for accelerated hair growth. Instead, its influence is foundational and indirect, relying on its critical role in red blood cell formation and DNA synthesis. These processes are vital for the health of hair follicles, the tiny organs in your skin responsible for producing hair strands. When red blood cell production is hindered due to a B12 deficiency, less oxygen is transported to the scalp and hair follicles. This lack of oxygen and nutrients can weaken follicles, disrupt the normal growth cycle, and lead to problems like excessive shedding and thinning.

For those with a confirmed deficiency, restoring adequate B12 levels can correct these issues, leading to improved hair growth and strength. Studies have noted the link between low B12 levels and diffuse hair loss, suggesting that supplementation can be a key part of treating deficiency-related hair problems. However, it is a misconception that simply taking extra B12 will cause faster or thicker hair growth in someone who already has sufficient levels.

How a B12 Deficiency Affects Hair Health

A deficiency can impact hair health in several ways:

Slowed Cell Division: B12 is essential for producing DNA and enabling the cell replication needed for hair to grow from follicles. Without enough B12, cell proliferation can slow down significantly.
Disrupted Blood Flow: Insufficient red blood cell production leads to poor oxygen and nutrient supply to the hair follicles, impairing their function.
Premature Greying: In some cases, a B12 deficiency can interfere with melanin production, the pigment responsible for hair color. Restoring B12 levels has been shown to reverse premature greying in specific instances.

The Effect of B12 on Nail Strength and Appearance

Similar to its effect on hair, B12 does not supercharge nail growth but is crucial for maintaining their health. Nails are made of keratin, and their growth depends on a steady supply of nutrients and oxygen delivered via the bloodstream. A B12 deficiency can manifest in visible nail changes, including discoloration and increased fragility.

For example, low B12 levels can reduce red blood cell production, leading to anemia. This can manifest as pale, yellowish, or even bluish nails due to decreased oxygen supply to the nail beds. The nails may also become weak, brittle, or develop vertical ridges. By correcting a deficiency, these symptoms can often be reversed, and the nails can return to their healthy state.

Addressing Nail Issues Caused by B12 Deficiency

To improve nail health, it's important to ensure adequate B12 intake. The best way is through a balanced diet, but those with absorption issues or dietary restrictions may require supplements or injections. A healthcare provider can determine the appropriate course of action based on blood test results.

Dietary Adjustments: Include foods rich in B12, such as meat, fish, dairy, and eggs. Fortified cereals and nutritional yeast are also options, especially for vegans and vegetarians.
Hydration: Staying hydrated is also key for nail health, as well-hydrated nails are less prone to brittleness and breakage.
Supplementation: If diet is not enough, a doctor may recommend oral supplements or B12 injections to rapidly restore levels.

Comparison of B12 vs. Other Nutrients for Hair and Nail Health


Nutrient	Primary Function for Hair/Nails	Deficiency Symptoms	Best for Improvement (When Deficient)
Vitamin B12	Red blood cell formation; cell division.	Hair loss, slow hair growth, brittle/discolored nails.	Overall cellular health, reversing deficiency symptoms.
Biotin (B7)	Supports keratin production.	Hair loss, brittle nails.	Strengthening hair and nails, especially for known deficiency.
Iron	Carries oxygen to cells via red blood cells.	Hair loss, brittle or 'spooned' nails.	Restoring oxygen delivery and preventing anemia.
Zinc	Essential for cell growth and division.	Hair loss, white spots on nails.	Healthy cell growth and division for hair follicles and nail beds.
Protein	Keratin is the main protein building block.	Weak, brittle nails.	Building strong, resilient nail and hair structures.

Conclusion: The Broader Picture of B12

While the idea that B12 directly causes rapid hair and nail growth is a myth, its role in overall cellular function makes it an indispensable component for their health. The key takeaway is that B12 plays a supportive, not a stimulant, role. A deficiency can lead to hair loss and weakened, discolored nails, and in these cases, addressing the shortfall will lead to visible improvements. For individuals with no deficiency, excessive B12 supplementation is unlikely to have a noticeable effect on growth and is unnecessary. As with any supplement regimen, it is best to consult a healthcare professional to determine if you have a deficiency and what the appropriate treatment should be. Ensuring a balanced diet and addressing any underlying health issues are the most effective ways to promote robust hair and nail vitality.

Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice. Always consult a healthcare provider for any health concerns or before starting a new supplement regimen.

Frequently Asked Questions

If you have a confirmed B12 deficiency, supplements can help restore normal hair growth by correcting the deficiency. However, if your B12 levels are already sufficient, taking more is unlikely to increase your hair growth rate.

Signs can include hair loss, thinning hair, slow growth, and premature greying. For nails, symptoms can include brittleness, discoloration (pale, yellowish, or bluish), and the development of ridges.

B12 deficiency disrupts the body's ability to produce healthy red blood cells and synthesize DNA, which affects cell division. This starves hair follicles and nail beds of the oxygen and nutrients needed for proper growth and health.

Both B12 and biotin (B7) are important, but for different reasons. Biotin directly supports the production of keratin, the protein that makes up hair and nails. B12's role is more foundational, supporting the cellular processes that allow for healthy growth. Neither is superior, and a holistic approach considering multiple nutrients is best.

B12 injections are often used for severe deficiencies or when absorption issues, like pernicious anemia, are present, as they bypass the digestive system. For mild to moderate deficiencies, oral supplements can be effective.

Good dietary sources of vitamin B12 include meat, poultry, fish, eggs, dairy products, and fortified cereals.

Changes happen gradually. Some people notice reduced hair shedding within a few weeks, but visible improvements in hair thickness and nail strength can take several months, as it depends on new growth.