When Hair Loss Isn't Just About Your Hair

Many people are surprised to learn that hair loss can sometimes be linked to what's happening elsewhere in the body.

A common story we hear at Restore Hair & Scalp Clinic goes something like this:

"My hair started shedding a few months ago, but nothing major changed recently."

The challenge is that hair loss often doesn't happen immediately after the trigger occurs. In fact, the shedding you notice today may be connected to something that happened two or three months ago.

When your body experiences nutritional deficiencies, physical stress, illness, or major dietary changes, it may redirect resources toward essential functions and away from processes it considers less critical for survival—including hair growth.

Why the Body Treats Hair Growth as a Lower Priority

Hair follicles are among the most active structures in the body.

During the growth phase of the hair cycle, follicles require a continuous supply of oxygen, protein, vitamins, minerals, and energy to produce healthy hair strands.

When resources become limited, the body prioritizes:

• Brain function

• Heart function

• Organ health

• Immune function

• Tissue repair

Hair growth becomes secondary.

As a result, more hairs may enter the resting phase (telogen phase) prematurely, eventually leading to increased shedding—a condition commonly known as telogen effluvium.

This process is often a protective response rather than a sign of permanent hair loss.

Understanding the Hair Growth Cycle

Healthy hair grows in cycles.

Anagen (Growth Phase)

This is the active growth stage where follicles continuously produce hair.

Catagen (Transition Phase)

A short phase where growth slows and the follicle begins to shrink.

Telogen (Resting Phase)

Hair remains in place but is no longer actively growing.

Exogen (Shedding Phase)

The old hair sheds, allowing a new hair to begin growing.

When nutritional deficiencies occur, a larger number of hairs may shift into the telogen phase simultaneously, resulting in noticeable shedding weeks or months later.

Iron Deficiency: One of the Most Common Causes of Hair Shedding

Iron plays a critical role in delivering oxygen throughout the body.

Hair follicles depend on adequate oxygen to maintain healthy growth.

Low iron stores—often measured through ferritin levels—are one of the most common nutritional factors associated with diffuse hair shedding, particularly in women.

Common causes of low iron include:

• Heavy menstrual cycles

• Pregnancy and postpartum recovery

• Vegetarian or vegan diets

• Digestive conditions affecting absorption

• Chronic dieting

Many patients are surprised to learn that hemoglobin levels can appear normal while ferritin levels remain too low to optimally support hair growth.

Protein: The Building Block of Hair

Hair is primarily made of keratin, a structural protein.

Without sufficient dietary protein, the body may conserve resources by slowing hair production.

Protein-related shedding may occur after:

• Restrictive dieting

• Rapid weight loss

• Bariatric surgery

• Extremely low-calorie diets

• Inadequate daily protein intake

Because hair growth is not essential for immediate survival, it is often one of the first processes affected by protein shortages.

Vitamin D and Hair Follicle Function

Vitamin D plays an important role in regulating the hair growth cycle.

Research has shown associations between low vitamin D levels and several forms of hair loss, including increased shedding and certain inflammatory scalp conditions.

Vitamin D deficiency is especially common in northern regions where sunlight exposure is limited for significant portions of the year.

Potential signs of low vitamin D include:

• Fatigue

• Muscle weakness

• Frequent illness

• Increased hair shedding

  
  

Zinc and Hair Health

Although less common than iron deficiency, zinc is another nutrient that supports healthy follicle function.

Zinc contributes to:

• Tissue repair

• Follicle maintenance

• Cellular growth

• Immune regulation

Low zinc levels may contribute to prolonged shedding and slower recovery from hair loss triggers.

The Role of B Vitamins

Several B vitamins support healthy hair growth, particularly:

• Vitamin B12

• Folate (Vitamin B9)

These nutrients help with:

• Red blood cell production

• Oxygen transport

• Cell turnover

• DNA synthesis

Individuals following plant-based diets may be at greater risk for B12 deficiency if supplementation is inadequate.

Why "Normal" Bloodwork Doesn't Always Tell the Full Story

One of the most common frustrations patients express is:

"My bloodwork was normal, but my hair is still falling out."

While laboratory reference ranges are valuable, they are designed to identify disease—not necessarily optimal conditions for hair growth.

For example, ferritin levels may fall within the laboratory's normal range while still being lower than what some hair specialists consider ideal for supporting healthy follicles.

This is one reason why a comprehensive assessment is important when investigating hair loss.

Which Lab Tests May Be Worth Discussing With Your Healthcare Provider?

If increased shedding is a concern, you may wish to discuss testing with your healthcare provider, including:

• Ferritin (iron stores)

• Vitamin D

• Vitamin B12

• Folate

• Thyroid Stimulating Hormone (TSH)

• Complete Blood Count (CBC)

These tests can help identify potential contributing factors and guide appropriate treatment recommendations.

Can Supplements Stop Hair Loss?

Not necessarily.

This is an important point.

Supplements can be helpful when a true deficiency exists, but taking excess amounts of vitamins or minerals does not automatically improve hair growth.

In some cases, excessive supplementation may even create new problems.

The goal should be identifying and correcting deficiencies—not simply adding more supplements.

When Should You Seek Professional Help?

If you have noticed:

• Increased shedding for more than three months

• Hair coming out in large amounts while washing or brushing

• Visible thinning along the part line or crown

• Hair loss following illness, stress, surgery, or dieting

A professional Hair & Scalp Analysis can help determine whether nutritional factors, hormonal changes, genetics, scalp conditions, or other causes may be contributing to the issue.

Final Thoughts

Hair loss is often the body's way of signaling that something deeper deserves attention.

Iron deficiency, low protein intake, vitamin D insufficiency, and other nutritional factors can all affect the hair growth cycle. Because shedding often appears months after the original trigger, identifying the underlying cause requires looking beyond the hair itself.

Understanding the connection between nutrition and follicle health is an important first step toward creating an effective plan for recovery.