RegrowProtocol

Tool

Blood-Test Request Builder for Hair Loss

what blood tests should I ask for, and what is a good ferritin level for hair growth

Two things make a blood-test appointment go badly: not knowing what to ask for, and being told a result is "normal" when the guides put it well below the level associated with hair growth. many doctors order incomplete panelsDL02 Standard laboratory reference ranges are designed to identify disease, not optimize health.DL02 So this builds the list, and then shows you the bands the guides publish for the three numbers people actually ask about.

Sex

This only decides whether cycle-timing notes and the hormone add-ons appear.

Anything else going on?

Tick what applies. Each tick adds the tests the guides attach to that sign — nothing is removed from the core panel.

The list to ask for

Core panel 8

On the list whatever your symptoms are.

  • Complete Blood Count (CBC) Measures red blood cells, white blood cells, hemoglobin, and platelets.DL02 present in 25-30% of hair loss patientsDL02
  • Ferritin Ferritin reflects your body’s iron reserves better than serum iron alone.DL02 affecting up to 40% of women with thinning hairDL02
  • Serum iron with TIBC Serum iron measures circulating iron; Total Iron Binding Capacity (TIBC) shows how much iron your blood could carry.DL02
  • TSH TSH is the screening test for thyroid function.DL02 Both hypothyroidism and hyperthyroidism disrupt the hair growth cycle, affecting roughly 15% of people with hair lossDL02
  • Free T4 Free T4 provides additional information about active thyroid hormone.DL02
  • Vitamin D (25-hydroxyvitamin D) The 25-hydroxyvitamin D test [25(OH)D] is the only reliable way to assess vitamin D status.DL07 Vitamin D deficiency appears in approximately 80% of alopecia patientsDL02
  • Vitamin B12 B12 deficiency causes hair loss and is more common than many realizeDL02 B12 · "Normal" Range 200-900 pg/mL · Optimal for Hair >400 pg/mLW08
  • Zinc Zinc is essential for hair follicle function and protein synthesis.DL02 Zinc · "Normal" Range 70-120 µg/dL · Optimal for Hair 80-100 µg/dLW08

Timing, so the numbers mean something

  • Ferritin and iron studies Best: Fasting or at least 2 hours after eatingW08
  • Ferritin and iron studies Iron supplements can falsely elevate; stop 24-48 hours before testingW08
  • Thyroid tests Best: Morning, fastingW08
  • Thyroid tests Biotin supplements can interfere—stop 2-3 days beforeW08
  • Thyroid tests Stop biotin supplements at least 2 days before testing (some sources recommend 3-7 days)DL06
  • Thyroid tests If on thyroid medication, test before taking your morning doseDL06
  • Vitamin D Any time, no special preparationW08
  • Retesting Retest ferritin after 8-12 weeks, vitamin D after 3 months, and thyroid markers after 6-12 weeks if on medication.DL02

Hand this over

Bring a list: Know exactly which tests you wantW08


      

        
        
      

    

  


  

    
Already have results?

    
Type a number in and this shows which published band it falls in, and the sentence that
    band comes from. That is all it does. It is not a reading of your health, and the bands are the guides’,
    not your laboratory’s. Blood test interpretation requires clinical context.W08

    
    

      

        
        
      

      
      
      
Enter a value to see which band the guide puts it in.

      

        

          
Critical deficiency (<20 ng/mL) DL05

          
Hair loss very likely to be occurring or imminent.DL05

        

          
Suboptimal (20-40 ng/mL) DL05

          
Hair loss probable or contributing factor.DL05

        

          
Adequate for hair (40-60 ng/mL) DL05

          
Minimum level to support hair growth.DL05

        

          
Good for hair (60-70 ng/mL) DL05

          
Supports healthy hair growth.DL05

        

          
Optimal for hair (70-100 ng/mL) DL05

          
Ideal for hair density and growth.DL05

        

      

      
Outside that range: Ferritin above 200 ng/mL without supplementation (may indicate iron overload or inflammation)DL05

    

    

      

        
        
      

      
      
      
Enter a value to see which band the guide puts it in.

      

        

          
Low TSH (below 0.4 mIU/L) DL02

          
Suggests hyperthyroidism.DL02

        

          
Lab normal: 0.4-4.0 mIU/L DL06

          
AACE recommends: 0.3-3.0 mIU/LDL06

        

          
Optimal for symptoms: 0.5-2.5 mIU/L DL06

          
AACE recommends: 0.3-3.0 mIU/LDL06

        

          
Many people continue experiencing fatigue, cold intolerance, and hair loss when their TSH is technically "normal" (say, 3.5) but not optimal. DL06

          
Lab normal: 0.4-4.0 mIU/LDL06

        

          
"High-normal" (3.5-4.5): May indicate subclinical hypothyroidism W08

          
Lab normal: 0.4-4.0 mIU/LDL06

        

          
Elevated TSH (above 4.0 mIU/L) DL02

          
Even "subclinical" hypothyroidism (TSH 4-10 with normal T4) can cause hair thinning.DL02

        

      

      
    

    

      

        
        
      

      
      
      
Enter a value to see which band the guide puts it in.

      

        

          
<20 · Deficient · High risk of hair loss; requires correction DL07

          
Levels below 20 ng/mL significantly increase the risk of telogen effluviumDL07

        

          
20-29 · Insufficient · Suboptimal; may contribute to thinning DL07

          
Many people continue losing hair with levels in the 20-29 ng/mL rangeDL07

        

          
30-50 · Optimal · Best range for hair health and immune function DL07

          
Optimal vitamin D level for hair health is 30-50 ng/mLDL07

        

          
50-100 · Adequate · Safe; may not provide additional benefit DL07

          
The Endocrine Society Clinical Practice Guidelines (2011) identified 30-100 ng/mL as the desirable range, with 21-29 ng/mL considered insufficient and <20 ng/mL deficient.DL07

        

      

      
Outside that range: >100 · Excessive · Risk of toxicity; avoidDL07

    


    

      Our own guides do not agree on the vitamin D target
      
Three of the drafts behind this tool give three different optimal ranges. Rather than pick one,
      here are all three with their sources:

      
    
        
  • DL07Optimal vitamin D level for hair health is 30-50 ng/mLDL07
    • 
        
  • W08Optimal: 40-60 ng/mLW08
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  • DL0250-80 ng/mL is ideal for most peopleDL02
    • 
      

      
The scale above uses DL07’s bands, because DL07 is the vitamin D guide. The disagreement is
      real and worth knowing about before you argue a number with anyone.

    


    

      Context for the three numbers
      
    
        
  • FerritinLaboratory "normal" ferritin (10-15 ng/mL) is too low for optimal hair growthDL05Using 41 ng/mL as the cutoff yields 98% sensitivity and 98% specificityDL05
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  • FerritinResearch suggests best outcomes at ferritin levels of 70 ng/mL or higher.DL05Women with telogen effluvium had mean ferritin of 14.7 ng/mL vs 43.5 ng/mL in controlsW08
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  • Ferritiniron deficiency was the most prevalent etiology of female hair loss, accounting for 70.3% of casesW08You can have iron deficiency hair loss WITHOUT anemia.W08
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  • TSHMany people continue experiencing fatigue, cold intolerance, and hair loss when their TSH is technically "normal" (say, 3.5) but not optimal.DL0650% of people with hyperthyroidism and 33% with hypothyroidism experience hair lossDL06
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  • TSHRequest TSH, Free T4, Free T3, TPO antibodies, and TG antibodies.DL0617.3% of women with female pattern hair loss had elevated anti-TPO antibodiesW08
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  • Vitamin D56% of people with androgenetic alopecia have vitamin D deficiency (vs 24% in controls)DL07
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  • HormonesPCOS affects 11-13% of women globallyW05This affects 60-80% of women with PCOSW05
    • 
      

    


    

      What the guides say not to bother with
      
    
        
  • Comprehensive metabolic panels, liver function, and kidney function are good to have but rarely directly explain hair loss.DL02
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  • Genetic testing for hair loss is available but doesn’t change treatment decisions. Heavy metal testing is popular but rarely clinically useful.DL02
    •