Researchers wanted to know if low vitamin levels or thyroid problems cause a type of permanent hair loss called scarring alopecia. They compared blood test results from 68 people with this condition to 68 healthy people. The study looked at vitamin B12, folate, vitamin D, iron levels, and thyroid function. Surprisingly, they found no meaningful differences between the two groups. This suggests that these vitamin and thyroid issues may not be the main cause of scarring alopecia, though other factors could still play a role in why people develop this condition.

The Quick Take

  • What they studied: Whether low levels of certain vitamins (B12, folate, vitamin D, iron) or thyroid problems cause permanent scarring hair loss
  • Who participated: 68 people (mostly women, average age 47) with scarring alopecia and 68 healthy people without hair loss for comparison
  • Key finding: Blood tests showed no significant differences in vitamin levels or thyroid function between people with scarring hair loss and healthy controls, suggesting these factors may not be the main cause
  • What it means for you: If you have scarring alopecia, taking vitamin supplements based on normal blood levels probably won’t stop the hair loss. However, this doesn’t mean vitamins are never important—other causes may still be involved, and your doctor should still check your levels if you have symptoms

The Research Details

This was a case-control study, which is like comparing two similar groups of people to find differences. Researchers looked back at medical records from 2020 to 2025 and collected blood test results from 68 patients with scarring alopecia (a condition where hair follicles are permanently damaged and destroyed) and compared them to 68 healthy people without this condition. They measured five things in the blood: ferritin (iron storage), folate, vitamin B12, vitamin D, and thyroid hormones. Then they used statistics to see if the numbers were meaningfully different between the two groups.

The patients in the study had different types of scarring alopecia, including lichen planopilaris (the most common type at 45.6%), frontal fibrosing alopecia (29.4%), pseudopelade (16.2%), discoid lupus erythematosus (7.4%), and folliculitis decalvans (1.5%). Most participants were women (91.2%), and people had been dealing with hair loss for an average of about 2.9 years.

This type of study is useful because it lets researchers compare people with a condition to people without it to see what might be different. However, it can only show associations, not prove that one thing causes another.

Understanding what causes scarring alopecia is important because it’s a permanent type of hair loss that can be emotionally difficult for people. If researchers could identify the cause, they might develop better treatments. This study helps rule out vitamin deficiencies and thyroid problems as primary causes, which means doctors should look elsewhere for explanations and treatments.

This study has some strengths: it compared patients to a control group, used objective blood tests, and included a decent number of participants. However, there are limitations to consider: the study only looked at people’s medical records after they already had the condition (not following people over time), most participants were women so results may not apply equally to men, and the study didn’t look at other possible causes like genetics, immune system problems, or infections. The small sample size also means the results might not apply to all people with this condition.

What the Results Show

The main finding was that there were no statistically significant differences in any of the measured nutrients or thyroid markers between people with scarring alopecia and healthy controls. Vitamin B12 levels were nearly identical (340 vs. 357 ng/L), folate levels were almost the same (11.89 vs. 12.23 ng/mL), ferritin levels were similar (34.75 vs. 39.89 µg/L), and vitamin D levels showed no meaningful difference (54.3 vs. 58.59 nmol/L). All of these comparisons had p-values greater than 0.05, which means the differences could easily be due to chance rather than a real biological difference.

Thyroid function tests, which included TSH (thyroid stimulating hormone) and free T4 (a thyroid hormone), were also similar between the two groups. This is important because thyroid problems are sometimes thought to contribute to hair loss, but this study found no evidence of that connection in scarring alopecia patients.

The consistency of these findings across multiple nutrients and thyroid markers suggests that nutritional deficiencies and thyroid dysfunction are probably not the main drivers of scarring alopecia development. However, this doesn’t mean these factors are completely unimportant in all cases.

The study also documented the types of scarring alopecia present in the patient group. Lichen planopilaris was the most common diagnosis, affecting about 45% of patients. This information helps researchers understand which types of scarring alopecia are most prevalent and might help guide future research into different causes for different types. The fact that most patients were women (91.2%) is notable and suggests that scarring alopecia may be more common in women, though this study wasn’t designed to investigate why.

Previous research has suggested that vitamin deficiencies might play a role in various types of hair loss, particularly non-scarring alopecia (like male pattern baldness). However, scarring alopecia appears to be a different type of condition, likely involving immune system inflammation that damages hair follicles permanently. This study supports the idea that scarring alopecia has different causes than other hair loss types. The findings align with growing evidence that scarring alopecia is primarily an inflammatory condition rather than a nutritional problem.

Several important limitations should be considered: First, this was a retrospective study using existing medical records, so researchers couldn’t control what blood tests were done or when. Second, the study only included people who already had scarring alopecia, so it can’t show whether low vitamins might have contributed to developing the condition in the first place. Third, 91% of participants were women, so the results may not apply equally to men with scarring alopecia. Fourth, the study didn’t measure other potential causes like immune system markers, genetic factors, or infections. Finally, with only 68 patients in each group, the study might have missed small but real differences, and results may not apply to all populations or all types of scarring alopecia.

The Bottom Line

Based on this study, taking vitamin supplements to treat scarring alopecia is not recommended as a primary treatment strategy (low confidence for this specific condition). However, if blood tests show you actually are deficient in these nutrients, correcting the deficiency is still important for overall health. The best approach is to work with a dermatologist who can evaluate your specific situation and recommend appropriate treatments, which may include topical medications, injections, or other therapies targeting the underlying inflammation. If you’re concerned about nutrient levels, ask your doctor to test them rather than assuming they’re low.

This research matters most for people with scarring alopecia who are looking for causes and treatments. It’s also relevant for dermatologists treating this condition. People with other types of hair loss (like male pattern baldness) should not assume these findings apply to them, as scarring alopecia appears to have different causes. If you have scarring alopecia, this study suggests you should focus on treatments that address inflammation rather than vitamin supplementation alone.

If you do have vitamin deficiencies and correct them, you might see improvements in general health within weeks to months, but this study suggests it won’t reverse scarring alopecia specifically. Hair regrowth from scarring alopecia treatments, if they work, typically takes several months to become visible. Don’t expect quick results from any treatment for this condition.

Want to Apply This Research?

  • If you have scarring alopecia, track your blood test results for vitamin B12, folate, vitamin D, and ferritin levels every 6-12 months, along with thyroid function tests. Record the dates and values to share with your dermatologist and monitor whether any deficiencies develop over time.
  • Rather than focusing on vitamin supplementation as a treatment, use the app to track your dermatology appointments, prescribed treatments (like topical medications or injections), and any changes in hair loss patterns. This helps you and your doctor see what treatments are actually working for your specific type of scarring alopecia.
  • Set up quarterly reminders to photograph affected areas (for comparison) and to note any changes in symptoms. Track which treatments you’re using and their effects. Keep a log of any new symptoms or concerns to discuss with your dermatologist. This long-term tracking helps identify patterns and treatment effectiveness better than relying on memory.

This study suggests that vitamin deficiencies and thyroid problems are not the primary cause of scarring alopecia, but this does not mean vitamins are never important for hair health or that you shouldn’t have your levels checked if you have symptoms. This research applies specifically to scarring alopecia and should not be interpreted as advice about other types of hair loss. Always consult with a dermatologist or healthcare provider before making decisions about supplementation, testing, or treatment for hair loss. Individual cases may vary, and your doctor can provide personalized recommendations based on your specific situation and medical history.