Does LDN Cause Hair Loss?

Yoon Hang Kim MD

Quick Answer: Does LDN Cause Hair Loss?

No direct evidence exists that LDN causes hair loss as a primary side effect

Clinical trials consistently list vivid dreams, sleep changes, and headaches as the most common side effects

Hair loss in LDN patients typically relates to the underlying autoimmune condition, thyroid imbalance, or nutritional deficiency

LDN may actually help certain types of autoimmune hair loss, with studies showing disease stabilization in 70-80% of patients with frontal fibrosing alopecia

Timing matters: Hair loss occurring 2-3 months after a trigger may be Telogen Effluvium, a temporary stress response

The relationship between low-dose naltrexone and hair health is far more complex than a simple cause-and-effect. For most people experiencing hair thinning while on LDN, the real culprit is usually the autoimmune condition, thyroid imbalance, nutritional deficiency, or stress that prompted LDN treatment in the first place.

I'm Dr. Yoon Hang Kim, a board-certified physician specializing in integrative medicine and functional medicine who has prescribed and refined LDN protocols for over two decades across conditions ranging from autoimmune disorders to chronic pain. In my extensive clinical experience with patients concerned about LDN and hair loss, I've found that most cases stem from undertreated thyroid issues, iron deficiency, or the autoimmune process itself rather than the medication. Let's explore what the science really shows and how to approach hair health when taking LDN.

Does LDN Cause Hair Loss? Unpacking the Evidence

The scientific evidence regarding whether LDN causes hair loss is nuanced. While some individuals report hair changes on LDN, this isn't a commonly recognized side effect in clinical studies.

Standard-dose naltrexone (50mg and above) has occasionally been associated with hair loss, though it's uncommon. Low-dose naltrexone (0.5-4.5mg) works through an entirely different mechanism, focusing on immune modulation and endorphin upregulation rather than sustained opioid receptor blockade. Published studies investigating LDN across fibromyalgia, multiple sclerosis, and inflammatory bowel disease consistently track adverse events but rarely mention hair loss among significant findings (Younger et al., 2014; Toljan & Vrooman, 2018).

The known side effects of LDN are typically mild and transient: vivid dreams occur in approximately 20-30% of patients, along with occasional sleep disturbances and headaches. These typically resolve within the first few weeks of treatment as the body adjusts.

Potential Indirect Links

While LDN doesn't directly cause hair loss, indirect connections may exist. Temporary hormonal shifts or endocrine adjustments during the initial weeks of LDN therapy could, in sensitive individuals, contribute to hair shedding. More commonly, patients experiencing hair loss concerns while on LDN may have Telogen Effluvium—a stress-induced shedding pattern that appears 2-3 months after a physiological trigger. The trigger may have been the illness that led them to seek LDN treatment in the first place.

Anecdotal Reports vs. Clinical Data

Patient forums contain stories linking LDN to hair loss, but controlled trials tell a different story. Multiple studies across fibromyalgia, multiple sclerosis, and Crohn's disease carefully track adverse events yet consistently omit hair loss from significant findings. This discrepancy suggests anecdotal reports likely reflect underlying conditions rather than LDN effects.

The Real Culprits: When It's Not the LDN

In my practice at www.directintegrativecare.com, serving patients across Iowa, Illinois, Missouri, Florida, Georgia, and Texas, I find that hair loss often signals deeper imbalances rather than medication effects. The conditions that bring patients to LDN in the first place frequently cause hair loss themselves.

Type of Hair Loss	Typical Triggers/Causes
Telogen Effluvium	Temporary diffuse shedding 2-3 months after stress, illness, surgery, or medication changes
Autoimmune Conditions	Hashimoto's thyroiditis, Alopecia Areata, and Lupus can directly attack hair follicles
Thyroid Imbalance	Both hypothyroidism and hyperthyroidism cause dry, brittle, diffusely thinning hair
Iron Deficiency	Low ferritin impairs hair follicle proliferation even without frank anemia
Nutritional Deficiencies	Low zinc, vitamin D, B12, and protein all impair healthy hair growth

Iron Deficiency: A Hidden Cause of Hair Loss

When patients come to me worried that LDN is causing their hair loss, one of the first things I investigate is their iron status. Iron deficiency is remarkably common—especially in women of childbearing age—and frequently flies under the radar because most practitioners only check hemoglobin. You can have perfectly normal hemoglobin and still be profoundly iron deficient.

The Ferritin-Hair Connection

Iron is essential for DNA synthesis in rapidly dividing cells, and hair follicle matrix cells are among the fastest-dividing cells in the human body. When iron stores drop, your body prioritizes vital organs, and hair follicles lose the competition. Research from China examining 193 patients with telogen effluvium found that serum ferritin levels were significantly lower in hair loss patients compared to healthy controls, with an optimal diagnostic cutoff around 24.5 ng/mL (Cheng et al., 2021).

Here's what I've learned from two decades of clinical practice: the laboratory "normal" range for ferritin is not the same as the "optimal" range for hair health. Most labs report ferritin as normal anywhere from 12-150 ng/mL in women. But in functional medicine, we've found that hair follicles often need ferritin levels above 70 ng/mL to function optimally (Rushton, 2002).

Who's at Risk?

A systematic review and meta-analysis examining iron deficiency in women with nonscarring alopecia found that approximately 21% of women with hair loss had ferritin deficiency, and the prevalence increased substantially when using a higher threshold of 30-40 ng/mL (Treister-Goltzman et al., 2022). Risk factors for iron deficiency that I commonly see in my practice include heavy menstrual periods, vegetarian or vegan diets without adequate supplementation, gastrointestinal conditions affecting absorption (particularly relevant for my MCAS patients), chronic inflammation, and recent blood donation.

The Functional Medicine Approach to Iron Assessment

When evaluating a patient with hair loss, I order a comprehensive iron panel rather than just ferritin alone. This includes serum iron, total iron-binding capacity (TIBC), transferrin saturation, and ferritin. Ferritin can be falsely elevated in inflammatory conditions—particularly relevant for patients with autoimmune conditions or chronic infections—so the complete picture matters.

For my patients with low ferritin and hair loss, I typically recommend iron supplementation with vitamin C to enhance absorption, alongside addressing any underlying causes of deficiency. Patience is essential: hair growth cycles are long, and it typically takes 3-6 months of optimized iron stores before visible improvement occurs.

The Flip Side: Can LDN Actually Treat Hair Loss?

While some people worry about LDN causing hair loss, a growing body of evidence suggests it may actually be an effective treatment for certain types of hair loss, particularly those with an autoimmune component. By modulating the immune system and reducing inflammation, LDN can help calm the overactive immune response that targets and damages hair follicles.

Evidence for LDN in Autoimmune Alopecia

LDN's ability to increase endorphin production and regulate T-regulatory cells can be particularly beneficial for autoimmune-driven hair loss. The most compelling evidence comes from studies on frontal fibrosing alopecia (FFA) and lichen planopilaris (LPP), both scarring forms of alopecia.

A retrospective study from the University of Pittsburgh examining 52 patients with FFA and LPP who had failed multiple prior treatments found remarkable results with LDN. For patients with FFA, 75% achieved disease stability within 6.4 months, with significant improvements in pruritus and perifollicular erythema. For LPP patients, 65% achieved disease stability within 7.3 months (Yossef & English, 2024).

A prospective open-label study from Washington University enrolled 43 patients with FFA and LPP and followed them for 12 months on 3mg daily LDN. The frontal hairline remained stable in FFA patients throughout the study period, with significant improvements in itching, burning, and erythema scores (Hamel et al., 2023).

Conditions Where LDN Shows Promise

Alopecia Areata: This autoimmune condition where the body attacks its own hair follicles, causing patchy hair loss, may benefit from LDN's immune-modulating effects. While formal trials are limited, the mechanism of action aligns well with the disease pathophysiology (Mesinkovska, 2018).

Lichen Planopilaris and Frontal Fibrosing Alopecia: These scarring alopecias characterized by inflammation show the most robust evidence for LDN benefit. Multiple studies demonstrate that LDN can halt progression and, in some cases, promote regrowth in follicles not yet permanently damaged.

Trichodynia (Scalp Pain/Discomfort): Even in patients where LDN doesn't produce measurable hair regrowth, many report significant improvement in scalp discomfort, itching, and burning (Tortelly et al., 2019).

Dosage and Timelines for Hair Restoration

When used for hair loss, LDN is typically prescribed in the same low-dose range as for other autoimmune conditions. Based on my clinical experience and the published literature, I usually start patients at 1.5mg and gradually increase to a target dose of 4.5mg per day. The University of Pittsburgh study used 4.5mg daily in most patients, while the Washington University study used 3mg daily—both with positive outcomes.

Patience is essential. Hair growth cycles are long, typically 2-7 years for scalp hair. While some patients notice a reduction in shedding and scalp inflammation within 4-6 weeks, visible regrowth usually takes 3-6 months or longer. Optimal results are often seen after at least 6-12 months of consistent use.

Practical Summary: LDN and Hair Health

Clinical Scenario	Recommended Approach
Hair loss started on LDN	Investigate underlying causes: thyroid, ferritin, nutritional status, autoimmune markers
Autoimmune hair loss (FFA/LPP)	LDN 3-4.5mg daily; expect 6+ months for disease stabilization
Low ferritin with hair loss	Optimize ferritin to >70 ng/mL; continue LDN if indicated for underlying condition
Telogen effluvium pattern	Identify trigger (illness, stress, surgery); reassure that LDN is unlikely the cause; typically self-resolving

Conclusion - Does LDN Cause Hair Loss? Integrative Medicine & Functional Medicine Perspective

The question "Does LDN cause hair loss?" has a nuanced answer. Based on published research and my two decades of clinical experience, LDN does not appear to directly cause hair loss. Rather, patients experiencing hair changes while on LDN typically have underlying conditions—autoimmune disease, thyroid dysfunction, iron deficiency, or nutritional imbalances—that are the true culprits.

In fact, for patients with autoimmune-related hair loss like frontal fibrosing alopecia, lichen planopilaris, and potentially alopecia areata, LDN may be part of the solution rather than the problem. The key is individualized assessment, addressing all contributing factors, and working with a practitioner experienced in both LDN and the complex interplay of autoimmunity, hormones, and nutritional status.

For patients struggling with hair loss alongside chronic complex conditions, working with a physician experienced in LDN, integrative medicine, and functional medicine can make the difference between frustration and meaningful improvement.

About the Author

Yoon Hang Kim, MD is a board-certified preventive medicine physician specializing in integrative and functional medicine. A graduate of the University of Arizona Integrative Medicine Fellowship, Dr. Kim has been prescribing LDN for over two decades and has presented at multiple LDN Research Trust conferences internationally. He is the author of two books on LDN therapy and practices telemedicine through www.directintegrativecare.com, serving patients in Iowa, Illinois, Missouri, Georgia, Florida, and Texas.

Website: www.directintegrativecare.com

References

(Verified and Corrected - APA 7th Edition)

Cheng, T., Fang, H., Wang, Y., Wang, Y., Yang, Z., Wu, R., & Yang, D. (2021). The diagnostic value of serum ferritin for telogen effluvium: A cross-sectional comparative study. Clinical, Cosmetic and Investigational Dermatology, 14, 137-141. https://doi.org/10.2147/CCID.S291170

Hamel, R. K., Chen, L., O'Connell, C., & Mann, C. (2023). Oral low-dose naltrexone in the treatment of frontal fibrosing alopecia and lichen planopilaris: An uncontrolled open-label prospective study. Cureus, 15(1), e34169. https://doi.org/10.7759/cureus.34169

Mesinkovska, N. A. (2018). Emerging unconventional therapies for alopecia areata. Journal of Investigative Dermatology Symposium Proceedings, 19(1), S32-S33. https://doi.org/10.1016/j.jisp.2017.10.012

Olsen, E. A., Reed, K. B., Cacchio, P. B., & Caudill, L. (2010). Iron deficiency in female pattern hair loss, chronic telogen effluvium, and control groups. Journal of the American Academy of Dermatology, 63(6), 991-999. https://doi.org/10.1016/j.jaad.2009.12.006

Rushton, D. H. (2002). Nutritional factors and hair loss. Clinical and Experimental Dermatology, 27(5), 396-404. https://doi.org/10.1046/j.1365-2230.2002.01076.x

Toljan, K., & Vrooman, B. (2018). Low-dose naltrexone (LDN)—Review of therapeutic utilization. Medical Sciences, 6(4), 82. https://doi.org/10.3390/medsci6040082

Tortelly, V. D., De Mattos, T., Fernandes, L. S. A., Nunes, B. E. M., & Melo, D. F. (2019). Low-dose naltrexone: A novel adjunctive treatment in symptomatic alopecias? Dermatology Online Journal, 25(9). https://escholarship.org/uc/item/6j45h81f

Treister-Goltzman, Y., Yarza, S., & Peleg, R. (2022). Iron deficiency and nonscarring alopecia in women: Systematic review and meta-analysis. Skin Appendage Disorders, 8(2), 83-92. https://doi.org/10.1159/000519952

Younger, J., Parkitny, L., & McLain, D. (2014). The use of low-dose naltrexone (LDN) as a novel anti-inflammatory treatment for chronic pain. Clinical Rheumatology, 33(4), 451-459. https://doi.org/10.1007/s10067-014-2517-2

Yossef, S. M., & English, J. C., III. (2024). Attenuation of disease process following treatment with low-dose naltrexone in patients with frontal fibrosing alopecia and lichen planopilaris: A retrospective study. Journal of the American Academy of Dermatology, 91(1), 141-142. https://doi.org/10.1016/j.jaad.2024.03.010

Disclaimer: This publication is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting or modifying any treatment regimen.

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