Hair loss, or alopecia, can affect the scalp or the entire body and may be temporary or permanent. It can result from genetics, hormonal changes, medical conditions, or aging. While men often experience receding hairlines and baldness, women can also face hair loss due to factors like thyroid issues, hormone levels, medications, or autoimmune diseases. Accurate diagnosis by a specialist is essential for effective treatment, and genetic testing can help determine the best medication options.

Common types of hair loss, causes and medication

Pattern baldness

Pattern baldness (androgenetic alopecia) is caused by genetic and hormonal factors related to testosterone. It is most common among men but can affect women as well. This condition is influenced by many genes, with over 400 risk factors identified. There are many treatments for hair loss, such as creams and tablets. Most of these treatments work best for male pattern baldness.

Finasteride (Propecia) blocks the production of testosterone and can be effective. However, men with an enlarged prostate should be cautious. This medication lowers PSA readings, which are a sign of prostate inflammation and cancer, but it does not protect against prostate cancer. Furthermore, for men considering finasteride, it is essential to understand that approximately 1.4% may experience sexual dysfunction that could be permanent. Those who experience anxiety and depression while taking SSRIs may face an additional impact on hair loss and sexual dysfunction due to the combination of the antidepressants and finasteride.

Spironolactone, a medication prescribed for high blood pressure, is sometimes also used off-label for male-pattern baldness and, in combination with finasteride, is used for women with sex hormone-related hair loss.

Initially developed as a blood pressure medication, Minoxidil is commonly used alone or in combination with finasteride in oral and topical formulations. Because it lowers blood pressure, monitoring it is crucial to minimize the risk of dizziness and fainting, which could potentially result in accidents.

Thyroid-related hair loss

Both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can cause hair loss, thinning, and brittleness. The primary treatment is hormonal therapy with levothyroxine. Reduced thyroid function affects vitamin D levels in the body, and even regular vitamin D intake can still be insufficient. Vitamin D3, calcium, other vitamins, micronutrients, and topical minoxidil creams such as Rogaine (also marketed as LONITEN) can help.

Alopecia areata

Alopecia areata is an autoimmune disorder where the immune system mistakenly targets hair follicles, resulting in patchy or complete hair loss. This condition can affect both men and women, with an earlier onset associated with more severe symptoms as time progresses. Research indicates that individuals with alopecia areata are more likely to have other inflammatory conditions, including systemic lupus (5.7 times greater risk), atopic dermatitis (4.3x), psoriatic arthritis (2.3x), rheumatoid arthritis (2.1x), and ankylosing spondylitis (1.7x). Notably, there are ten genetic variants, particularly the HLA alleles and pro-inflammatory genes, that are common between alopecia areata and these associated conditions.

The most common reason for hair loss in people with rheumatoid arthritis is reduced thyroid function or lupus due to severe autoimmune skin disease. However, in people with rheumatoid arthritis, hair loss can also be caused by medications such as methotrexate and leflunomide (Arava), and co-occurrence of alopecia is rare.

Some rheumatoid arthritis medications, especially baricitinib and ritlecitinib, have been effective in addressing both conditions. Sulfasalazine is used for multiple autoimmune conditions, including alopecia. Deuruxolitinib (LEQSELVI) is the newest drug explicitly developed and approved for treating severe alopecia areata.

Frontal fibrosing alopecia

Frontal fibrosing alopecia (FFA) is a condition that causes hair loss on the front and sides of your scalp. The precise causes of FFA remain unclear, but autoimmune reactions, genetics, and hormones may play a role. FFA is most common among postmenopausal women. Women with a specific version of the CYP1B1 gene who also took oral contraceptives were more likely to develop FFA. Women who carry a combination of a risk allele in the ERAP1 gene and one of the HLA alleles are at a 5-17 times higher risk of developing FFA. As with alopecia areata, there is a genetic interaction with a predisposition for inflammatory diseases, including HLA-B*27–associated ankylosing spondylarthritis, HLA-A*29–associated birdshot uveitis, HLA-B*51–associated Behcet’s disease, and HLA-C*06:02-associated psoriasis.

Popular weight loss medications like Ozempic may interfere with micronutrient absorption and lead to hair loss. Conversely, Metformin, an antidiabetic medication, has demonstrated the ability to enhance metabolic health and can occasionally reverse hair thinning. It’s possible to use topical metformin (off-label) alongside minoxidil for added effects.

Central centrifugal cicatricial alopecia

Central centrifugal cicatricial alopecia (CCCA) is a type of scarring alopecia characterized by hair loss in the center or crown of the scalp. It is most prevalent in Black women, but it also occurs in men and people of all races. CCCA is an inflammation-driven scarring of tissue surrounding hair follicles. It is also treated with oral or topical metformin (off-label) and minoxidil.

Stress and mood disorders

In some cases, hair loss can be related to mood disorder or severe stress.   Telogen effluvium is excessive hair shedding after severe stress, hormonal changes, or the use of some medications. Trichotillomania (also known as trich, TTM or hair-pulling disorder, is a mental health condition that can lead to patchy bald spots. Once diagnosed, it is treated with therapy and medicine to treat underlying mental health conditions.

Hair loss medication effectiveness, side effects and your DNA

Recent studies demonstrated equal response to topical and oral formulations for treating male pattern baldness and other milder conditions. It’s essential to recognize that many oral medications could pose serious health risks, requiring careful consideration of other existing conditions, medications, and genetic factors when prescribing them. For example, the deuruxolitinib drug label explicitly warns that it cannot be used in people with inherently reduced CYP2C9 function or those taking medications that inhibit the activity of this liver enzyme.

Hair loss drugs, genetic metabolism and interactions

Emotional impacts of hair loss

It is important to recognize that anxiety, adjustment disorder, and various mental health issues can affect individuals with alopecia. Consequently, a thorough approach to managing all symptoms—such as anxiety, depression, and autoimmune diseases—is vital for effective alopecia treatment outcomes.

How to ensure the safety of oral hair loss medication

Step 1: Get a pharmacogenetic test

While many genes have been linked to male-pattern hair loss, alopecia, and contraceptive-induced Frontal Fibrosing Alopecia, it is not practical to test for the inherited risk factors because they do not affect treatment choices. However, testing your DNA to assess how your body processes different medications would be prudent. The deuruxolitinib drug label explicitly requires a DNA test for drug response, also known as pharmacogenetic testing, before prescribing this medication. Pillcheck and other pharmacogenetic tests assess the main liver enzymes responsible for eliminating these drugs from your body. People with greatly reduced or absent CYP2C9 function should avoid deuruxolitinib due to the high risk of drug-induced toxicity.

It’s important to recognize that your ethnic background influences how your body reacts to drugs. People of non-European or mixed heritage should opt for genetic tests that analyze multiple genetic variants to get accurate results. For example, about 6% of people of African descent have a genetic variant called CYP2C9*8, which is rare in other populations. If this variant isn’t included in a test, it can give false negative results and be risky for those considering deuruxolitinib therapy.

Men of Mediterranean and Middle Eastern descent who have G6PD enzyme deficiency should avoid sulfasalazine and other sulfa drugs, as they can lead to hemolytic anemia.

Many of the described hair-loss drugs are metabolized by the CYP3A4 enzyme, which can be affected by genetic variations and medications.

The Pillcheck test covers all these enzymes and provides drug dosing recommendations for medications used to treat autoimmune and mental health conditions, which may be associated with hair loss.

Step 2: Get advice from an expert pharmacist

Taking multiple medications can increase the risk of adverse side effects due to drug interactions. People with reduced deuruxolitinib clearance should avoid NSAIDs, warfarin and other drugs that can block the CYP2C9 liver enzyme. Certain antiviral and antifungal medications can also reduce the effectiveness of ritlecitinib, spironolactone, triamcinolone and other oral medications by induction of the CYP3A4 enzyme.

If you are taking oral medications for hair loss treatment, you should always consult your doctor or pharmacist before starting any new treatments, even ones that do not require a prescription.

Clinical pharmacists with pharmacogenetics experience can help you and your doctor develop a personalized treatment plan matched to your metabolic profile and health needs. Such service helps to ensure the safety and efficacy of long-term hair loss therapy. Pillcheck’s service includes a state-of-the-art pharmacogenetic test and review of your medications by an expert pharmacist.

Summary

• Different types of hair loss have multiple genetic and environmental triggers, requiring expert diagnosis and appropriate therapy selection.
• Hair loss might be one of the more visible symptoms of an underlying disease. People suffering from hair loss are also more likely to have other autoimmune and mental health conditions that require medication therapy to achieve the best results.
• The liver processes most pills. Genetic differences and other drugs that slow down liver enzymes can impact the effectiveness and safety of hair-loss medications.
• It is prudent to test your DNA to assess medication response before starting oral medications to reduce your risk of drug-induced toxicity. Select a pharmacogenetic test that has higher sensitivity to ensure accurate results.
• Pharmacists can advise you and your doctor whether medication or dosage adjustments are recommended.

Selected references

Kincaid CM. et al. Alopecia areata is associated with risk of inflammatory arthritis Journal of the American Academy of Dermatology, Volume 89, Issue 2, 422 – 423

Mostaghimi A at al Immune-Mediated and Psychiatric Comorbidities Among Patients Newly Diagnosed With Alopecia Areata JAMA Dermatol. 2024; 160(9):945-952. 10.1001/jamadermatol.2024.2404

Betz  RC et al.  Genome-wide meta-analysis in alopecia areata resolves HLA associations and reveals two new susceptibility loci.   Nat Commun. 2015;6:5966. doi:10.1038/ncomms6966

Basmanav FB et al., Clinical Implications of Genetic Discoveries on Frontal Fibrosing Alopecia JAMA Dermatol. Published online February 12, 2025. doi:10.1001/jamadermatol.2024.6433

Rayinda T et al., Epistasis of ERAP1 With 4 Major Histocompatibility Complex Class I Alleles in Frontal Fibrosing Alopecia A Genome-Wide Association Study Meta-Analysis JAMA Dermatol. Published online February 12, 2025. doi:10.1001/jamadermatol.2024.6434