What Medications Cause Hair Loss? A Comprehensive Guide to Drug-Induced Alopecia

October 13, 2025 •

4 min read

Approximately 11% of patients on the common anticonvulsant valproic acid experience alopecia, highlighting how many widely-used therapies can cause this distressing side effect. Understanding what medications cause hair loss is crucial for patients and healthcare providers to effectively manage and mitigate this adverse reaction.

Quick Summary

Many common medications, including chemotherapy agents, hormonal therapies, and anticoagulants, can trigger temporary or persistent hair loss by disrupting the natural hair growth cycle. Recognizing the causative drug is the first step toward effective management, which often involves adjusting or discontinuing the medication under medical guidance.

Key Points

Diverse Culprits: Many different types of medications, not just chemotherapy drugs, can cause hair loss, including anticoagulants, antidepressants, and hormonal therapies.
Two Primary Mechanisms: The main types of drug-induced hair loss are rapid anagen effluvium (common with chemo) and delayed telogen effluvium (associated with many other drugs).
Variable Onset: Hair loss timing varies based on the mechanism; anagen effluvium occurs within weeks, while telogen effluvium typically appears 2–4 months after starting a medication.
Medication Adjustment: The most effective management strategy is often to discontinue or adjust the dosage of the causative medication under a doctor's supervision.
Usually Reversible: Most cases of drug-induced hair loss are temporary and resolve once the problematic drug is stopped, though full recovery can take several months.
Managing Hair Loss: Coping strategies include gentle hair care, using specific topical treatments like minoxidil, and exploring options like scalp cooling during chemotherapy.
Doctor's Consultation: It is essential to consult a healthcare provider before making any changes to your medication regimen.

Understanding the Hair Growth Cycle and Drug-Induced Alopecia

The human hair growth cycle consists of four distinct phases: anagen (growth), catagen (transition), telogen (resting), and exogen (shedding). Most scalp hairs are in the anagen phase at any given time, which typically lasts for several years. Drug-induced hair loss, or alopecia, occurs when a medication interferes with this cycle, leading to excessive or premature shedding.

The two most common mechanisms for drug-induced alopecia are:

Anagen Effluvium: This type of hair loss results from a sudden cessation of cell division in the hair matrix during the active growth phase (anagen). It is most notoriously associated with chemotherapy, which targets and damages rapidly dividing cells throughout the body, including those in hair follicles. Hair loss from anagen effluvium is typically rapid, severe, and occurs within weeks of starting the medication.
Telogen Effluvium: A more common form, this involves the premature shifting of a large number of hair follicles from the growth phase into the resting phase (telogen). This causes diffuse hair shedding that typically becomes noticeable two to four months after starting the offending drug. A vast array of medications can trigger telogen effluvium, which is often dose-dependent and typically reversible.

Major Classes of Medications Linked to Hair Loss

Drug-induced hair loss is not limited to chemotherapy but spans a wide range of medication categories. Awareness of these potential side effects is key to early detection and management.

Chemotherapy Drugs

These are the most well-known culprits, causing anagen effluvium due to their cytotoxic effects on rapidly dividing hair follicle cells. The severity of hair loss depends on the specific drugs, dosage, and delivery method.

Common examples: Doxorubicin, cyclophosphamide, paclitaxel, and docetaxel.

Anticoagulants (Blood Thinners)

Both traditional and modern anticoagulants have been linked to telogen effluvium.

Traditional: Heparin and warfarin.
Newer DOACs: Rivaroxaban (Xarelto) and dabigatran (Pradaxa).

Antidepressants and Mood Stabilizers

Many psychiatric medications, including some of the most commonly prescribed antidepressants, can cause hair shedding.

SSRIs: Sertraline (Zoloft), paroxetine (Paxil), fluoxetine (Prozac).
Mood Stabilizers: Lithium and valproic acid (Depakote).

Hormonal Therapies

Medications that alter hormone levels can trigger or worsen hair loss by impacting the hair cycle.

HRT: Hormone replacement therapy, containing estrogen and progesterone, can cause shedding, particularly during initiation or cessation.
Contraceptives: Birth control pills can induce telogen effluvium due to hormonal shifts.
Androgens: Testosterone replacement therapy and anabolic steroids are known to cause hair loss in men.

Retinoids (Vitamin A Derivatives)

High doses of oral vitamin A and prescription retinoids affect cell growth and differentiation in hair follicles, leading to telogen effluvium.

Common examples: Isotretinoin (Accutane) for acne and acitretin for psoriasis.

Cardiovascular Medications

Several types of drugs for heart and blood pressure conditions have been implicated in hair loss, though it is less common.

Beta-blockers: Propranolol, atenolol, and metoprolol.
ACE inhibitors: Lisinopril and captopril.
Cholesterol-lowering drugs: Statins like atorvastatin (Lipitor).

Other Drug Categories

Immunosuppressants: Medications like methotrexate.
Weight loss drugs: Including semaglutide (Wegovy).
NSAIDs: Such as naproxen.
Antifungals: Fluconazole.

How Different Medications Impact the Hair Cycle

The table below outlines the primary mechanisms and typical timelines for medication-induced alopecia, highlighting the varied effects drugs have on the hair growth cycle.


Drug Category	Primary Mechanism	Typical Onset	Reversibility
Chemotherapy	Anagen Effluvium (damage to active follicles)	Days to weeks	Yes, but regrowth can take months and texture may change
Anticoagulants	Telogen Effluvium (premature resting phase)	2–4 months	Yes, usually resolves after discontinuation
Antidepressants	Telogen Effluvium (premature resting phase)	Weeks to months	Yes, often resolves after discontinuation or dose change
Hormonal Therapies	Telogen Effluvium (triggered by hormonal shift)	Weeks to months	Yes, after stabilizing hormones or discontinuing
Retinoids	Telogen Effluvium (affects cell growth in follicles)	2–4 months	Yes, typically resolves after discontinuation
Beta-blockers	Telogen Effluvium (potential impact on blood flow or cycle)	2–4 months	Yes, resolves after discontinuation

Managing and Coping with Medication-Induced Hair Loss

If you suspect that a medication is causing hair loss, it is crucial to consult your healthcare provider. Never stop or adjust a medication without medical supervision, as it could have serious health consequences. Your doctor can help determine if the medication is the likely cause and explore management strategies.

Possible management approaches include:

Consulting your doctor: Discussing alternative medications, dose reduction, or other treatment options.
Scalp cooling (for chemo): Wearing a 'cold cap' during chemotherapy can help constrict blood vessels in the scalp, reducing the amount of medication reaching the hair follicles.
Topical minoxidil: This over-the-counter treatment can help stimulate hair growth and may be recommended by a dermatologist.
Low-level laser therapy (LLLT): These devices use light to stimulate hair follicles and promote growth.
Gentle hair care: Avoid harsh chemical treatments, excessive heat styling, and tight hairstyles that put stress on hair roots. Use mild shampoos and a soft brush.
Nutritional support: Maintaining a balanced diet rich in vitamins and minerals is important for overall hair health.
Cosmetic solutions: Wigs, scarves, and other headwear can help manage the appearance of hair loss and protect the scalp from the sun.

Conclusion

Medication-induced alopecia is a potential side effect for a wide variety of drugs, with the most severe cases typically associated with chemotherapy. However, many common medications, from anticoagulants to antidepressants, can also cause hair shedding, usually through the slower-onset telogen effluvium mechanism. The good news is that most drug-induced hair loss is reversible once the causative medication is identified and addressed under a doctor's guidance. Recognizing the symptoms, consulting a healthcare professional, and exploring available management strategies can help patients cope with and overcome this challenging side effect. For further information, the American Academy of Dermatology provides valuable resources on hair loss and its causes.

Comparison of Alopecia Mechanisms and Drug Associations


Feature	Anagen Effluvium	Telogen Effluvium
Onset	Rapid; within weeks	Delayed; 2–4 months
Speed	Often rapid and severe	Slower, more gradual shedding
Cause	Damage to actively growing hair follicles	Premature shift of hair to resting phase
Primary Drug Type	Chemotherapy	Wide range of drugs (anticoagulants, antidepressants, etc.)
Reversibility	Yes, but can take time for full regrowth	Yes, usually resolves faster once drug is stopped

Frequently Asked Questions

Chemotherapy drugs are the most known cause of severe, rapid hair loss (anagen effluvium). However, many others are linked to more gradual shedding (telogen effluvium), including anticoagulants like heparin and warfarin, antidepressants like SSRIs and lithium, and hormonal therapies.

No, most cases of drug-induced hair loss are reversible. Once the causative medication is discontinued or its dose is adjusted under medical supervision, hair growth typically resumes within several months.

The timeline depends on the mechanism. With anagen effluvium (e.g., chemotherapy), hair loss can start within days to weeks. For telogen effluvium, the shedding usually becomes noticeable 2–4 months after starting the medication.

Consult your prescribing doctor immediately. Do not stop taking your medication on your own, as this can have serious health consequences. Your doctor can help confirm the link and discuss safe alternatives or dose changes.

Yes, some blood pressure medications, particularly beta-blockers and ACE inhibitors, have been associated with hair loss, usually via telogen effluvium.

Yes, isotretinoin, a retinoid derived from vitamin A used for severe acne, can cause hair loss. This typically presents as telogen effluvium and resolves after the medication is stopped.

Treatment involves addressing the root cause by adjusting the medication. For chemotherapy-induced hair loss, scalp cooling is an option. Other treatments like topical minoxidil and low-level laser therapy may also help stimulate regrowth.

Hormonal contraceptives can alter hormone levels, triggering telogen effluvium, where hair follicles prematurely enter the resting and shedding phase. This is more likely in individuals with a genetic predisposition to hair loss.