What medications can cause hair thinning?

What Medications Can Cause Hair Thinning?

Hair thinning—or medication hair loss—can affect anyone taking certain drugs. While not everyone on these medications will notice a change, understanding which treatments are most often linked to hair shedding can help you make informed decisions and talk to your doctor about alternatives or solutions.

How Medications Trigger Hair Thinning

Medications typically cause hair loss by disrupting normal hair‐growth cycles. Hair follicles cycle through three phases:

• Anagen (growth): Active hair growth
• Catagen (transition): Growth stops
• Telogen (rest): Hair sheds

Certain drugs force follicles into the telogen phase prematurely (telogen effluvium) or directly damage rapidly dividing cells (anagen effluvium). Trueb (2007) describes how these changes often begin 2–4 months after starting the medication and may resolve several months after stopping it.

Common Medication Classes Linked to Hair Loss

Below is an overview of drug categories most frequently associated with hair thinning. Individual responses vary, and dosage or duration of treatment can influence risk.

• Chemotherapy & Immunosuppressants
  These are among the most potent causes of anagen effluvium.

  • Cyclophosphamide, doxorubicin
  • Methotrexate, 6-mercaptopurine
  • Paclitaxel, vincristine
  • Biologics (some monoclonal antibodies)

• Anticoagulants
  Heparin and warfarin often trigger telogen effluvium after several months.

  • Heparin (unfractionated, low-molecular-weight)
  • Warfarin (Coumadin)

• Lipid-Lowering Agents
  Statins and fibrates can occasionally disrupt hair growth.

  • Atorvastatin, simvastatin
  • Fenofibrate, gemfibrozil

• Beta-Blockers & Cardiovascular Drugs
  Used for hypertension and heart conditions.

  • Propranolol, metoprolol
  • ACE inhibitors (lisinopril) and ARBs (losartan) have been reported rarely.

• Retinoids
  Oral vitamin A derivatives can cause diffuse shedding.

  • Isotretinoin (Accutane)
  • Acitretin, isotretinoin analogs

• Antidepressants & Mood Stabilizers
  Both older and newer agents carry risk.

  • SSRIs: sertraline, paroxetine
  • TCAs: amitriptyline, nortriptyline
  • Lithium (mood stabilizer)
  • Valproate, carbamazepine (antiepileptics)

• Hormonal Therapies
  Shifts in androgen or estrogen balance influence follicle cycling.

  • Levonorgestrel IUD, injectable progestins
  • Hormone-replacement therapy (estrogen/progesterone)
  • Anti-androgens (cyproterone acetate) may improve hair, but spiro- nolactone can cause shedding in some.

• Thyroid Medications
  Overtreatment or rapid correction of thyroid levels can trigger telogen effluvium.

  • Levothyroxine (Synthroid)

• Other Agents

  • NSAIDs (indomethacin, naproxen)
  • Proton pump inhibitors (omeprazole, esomeprazole)
  • Antifungal agents (griseofulvin)
  • Antiretrovirals (zidovudine)

Who’s at Risk?

• People starting high-dose or combination chemotherapy
• Patients on long-term anticoagulation or retinoids
• Those with nutrient deficiencies (iron, zinc), where medication effects are amplified
• Individuals with preexisting hair thinning or hormonal imbalances

Recognizing Medication Hair Loss

Signs to watch for include:

• Widening part or receding hairline
• Excess shedding during brushing or washing
• Generalized thinning across the scalp

If you notice these changes, consider doing a free, online symptom check for Hair loss to gather insights before your doctor’s appointment.

Managing Drug-Induced Hair Thinning

1. Review the Medication List
   Work with your clinician or pharmacist to confirm which drug(s) may be responsible.
2. Assess Timing
   Telogen effluvium often appears 2–4 months after the trigger. Anagen effluvium can start within days to weeks.
3. Consider Alternatives or Dose Adjustments
   • Lowering dose (when safe)
   • Switching to a less hair‐affecting agent
4. Support Hair Health
   • Ensure adequate protein, iron and micronutrients
   • Use gentle hair care (mild shampoo, avoid tight hairstyles)
   • Minoxidil (topical) may help some patients
5. Patience & Monitoring
   Hair regrowth can take 3–6 months after stopping or adjusting the medication.

When to Seek Immediate Medical Advice

While most medication-related hair loss is not dangerous, consult your doctor promptly if you experience:

• Sudden, massive hair loss
• Signs of infection or inflammation on the scalp
• Accompanying symptoms like fever, rapid weight loss, severe fatigue
• Any new, unexplained bleeding or bruising (with anticoagulants)
• Jaundice, confusion, swelling in legs (possible liver issues per D’Amico et al. 2006 and EASL 2018)

These could indicate serious complications requiring urgent care.

Final Thoughts

Medication hair loss can be distressing, but often it’s reversible. If you suspect a drug is causing hair thinning:

• Talk with your prescribing doctor before stopping or changing any treatment
• Discuss alternative therapies or supportive measures
• Use the free symptom check for Hair loss to prepare for your visit

Always seek medical advice for potentially life-threatening or serious concerns. Your healthcare team can help you balance effective treatment with maintaining healthy hair.