Quick answer

Some medicines can cause hair loss, most often a temporary shedding called telogen effluvium that usually starts two to three months after a new medicine is started and usually recovers without treatment. Medicines linked to hair loss include chemotherapy, anticoagulants such as warfarin, some epilepsy medicines such as sodium valproate, some antidepressants, some blood pressure tablets, retinoids, hormonal treatments and weight-loss injections such as semaglutide. If you think a medicine is affecting your hair, never stop or change it yourself: speak to your GP, pharmacist or the doctor who prescribed it first.

Can medication really cause hair loss?

Yes. Doctors call it drug-induced hair loss, or drug-induced alopecia. It is a recognised side effect of a number of common medicines, not just chemotherapy.

It can be very upsetting, especially if you are already taking the medicine for something serious. The reassuring part is that in most cases the hair loss is temporary and the hair follicles are not permanently damaged.

If you started a new medicine, changed your dose, or came off a hormone treatment in the last few months and you are now seeing more hair in the shower or on your brush, the medicine is one possible reason. It is not the only one, so it is worth getting it checked properly rather than guessing.

How do medicines cause hair loss?

Each hair on your scalp goes through a cycle: a long growing phase, a short transition, then a resting phase before the hair falls out and a new one starts. Medicines can upset this cycle in two main ways.

Telogen effluvium (the common one). The medicine pushes more hairs than normal into the resting phase at the same time. A few months later they fall out together, so you notice diffuse shedding all over the scalp rather than bald patches. The British Association of Dermatologists (BAD) says telogen effluvium can occur around three months after a trigger, and that the shedding phase lasts between three and six months. A 2020 review in the journal Cureus puts the usual gap at two to three months after the trigger.

Anagen effluvium (mostly chemotherapy). Some medicines, mainly chemotherapy, affect hairs while they are still actively growing. The hair loss starts much sooner and can be heavier. Macmillan Cancer Support says hair loss from chemotherapy usually starts about two to three weeks after the first session.

Because telogen effluvium shows up months after the medicine was started, people often do not connect the two. Thinking back to what changed around three months before the shedding began is often the most useful clue.

Which medicines can cause hair loss?

The list below covers the groups most often linked to hair loss in the sources we used. Not everyone who takes these medicines will lose hair, and for most of them hair loss is an uncommon side effect.

Chemotherapy

Chemotherapy drugs target fast-dividing cells, and hair follicles are among the fastest-dividing cells in the body. Macmillan says not all chemotherapy drugs cause hair loss, and that not losing your hair does not mean the treatment is not working. Hair on the eyebrows, eyelashes, beard and body can also be affected. Macmillan says these changes are almost always temporary and most people find their hair starts to grow back after treatment is over, though it may grow back differently. Very rarely, some chemotherapy drugs can permanently damage hair follicles. Scalp cooling, offered in some hospitals, may reduce hair loss with some chemotherapy drugs: ask your cancer team.

Anticoagulants (blood thinners)

Anticoagulants are among the medicines best known for causing telogen effluvium. NHS inform (Scotland's NHS health information service) lists skin rashes and hair loss as common side effects of warfarin. Heparin is also named in the medical literature. A 2021 case report in BMJ Case Reports describes hair loss as a rare but clinically important side effect of all anticoagulants, including the newer tablets, and describes one patient whose hair recovered after their doctor switched them to a different anticoagulant.

Blood thinners are usually prescribed to prevent dangerous clots, so stopping one without advice can be very risky. If you are worried about hair loss on an anticoagulant, raise it with the doctor or anticoagulation clinic that manages it.

Epilepsy medicines

The NHS lists thinning hair, or changes to the colour or texture of hair, among the common side effects of sodium valproate, and suggests asking your doctor whether a lower dose is possible if it bothers you. Other anticonvulsant medicines are also named as possible triggers of telogen effluvium.

Antidepressants

Antidepressants are among the medicine groups named as possible causes of telogen effluvium. The NHS is clear that you should not stop taking an antidepressant suddenly or without talking to your doctor first, because stopping needs to be done gradually to reduce withdrawal symptoms. If hair loss is bothering you, your doctor can look at whether a change in dose or medicine is right for you.

Blood pressure and heart medicines

Beta-blockers and ACE inhibitors, two widely used groups of blood pressure medicines, are listed among the medicine causes of telogen effluvium in the 2020 Cureus review.

Retinoids

Retinoids, a group of vitamin A based medicines used for conditions such as severe acne and psoriasis, are also listed as possible triggers of telogen effluvium.

Hormonal medicines and contraception

Hormones have a strong effect on the hair cycle. The BAD lists starting new medications or stopping a hormone treatment, such as coming off the contraceptive pill, among the triggers of telogen effluvium. Androgens (male-type hormones) and oral contraceptive pills are also named in the medical literature.

Weight-loss injections

The NHS lists hair loss as a common side effect of semaglutide, which is used for type 2 diabetes and to treat obesity. It is not yet fully clear why. A 2025 letter in the Journal of Cosmetic Dermatology suggests rapid weight loss and possible nutritional shortfalls may play a part, while noting that definitive proof is still lacking. The BAD separately lists significant weight loss as a trigger for telogen effluvium, whatever the cause.

What should I do if I think my medicine is causing hair loss?

Do not stop taking a prescribed medicine, or change the dose, without speaking to your doctor first. Many of the medicines above treat serious conditions such as blood clots, epilepsy, depression and high blood pressure. Stopping them suddenly can be dangerous, and your hair will usually recover once the cause is sorted out properly.

Instead:

• Speak to your GP, your pharmacist or the doctor who prescribed the medicine. Tell them when the shedding started and when you began, stopped or changed any medicine. They can tell you whether hair loss is a known side effect and whether a different dose or medicine might suit you.
• Keep a simple note. Write down the dates you started each medicine and when you noticed the shedding. Photos of your parting or hairline taken a few weeks apart in the same light help too.
• Report it if you want to. In the UK, anyone can report a suspected side effect to the MHRA's Yellow Card scheme, which helps the regulator spot patterns.
• Get urgent help for other symptoms. Hair loss on its own is not an emergency, but if you have other new symptoms after starting a medicine, follow the advice in the patient leaflet or contact NHS 111.

Will my hair grow back?

In most cases, yes. The BAD says telogen effluvium usually gets completely better without any treatment, and that it is very unusual for it to cause thinning severe enough to need a wig. It can take many months for your hair to get back to its normal volume and thickness, because new hairs grow at roughly the normal slow rate. The 2020 Cureus review reports that acute telogen effluvium goes into remission in around 95% of cases.

For chemotherapy, Macmillan says most people find their hair starts to grow back after treatment ends, though its colour or texture may be different at first, and permanent loss is very rare.

Could it be something else?

It could. The BAD notes that for about 1 in 3 people with telogen effluvium no cause is ever found. Other common triggers include illness, surgery, childbirth, stress and significant weight loss, and the NHS also lists iron deficiency among the causes of temporary hair loss.

Medicine-related shedding can also happen at the same time as male or female pattern hair loss, which is genetic and gradual. Sometimes a period of shedding simply makes someone notice thinning that was already developing. If your hair is not recovering, or you are seeing a receding hairline or thinning crown rather than even shedding all over, it is worth having it assessed. Our guides to the Norwood scale and DHT and hair loss explain how pattern hair loss differs.

Is a hair transplant an option for medicine-related hair loss?

Usually not, and a good clinic should tell you so. The NHS says a hair transplant is suitable for permanent baldness of the type that runs in families, and not usually for other types of hair loss. Temporary shedding from a medicine normally recovers on its own, so surgery would not be the right answer.

A transplant only becomes relevant if the underlying problem turns out to be permanent pattern hair loss. At FUE Clinics, a trichologist consultation can help you understand what type of hair loss you have before you think about any treatment. If pattern hair loss is confirmed and you want to explore surgery, you can read about FUE hair transplants and hair transplants for women. Consultations are free, surgery is carried out in the UK, and you can call us on 0330 363 0001 or contact us online.

Frequently asked questions

How long after starting a medicine does hair loss begin? With telogen effluvium, the most common type, shedding usually starts around two to three months after the medicine was started. Hair loss from chemotherapy starts sooner, usually about two to three weeks after the first session.

Should I stop my medicine if my hair is falling out? No. Never stop or change a prescribed medicine without speaking to your doctor first, as stopping suddenly can be dangerous. Your GP, pharmacist or prescriber can advise whether a change is appropriate.

Is hair loss from medication permanent? Usually not. Telogen effluvium usually gets completely better without treatment, although it can take many months for the hair to return to its normal thickness. Permanent hair loss from chemotherapy is very rare.

Can weight-loss injections cause hair loss? The NHS lists hair loss as a common side effect of semaglutide. Rapid weight loss is itself a known trigger for temporary shedding, so speak to your prescriber if you notice it.

Does the contraceptive pill cause hair loss? Starting a new hormone medicine or coming off the contraceptive pill is a recognised trigger for telogen effluvium, according to the British Association of Dermatologists. It is usually temporary.

Who should I see about hair loss from a medicine? Start with your GP, pharmacist or the doctor who prescribed it. If the hair does not recover, or you think you may also have pattern hair loss, a trichologist or dermatologist can assess it.

Sources

• NHS, Hair loss: https://www.nhs.uk/conditions/hair-loss/
• NHS, Hair transplant: https://www.nhs.uk/tests-and-treatments/cosmetic-procedures/cosmetic-surgery/hair-transplant/
• NHS, Side effects of sodium valproate: https://www.nhs.uk/medicines/sodium-valproate/side-effects-of-sodium-valproate/
• NHS, Semaglutide: https://www.nhs.uk/medicines/semaglutide/
• NHS, Antidepressants, considerations (stopping): https://www.nhs.uk/mental-health/talking-therapies-medicine-treatments/medicines-and-psychiatry/antidepressants/considerations/
• NHS inform, Warfarin: https://www.nhsinform.scot/tests-and-treatments/medicines-and-medical-aids/types-of-medicine/warfarin/
• British Association of Dermatologists, Telogen effluvium (BAD Patient Hub): https://www.skinhealthinfo.org.uk/condition/telogen-effluvium/
• Macmillan Cancer Support, Hair loss during treatment: https://www.macmillan.org.uk/cancer-information-and-support/impacts-of-cancer/hair-loss/hair-loss-during-treatment
• Macmillan Cancer Support, Hair loss: https://www.macmillan.org.uk/cancer-information-and-support/impacts-of-cancer/hair-loss
• MHRA, Yellow Card scheme: https://yellowcard.mhra.gov.uk/
• Asghar F, Shamim N, Farooque U, Sheikh H, Aqeel R. Telogen Effluvium: A Review of the Literature. Cureus, 2020: https://pmc.ncbi.nlm.nih.gov/articles/PMC7320655/
• Hull KL, Gooding R, Burton JO. Resolution of warfarin-induced alopecia with conversion to apixaban. BMJ Case Reports, 2021: https://pmc.ncbi.nlm.nih.gov/articles/PMC7929877/
• Haykal D. Alopecia and Semaglutide: Connecting the Dots for Patient Safety. Journal of Cosmetic Dermatology, 2025: https://pmc.ncbi.nlm.nih.gov/articles/PMC11909624/