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Hair Loss Due to Health Issues and Medication Explained

Learn more about drug-induced hair loss and the health conditions that could be contributing to your hair thinning. Click the link to read more.

There are many different types of hair loss, as well as a number of hair loss causes. In many cases, hair loss is hereditary, but drug-induced hair loss or hair loss linked to a medical condition is another common cause.

Though hair loss as a side effect of medication or health conditions can be rare (depending on the condition), it's important for anyone experiencing hair loss to consider all causes - especially if you have a health condition and are taking prescription drugs.

In most cases, drug-induced hair loss is temporary and can be reversed. Consulting your doctor or dermatologist will help you understand the causes and your treatment options.

Let's explore which medications can cause hair loss and why.

How Does Medication Cause Hair Loss? The Hair Growth Cycle

Certain medications and health conditions can cause hair loss by interfering with the regular hair growth cycle, which comprises:

  • The anagen (growing) phase

    . This is the first and longest phase of the hair growth cycle, lasting 3-5 years or as long as seven years for some people.

  • The catagen (transition) phase.


    This phase usually lasts no longer than two weeks and is when hair growth slows as the hair follicles begin to shrink and hair detaches.

  • The telogen (resting) phase.


    During this phase, which lasts approximately three months, new hairs begin to form in the hair follicles.

  • The exogen (shedding) phase.

    This is when hair strands begin to fall out following the resting stage, and new hairs start to grow. It's common for this phase to last 2-5 months.

When diseases or drugs interfere with the scalp hair growth cycle, two types of hair loss can occur:

Telogen Effluvium Hair Loss

The most common type of hair loss caused by medication, telogen effluvium is a type of diffuse alopecia that presents itself 2-4 months after you start taking medication. It works by causing the hair follicles to go into the telogen phase too early, meaning hair fall happens more rapidly. Those experiencing this type of hair loss tend to lose 30% to 70% more than the usual 100 hairs per day.

Anagen Effluvium Hair Loss

This type of hair loss happens during the anagen phase of the cycle when hairs are growing and tends to occur fairly quickly after you start taking medication. It works by preventing the cells that produce new hairs from dividing correctly. Anagen effluvium is most common for those with cancer who are being treated with chemotherapy drugs. Hair loss happens quickly and can cause complete or partial hair loss on the head, eyebrows, eyelashes, and other areas of the body. The type and severity of hair loss you may experience depends on your health condition, the type of drug you're taking, how sensitive you are to the medication, and the dosage you're administered.

Loss of Hair Due to a Medical Condition

In general, a healthy diet, a good lifestyle and an effective hair care regime are advised. This will keep your hair and scalp in optimal condition, to avoid any potential diagnosis that could cause hair loss or hair thinning. Of course, it's possible to develop health conditions, even if you have a well-balanced, healthy lifestyle. Hair loss can be caused by the following conditions:

  • Dramatic weight loss. Crash dieting, restrictive diets, low-protein diets, and weight loss surgery commonly result in nutrient deficiency and rapid weight loss, which can cause temporary hair loss. Getting back on track with a balanced diet will help to restore important nutrients, encouraging weight gain and hair regrowth.

  • Chronic stress. Telogen effluvium, alopecia areata, and trichotillomania (also known as a hair-pulling disorder where you get an urge to pull out your hair) are all forms of hair loss associated with high-stress levels.

  • Physical trauma like surgery or chronic illness. Temporary hair loss can occur when your body and mind go through stressful situations like surgery. Why? Your body needs certain nutrients in order to grow. A stressful event can cause these nutrients to be diverted away from vital organs.

  • Menopause and pregnancy. Though aging can be the primary cause of hair loss or thinning in women, hormonal changes during menopause could be the culprit. Temporary hair loss due to hormones can also be a reality for pregnant women.

  • Thyroid disorders. Severe cases of hypothyroidism and hyperthyroidism can lead to diffuse hair loss (or telogen effluvium). Treatment of the thyroid condition will help with regrowth, but this usually takes several months to occur.

  • Anaemia. Being deficient in iron means your body can't produce hemoglobin in your blood, which in turn prevents oxygen from being carried to the cells that stimulate hair growth. As a result, you may experience hair loss or find your hair won't grow past a certain length.

  • Autoimmune diseases. The most common autoimmune disease that causes hair loss is alopecia areata, which occurs when your immune system attacks your hair follicles, causing small bald patches or larger areas of hair loss. Lupus, Crohn's disease, and other autoimmune conditions have also been linked to hair loss.

  • Polycystic ovary syndrome (PCOS). PCOS can increase the production of sex hormones (androgens) which can cause more masculine features to develop, including excess hair on the face and chest. It can also cause thinning on your head and near the front of your scalp — this is known as androgenetic alopecia or female pattern hair loss. Though it cannot grow back on its own, treatments may help to stimulate the growth of new hair.

  • Skin conditions. Skin conditions like psoriasis and seborrheic dermatitis directly affect the scalp, causing itchy, red, scaly skin which can lead to temporary hair loss, especially if you're prone to scratching.

Medications That Can Cause Hair Loss

All medications come with possible side effects - and hair loss can be one of them. Anti-inflammatory drugs, blood-pressure medications, mood stabilizers, and cholesterol-lowering drugs are all widely used medications that list hair loss and thinning as potential side effects. Other examples include:

  • Anticoagulants. Also known as blood thinners or anti-clotting drugs, anticoagulants like heparin and warfarin can cause hair loss after you start taking them.

  • Antibiotics. Taking antibiotics can impact the way your body uses hemoglobin and vitamin B (both vital for hair growth), which could lead to temporary hair loss.

  • Cancer treatments. Chemotherapy medications for breast cancer and other common forms of cancer are known to cause anagen effluvium for a period of time. How? As well as destroying cancer cells, chemotherapy can attack other rapid-growth cells, like your roots.

  • Vitamin A. Even though vitamin A is beneficial for hair, too much can overstimulate the hair follicles, which causes hair to grow faster and fall out more quickly.

  • Medications for severe acne. Isotretinoin, a drug used to treat severe cases of acne, has been linked to temporary hair loss and continued bouts of hair thinning post-treatment. If you are taking this medication and noticing hair thinning, consider talking to your doctor to adjust your dosage.

  • Oral contraceptives. Birth control pills and other types of hormonal contraceptives, like the implant, can cause hair loss due to a hormonal imbalance. This is more likely to happen if you are particularly sensitive to hormones or have genetic qualities that make you more prone to hair loss.

Treatments for Drug-Induced Hair Loss

If you're concerned about hair loss and you think it could be related to a medication you're taking or a health condition, it's a good idea to speak to a doctor or dermatologist to determine the direct causes and what treatments are available to you. Remember, in most cases, hair loss and thinning of this nature are temporary. Still, we understand it can be damaging to your self-esteem, but there are hair care products and lifestyle changes you can try to help stimulate hair growth and keep your scalp healthy - including:

  • Maintaining a balanced diet - Hair feeds off the minerals and nutrients from the food you eat, so it's always a good idea to include plenty of vitamins and hair-friendly nutrients in your diet, like vitamin C, omega-3, zinc, and iron.

  • Scalp massaging and exfoliation - Regular scalp massages can help improve blood flow and stimulate hair growth. You can also try Nioxin's Scalp Recovery Purifying Exfoliator or Scalp Dermabrasion Treatment to refresh your scalp and remove product build-up.

  • A fool-proof hair care routine - Nioxin's 3-part System Kits for thinning hair include a cleansing shampoo, a moisturizing conditioner, and a leave-in scalp treatment. Available in different types, they help to lay the foundation for thicker, fuller-looking hair.

Find out which of our 3-part System Kits is right for you, and browse all of our hair care and hair styling products - to start your journey to fuller-looking hair and a more confident you.


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