Excessive Hair Fall? Discover the Possible Link to Thyroid and Hormonal Imbalances

Medically reviewed by: Dr. Tom Babu, Consultant Diabetologist & Endocrinologist - Written by Riya Yacob - Updated on 29/10/2026

Yes, excessive hair fall can be linked to thyroid and hormonal imbalances. An underactive or overactive thyroid gland changes how hair follicles grow and rest. Shifts in oestrogen, androgens or cortisol can have a similar effect. A blood test, advised by a doctor, shows whether a hormone issue sits behind the shedding. 

Key Takeaways 

● Thyroid hormones help keep hair follicles active, so low or high levels can thin the whole scalp

● Hypothyroidism and hair loss often appear together, as do hyperthyroidism and hair loss

● Hormonal hair loss in women can follow pregnancy, PCOS or menopause

● Hair shed from a hormone issue usually grows back once levels are corrected

● A thyroid profile and a few other blood tests give a clear starting point 

Finding more hair on the pillow, in the shower drain or on your comb is worrying, and the cause is easy to overlook. Many people try a new shampoo or oil first, when the real reason may sit in the bloodstream. This blog explains how excessive hair fall connects with thyroid health and hormones, which signs are worth noting, and what testing involves. 

How Thyroid Hormones Affect Hair Growth

The Normal Hair Cycle

Each strand grows for two to six years, rests for about three months, and then falls out so a new one can begin. Around 90 per cent of scalp hair is usually in the growing phase at any moment. Losing 50 to 100 strands a day is within the usual range.

What Changes When Thyroid Levels Shift

Hair follicle cells carry receptors for thyroid hormone, which means they respond directly to the amount circulating in your blood. When levels move too high or too low, more follicles shift into the resting phase together. Roughly two to three months later, the extra strands fall out. That delay explains why people often struggle to connect a recent change in health with the hair they are losing today. This is the basic pattern behind thyroid and hormonal imbalance hair loss. 

Different Thyroid Hair Loss Conditions 

Thyroid hair loss can follow either of two conditions, and the hair looks a little different in each. 

Hypothyroidism and Hair Loss

In an underactive thyroid, the body makes less hormone than it requires. Hypothyroidism and hair loss go hand in hand because the follicles slow down. Hair becomes dry, coarse and brittle, and it grows slowly. The outer third of the eyebrows may thin as well. Other companions include tiredness, weight gain, feeling cold, dry skin and constipation.

● Hyperthyroidism and Hair Loss

An overactive thyroid speeds everything up. With hyperthyroidism and hair loss, the strands turn fine and soft, and the scalp looks evenly thinner rather than patchy. Weight loss, a fast heartbeat, sweating, shaky hands and restless sleep often come alongside it. 

● Treatment

Treatment for an overactive thyroid can sometimes swing levels too far the other way, and a few other medicines also affect thyroid function. Mentioning every tablet you take helps your doctor read your results properly. 

Thyroid vs Other Hormonal Causes 

Hormonal Imbalance and Hair Fall

Thyroid hormones are only one part of the picture. Hormonal imbalance and hair fall are connected through several other messengers, including oestrogen, progesterone, testosterone and cortisol. 

Hormonal Hair Loss in Women 

Hormonal hair loss in women appears at specific life stages, so timing offers a useful clue. 

• Polycystic Ovary Syndrome

Higher androgen levels can shrink follicles along the central parting. Irregular cycles, acne and unwanted facial hair usually appear with it.

•  Pregnancy and the Months After Delivery

Oestrogen stays high during pregnancy, which keeps more hair on the head. After delivery, it drops, and the hair held back sheds over a few months. Most mothers see this settle by the baby’s first birthday.

• Perimenopause and Menopause 

Falling oestrogen and progesterone leave the hair thinner and slower to grow. Because thyroid conditions are also more common around midlife, doctors usually check both. 

Hair Fall Due to Hormonal Changes in Everyday Life

Hair fall due to hormonal changes can also follow stopping or starting birth control pills, long periods of high stress and rapid weight change. Cortisol, the stress hormone, can push follicles into rest in the same way thyroid shifts do. 

Other Excessive Hair Fall Causes Worth Checking 

A hormone test is one piece of the puzzle. The wider list of excessive hair fall causes includes low iron stores, low vitamin D or B12, a diet short on protein, scalp conditions and certain medicines. Doctors look at these together because they can exist alongside thyroid changes and share similar symptoms. 

Causes of Sudden Hair Fall 

The causes of sudden hair fall usually involve a recent trigger. Common ones are a high fever, major surgery, childbirth, crash dieting or a period of intense emotional strain. Because of the resting-phase delay mentioned earlier, the trigger often happened two to three months before the shedding started. Looking back across that window helps your doctor decide which tests make sense. 

What the Research Says 

Studies back up the connection. A 2023 review of research on thyroid disease and alopecia reported that the share of people with alopecia who also have a thyroid illness ranges from 8% to 28%, depending on the population and the type of hair loss studied. The same review described a study in which antithyroid antibodies were found in 25.7% of people with alopecia compared with 3.3% of healthy people.  

More recently, a 2024 genetic study published in Clinical, Cosmetic and Investigational Dermatology found evidence that hypothyroidism plays a causal role in alopecia areata, while pattern hair loss appeared to follow other routes. 

These figures show that the link is genuine, but thyroid testing is the only way to know your own situation. 

Signs That Point Towards a Hormonal Cause 

Keep an eye out for these combinations:

● Hair thinning across the whole scalp over several weeks

● Changes in energy, weight or body temperature

● Irregular, heavy or missed periods

● Dry skin, brittle nails or a hoarse voice

● Thinning along the outer eyebrows

● Hair loss that began after childbirth, illness or a medicine change 

Noting when each sign began, even roughly, saves time during the appointment. When to See a Doctor and What Tests to Expect 

When to See a Doctor and What Tests to Expect 

Book a visit if shedding continues beyond three months, if you see clear bald patches, or if other symptoms from the list above join in. Your doctor will usually begin with a few questions, a look at your scalp and a gentle pull test. 

Blood tests commonly include: 

• TSH and free T4 to check thyroid function
•  Thyroid antibodies if an autoimmune cause is suspected
•  Ferritin, vitamin D and B12 to check nutritional stores
•  Androgen and other hormone levels when periods are irregular or other signs suggest PCOS 

At Silverline Hospital, we review these results together so the plan covers the whole picture rather than a single number. 

Treatment and Daily Care

When a thyroid condition is the cause, the usual route is a prescribed medicine that brings hormone levels back to a healthy range. Hair typically begins to recover within 3 to 6 months after levels settle, and full regrowth can take a year. For other hormonal causes, treatment depends on the trigger, whether that is managing PCOS, adjusting a medicine or allowing postpartum hair to recover. 

Daily habits support the process: 

• Eat enough protein, iron and zinc through regular meals 
• Use a mild shampoo and wide-toothed comb
• Keep heat styling and tight hairstyles to a minimum
• Build steady sleep and stress management into the week 

Conclusion

Excessive hair fall has many possible origins, and thyroid problems along with other hormonal shifts rank among the most treatable. The pattern of shedding, the timing and any added symptoms give valuable clues. With a simple blood test and a proper review, most people receive a clear explanation and a plan to bring their hair back to its fuller state.