The Top 8 Causes of Hair Loss and How to Address Each One
Almost all hair loss traces back to eight causes: genetics, hormonal changes, stress, nutrition, medication, medical conditions, scalp problems and physical damage. Each has its own signature and its own fix, which is why identifying yours is the single most useful step you can take. Here are the top eight, ranked roughly by how common they are, with what to do about each and where to read the deep guide.
Key takeaways
- Genetics (pattern loss) is the most common cause, and responds best to early treatment.
- Hormones, stress and nutrition cover most of the rest, and are largely fixable.
- The pattern of your loss (patchy, diffuse, patterned, broken) identifies the cause.
- A GP blood test rules the treatable causes in or out quickly.
- Whatever the cause, gentle care protects the hair you have.
1. Genetics: pattern hair loss (androgenetic alopecia)
The signature: gradual, patterned thinning, receding hairline and crown in men, a widening parting in women, often with family history.
What to do: act early. Licensed treatments (topical minoxidil for both sexes, finasteride for men) work best while follicles are still active, ask a pharmacist or GP. For established loss, transplants are an option, see our FUE vs FUT guide.
2. Hormonal changes
The signature: thinning that tracks a life stage, after childbirth, through the menopause, with PCOS, or alongside a thyroid condition.
What to do: address the hormones with your GP, postpartum shedding self-resolves, thyroid loss reverses with treatment, and menopause and PCOS respond to medical care.
3. Stress and shock (telogen effluvium)
The signature: diffuse shedding all over, arriving 2 to 3 months after major stress, illness, fever or surgery, the classic telogen effluvium pattern (including post-COVID shedding).
What to do: resolve the trigger and wait, it almost always recovers within months. Manage ongoing stress so it does not repeat.
4. Nutrition
The signature: diffuse shedding after crash dieting, or alongside low iron, zinc, B12 or vitamin D.
What to do: a GP blood test, then fix the gap, deficiency-driven loss usually reverses fully. Day to day: protein, iron, zinc and B vitamins, with a supplement like our GrowPro gummies as a top-up alongside a balanced diet.
5. Medication side effects
The signature: shedding that began after starting a new medicine, some blood thinners, antidepressants, beta-blockers and others list hair loss as a side effect.
What to do: never stop a medicine on your own, tell your GP, who can confirm and consider alternatives.
6. Medical conditions
The signature: smooth round patches point to alopecia areata; scaly, itchy patches in children often mean ringworm; other autoimmune conditions can also affect hair.
What to do: a GP or dermatologist promptly, these have specific medical treatments, and early diagnosis matters.
7. Scalp problems
The signature: flaking, itching and irritation alongside shedding, from seborrheic dermatitis, psoriasis or infection.
What to do: treat the scalp condition (a pharmacist can start you off) and the hair usually recovers with it. A gentle everyday wash like our Grow Me shampoo keeps the scalp comfortable between treatments.
8. Physical damage: breakage and traction
The signature: short snapped hairs, split ends, or thinning edges from tight styles, damage masquerading as loss.
What to do: the easiest fix on the list, looser styles, lower heat with a protectant, gentle detangling, and a weekly deep-conditioning mask. See how to reduce hair breakage.
The causes at a glance
| Cause | Pattern | Reversible? |
|---|---|---|
| Genetics | Patterned, gradual | Manageable, best treated early |
| Hormones | Life-stage linked | Often, with medical care |
| Stress/shock | Diffuse, delayed 2-3 months | Yes, usually self-resolves |
| Nutrition | Diffuse | Yes, fix the deficiency |
| Medication | Follows a new prescription | Usually, via your GP |
| Medical conditions | Patches or with other symptoms | Often, with treatment |
| Scalp problems | With flaking/itching | Yes, treat the scalp |
| Damage | Breakage, thinning edges | Yes, gentler care |
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Frequently asked questions
What is the number one cause of hair loss?
Genetic pattern hair loss (androgenetic alopecia), by a distance, in both men and women.
How do I find out what is causing my hair loss?
Read the pattern, look back three months for triggers, and see your GP for a blood test, that combination identifies most causes.
Which causes of hair loss are reversible?
Stress, nutrition, medication, scalp and damage causes usually reverse. Pattern loss is manageable rather than curable, especially treated early.
Can several causes overlap?
Very commonly, for example pattern thinning plus stress shedding plus breakage. Address each and the picture improves faster.
When should hair loss worry me?
Sudden, patchy, severe or persistent loss, or loss with other symptoms, see your GP promptly.
Eight causes, eight fixes, and yours is almost certainly on the list. Work out which with our self-diagnosis guide, then act early with the first-90-days plan.
