This is the topic where cosmetic advice is least useful and most confidently given. The honest position: significant hair loss almost always has an internal cause, and no shampoo addresses it.

What is normal

50 to 100 hairs a day. They collect visibly in a brush, in the shower drain and on a pillow, which makes normal shedding look alarming.

Shedding is also seasonal for many people — autumn is commonly heavier.

What is not normal

  • Noticeably more than usual, sustained over weeks
  • A widening parting
  • A ponytail that has visibly thinned
  • Hair coming out in clumps
  • Patches of loss
  • A receding hairline
  • Visible scalp where there was none

Any of these is worth investigating rather than treating with products.

The common causes

  • Iron deficiency, one of the most frequent and easily tested
  • Thyroid conditions
  • Hormonal change — pregnancy, postpartum, menopause, stopping contraception
  • Stress or illness, typically showing up two to three months after the event, which is why the connection gets missed
  • Rapid weight loss or restrictive dieting
  • Some medications
  • Androgenetic hair loss, the hereditary pattern kind, which is progressive and most treatable when caught early
  • Traction from tight styles worn constantly

Notice that none of these are shampoo problems.

What to do

See a doctor. Blood tests for iron, ferritin, thyroid and vitamin D cover most of the treatable causes. This is the single most useful step, and delaying it in favour of trying products is the most common mistake.

Do not wait months. Some causes respond well to early treatment and poorly to late treatment. Hereditary loss in particular is far easier to slow than to reverse.

What products can honestly do

  • Keep the scalp healthy, which supports the hair you have
  • Reduce breakage, so hair does not snap and appear to be falling out
  • Make hair look fuller
  • Nothing more

Breakage and loss are different: breakage leaves short broken pieces, loss leaves whole hairs with a small white bulb at the end. Look at what is in your brush — if the hairs are short fragments, that is a damage problem, and it is fixable with gentler handling.

What to be sceptical of

Any product promising regrowth. Any supplement promising it without knowing your blood results. Anything sold with before-and-after photographs.

For gentle scalp care meanwhile, see the shampoo guide.