Alopecia means hair loss. It is an umbrella term covering several conditions, from gradual hereditary thinning to temporary shedding, autoimmune hair loss and diseases that scar the scalp. Alopecia areata is one particular type, usually associated with smooth bald patches; it is not another name for every form of alopecia.

The right treatment depends on what is happening to your follicles. A receding hairline, sudden handfuls of shed hair and an inflamed bald patch need different assessments. Some hair loss recovers, some needs continuing treatment, and some can become permanent. This guide explains the main differences, what a doctor looks for and which options may be appropriate.

DHT contributes to pattern hair loss by acting on genetically susceptible follicles. It does not cause every type of alopecia, and thinning hair does not automatically mean that your blood DHT level is too high. The response of the follicle matters as well as the hormone itself.

This distinction explains why a blood test cannot tell the whole story and why products sold as “DHT blockers” need careful scrutiny. Some prescription medicines reduce DHT formation; other hair treatments work through different pathways. Understanding the difference helps you ask better questions about benefit, risks and long-term treatment.

A DHT blood test measures a circulating hormone concentration. It does not directly measure how sensitive the follicles on your hairline or crown are to that hormone, and it is not a routine requirement for every person with pattern thinning.

Androgenetic alopecia is progressive pattern hair loss caused by changes in susceptible hair follicles. In men, it commonly affects the temples, frontal hairline and crown. In women, it more often causes thinning over the top of the scalp and a widening parting. Treatment can help preserve hair or improve density, but response varies and benefits usually require continuing treatment.

The first step is to confirm that pattern hair loss explains the change. Sudden patches, marked scalp inflammation or a rapid increase in shedding may indicate another condition, sometimes alongside androgenetic alopecia. Here is how the condition develops, how it is diagnosed and what to consider when choosing treatment.

A receding hairline means that the front boundary of your hair is moving backwards, often most noticeably at the temples. In men, gradual recession commonly forms part of androgenetic alopecia, or male pattern hair loss. An M-shaped hairline alone, however, does not establish the cause or predict how much hair you will lose.

Treatment depends on that cause and on whether follicles are still producing hair. Medicines may slow pattern hair loss and improve growth in some people, while a transplant can redistribute suitable donor hair. Neither approach guarantees a return to a teenage hairline. If the change is sudden, patchy, painful or accompanied by eyebrow loss, arrange a medical assessment before choosing a cosmetic treatment.

This guide explains how to recognise a change, what the stages mean and how to compare realistic options for temple hair loss.

The Norwood scale, also called the Hamilton–Norwood scale, describes common patterns of male hair loss in seven main stages. Lower stages show little or limited recession; higher stages show more extensive loss across the front and crown, with a remaining fringe at the sides and back.

You can use it to understand the pattern visible today and discuss changes with a clinician. It does not predict your future baldness, diagnose every cause of hair loss or calculate a transplant graft count. The stage must be considered alongside your age, medical history, scalp examination and donor supply.

The montage above contains eight numbered panels. The standard Hamilton–Norwood system has seven main stages plus variants; it does not include a standard stage eight.

The hair growth cycle describes how a follicle grows a hair, pauses and releases it before producing another. Its four commonly described stages are anagen, catagen, telogen and exogen. Different follicles follow their own schedules, which is why some daily shedding can happen while overall coverage remains stable.

Understanding the timings helps explain two common concerns: why hair may start shedding months after an illness, and why recovery is not visible immediately after the trigger resolves. It also helps distinguish a shed hair from a broken hair and set realistic expectations after treatment or transplantation.

These are useful biological ranges, not a calendar that predicts the day an individual hair will fall out.