Glossary
Hair loss and medication glossary
The words you meet in leaflets, guides and consultations, defined in plain English with the UK source behind each one. The second section covers phrases common in hair loss marketing, each read against the actual MHRA, ASA or GPhC rule.
Medical terms
5-alpha-reductase (types 1 and 2)
5-alpha-reductase is a family of enzymes that convert testosterone into the more potent androgen DHT; hair follicles contain the type 2 enzyme, which is the one...
Read definition →Androgenetic alopecia (pattern hair loss)
Androgenetic alopecia is the medical name for male and female pattern hair loss: gradual, usually inherited thinning in a recognisable pattern, linked to hormon...
Read definition →Dihydrotestosterone (DHT)
Dihydrotestosterone (DHT) is a hormone the body makes from testosterone using the 5-alpha-reductase enzymes, and in people with an inherited sensitivity it grad...
Read definition →Follicular miniaturisation
Miniaturisation is the gradual shrinking of a hair follicle so that each new hair it grows is thinner, shorter and lighter than the last, and it is the hallmark...
Read definition →Hair growth cycle (anagen, catagen, telogen, exogen)
Each scalp hair follicle cycles on its own through a long growth phase (anagen), a short transition (catagen), a resting phase (telogen) and shedding (exogen), ...
Read definition →Half-life (drug half-life)
A medicine's half-life is the time it takes for the amount of the drug in the blood to fall by half, which shapes how long the medicine stays in the body after ...
Read definition →Hamilton-Norwood scale
The Hamilton-Norwood scale is the most widely used way to describe the stage of male pattern hair loss, running from Type I (little or no recession of the hairl...
Read definition →Hypertrichosis (excess hair growth)
Hypertrichosis is hair growth beyond what is normal for a person's age, sex or ethnicity, or for that part of the body, and it is a recognised side effect of mi...
Read definition →Ludwig and Sinclair scales (female pattern hair loss)
The Ludwig and Sinclair scales grade female pattern hair loss, which usually thins the crown while keeping the front hairline: Ludwig uses three grades and Sinc...
Read definition →MHRA Yellow Card scheme
The Yellow Card scheme is the MHRA's system for collecting reports of suspected side effects and other safety problems with medicines and healthcare products, a...
Read definition →Off-label prescribing
Off-label prescribing means a doctor prescribes a licensed medicine outside the terms of its UK licence, for example for a different condition, dose or route, w...
Read definition →Post-finasteride syndrome (PFS)
Post-finasteride syndrome is a term used by patients and researchers for sexual, psychological and physical symptoms that some people report persisting after th...
Read definition →Prescription-only medicine (POM)
A prescription-only medicine (POM) is a medicine that, under UK law, can only be sold or supplied against a prescription from an appropriate practitioner, and t...
Read definition →SmPC and PIL (Summary of Product Characteristics and Patient Information Leaflet)
The SmPC is the official, regulator-approved description of a licensed medicine and the conditions of its use, written for healthcare professionals; the PIL is ...
Read definition →Marketing claims, read against the rules
Compounded medicine (compounded unlicensed special)
A "compounded" medicine in the UK is one prepared by a registered pharmacy to a prescriber's specification for an individual patient. Compounded medicines are n...
Read definition →"Clinically proven"
"Clinically proven" has no formal definition under UK MHRA or ASA rules. In regulatory usage "clinical" means studied in humans, and work in animals or cell cul...
Read definition →"Doctor-formulated" / "developed by doctors"
"Doctor-formulated" has no UK regulatory definition. It signals that a clinician was involved in formulation but does not constitute evidence of efficacy, MHRA ...
Read definition →"No consultation needed"
In UK medicines law, prescription-only medicines (POMs) including finasteride, dutasteride and oral minoxidil require a prescribing clinician's assessment befor...
Read definition →"FDA approved" vs "MHRA licensed"
The US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA) are SEPARATE regulators. An "FDA approved" statu...
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