Aesthetic Medicine Glossary — Essential Terms Explained

Last updated: 5 March 2026

Navigating the world of aesthetic medicine can feel overwhelming, particularly when practitioners use specialised terminology. Understanding these terms empowers you to make informed decisions. This glossary, compiled with reference to the BAAPS and the JCCP, covers the most commonly encountered terms.

Treatment Types and Techniques

Botulinum Toxin

A purified protein derived from Clostridium botulinum that temporarily relaxes targeted muscles by blocking acetylcholine release. Licensed UK brands include Botox, Dysport, and Bocouture. Effects last 3-4 months. It is a prescription-only medication (POM) in the UK.

Dermal Fillers

Injectable substances used to restore volume, contour features, and smooth wrinkles. The most common type is hyaluronic acid (HA). Popular brands include Juvederm, Restylane, and Teosyal. Unlike botulinum toxin, fillers are not currently classified as prescription medicines in the UK, though regulatory reform is pending.

Biostimulators

Treatments that stimulate the body’s own collagen production. Examples include poly-L-lactic acid (Sculptra), calcium hydroxylapatite (Radiesse), and polynucleotide-based products (Ameela, Nucleofill). Results develop gradually over weeks to months.

Mesotherapy

Multiple microinjections of vitamins, minerals, amino acids, and hyaluronic acid into the mesodermal layer. Coined by French physician Dr Michel Pistor in 1958.

Microneedling (Collagen Induction Therapy)

Fine needles create controlled micro-injuries, triggering the wound-healing cascade and stimulating collagen and elastin production. Needle depths range from 0.25mm to 2.5mm.

Skin Science Terminology

Collagen

The most abundant protein in the human body. Production declines approximately 1% per year after age 25. There are 28 types; types I, III, and VII are most relevant to skin.

Elastin

Gives skin its ability to stretch and return to shape. Production essentially ceases after puberty, making preservation critical.

Hyaluronic Acid (HA)

A glycosaminoglycan holding up to 1,000 times its weight in water. The body contains approximately 15 grams, with one-third turned over daily.

Melanin

The pigment responsible for skin colour. Overproduction leads to melasma, post-inflammatory hyperpigmentation (PIH), and solar lentigines.

Clinical Assessment Terms

Fitzpatrick Skin Type

A classification system (types I-VI) categorising skin’s UV response. Type I (very fair, always burns) to type VI (deeply pigmented, never burns). Influences laser treatment selection.

Glogau Scale

Photoageing classification from type I (no wrinkles) to type IV (severe wrinkles). Used to assess treatment needs.

Facial Thirds

The face divided into upper, middle, and lower thirds for assessment. Ideal proportions show roughly equal thirds, though ethnic variation is entirely normal.

Safety and Regulatory Terms

GMC / NMC / GDC Registration

Professional regulatory bodies for doctors, nurses, and dentists respectively. Always verify your practitioner’s registration.

Hyaluronidase

An enzyme that dissolves HA fillers. The primary emergency treatment for vascular occlusion. Every clinic performing HA fillers should have it immediately available.

Vascular Occlusion

A rare but serious complication where filler compromises blood supply to tissue. Symptoms include blanching, severe pain, and dusky discolouration. Immediate hyaluronidase treatment is essential.

Frequently Asked Questions

What is the difference between Botox and fillers?

Botulinum toxin relaxes muscles causing dynamic wrinkles. Fillers add volume to smooth static wrinkles and enhance contours. They address different concerns and are often used complementarily.

What does “off-label” mean?

Using a product outside its specifically approved indications. In aesthetic medicine, this is common and legally permissible when performed by qualified practitioners.

What is a “batch number” and why is it important?

Every genuine product carries a batch number for traceability. Your clinic should record it for product recall tracing and authenticity confirmation.

Patient Safety Disclaimer: This glossary is for educational purposes only. Always ensure your practitioner is registered with the appropriate regulatory body (GMC, NMC, or GDC) and holds adequate training and insurance.