Medical Aesthetics Glossary

Definitions only, not recommendations. If a term below sounds like something you're considering, ask your provider to explain it in the context of your own situation.

Injectables

Botulinum Toxin Injection: A purified protein, marketed under brand names such as Botox, Dysport, Xeomin, and Jeuveau, injected in small amounts into targeted facial muscles. It works by temporarily blocking the nerve signal that tells a muscle to contract, which limits movement in the treated muscle. It is a prescription-only product; in most states it is administered by a licensed medical provider such as a physician, nurse practitioner, physician assistant, or registered nurse. Its effect on muscle movement is temporary and fades over a period of months as normal nerve signaling returns.
Dermal Filler: An injectable material placed beneath the skin's surface to add volume, fill in lines, or reshape an area such as the lips, cheeks, or jawline. Most fillers used in the U.S. are made from hyaluronic acid, though some use other materials such as calcium hydroxylapatite or poly-L-lactic acid. Fillers are regulated as medical devices and are injected by a licensed provider. Depending on the material used, the body gradually breaks down and absorbs the filler over a period of months to a few years.
Hyaluronic Acid (HA): A sugar molecule naturally present in human skin, joints, and connective tissue, where it helps retain moisture. In a synthetic, cross-linked form, it is the base ingredient in most dermal fillers used in medical aesthetics. Different HA fillers vary in thickness and cross-linking density, which affects how firm or fluid the product is and where it is typically placed on the face or body.
Biostimulator (Collagen-Stimulating Filler): A category of injectable that works differently from volumizing fillers. Rather than physically occupying space under the skin, biostimulators, such as those made from poly-L-lactic acid or calcium hydroxylapatite, are formulated to prompt the body's own collagen production at the injection site over time. Because the mechanism relies on the body's gradual response, visible change from this category tends to develop over multiple weeks rather than immediately.
Deoxycholic Acid Injection: An injectable, prescription form of deoxycholic acid, a substance the body produces naturally to help break down dietary fat. Marketed under the brand name Kybella, it is injected directly into localized areas of fat, most often beneath the chin, where it is formulated to disrupt fat cell membranes at the injection site.

Laser & Light-Based Treatments

Intense Pulsed Light (IPL): A handheld device that emits broad-spectrum light in short pulses, as opposed to the single-wavelength beam used by true lasers. The light is absorbed by pigment in the skin, such as sun spots or visible blood vessels, and converts to heat at that target. Because it uses a range of wavelengths, IPL is used to address several surface-level skin concerns with one device rather than one specific target. Facial IPL treatments are sometimes marketed under the term photofacial.
Laser Hair Removal: A treatment that uses a concentrated beam of light at a wavelength absorbed by melanin, the pigment in hair, to heat the hair follicle. Because it targets pigment, the treatment interacts differently with different hair colors and skin tones, and it is most effective on follicles that are in an active growth phase at the time of treatment, which is why it is delivered as a series of sessions spaced weeks apart rather than a single visit.
Fractional Laser: A laser delivery method that treats skin in a pattern of microscopic columns, leaving the surrounding tissue between them untreated, rather than treating the entire surface area at once. This approach is used in both ablative and non-ablative laser devices and is designed to shorten the visible healing period compared with treating the full skin surface in one pass.
Ablative Laser Resurfacing: A category of laser treatment, most commonly using CO2 or erbium lasers, that removes the outer layer or layers of skin using controlled thermal energy. Because it removes tissue, ablative resurfacing involves a period of visible healing, including redness, peeling, and swelling, while the skin regenerates. It is generally performed by, or under the direct supervision of, a physician.
Non-Ablative Laser: A laser treatment category that heats the deeper layers of skin without removing the outer surface layer. Because the top layer of skin stays intact, visible recovery time is generally shorter than with ablative treatments, though the specifics vary by device and treatment area.

Skin Resurfacing

Chemical Peel: A treatment in which an acid-based solution is applied to the skin to remove its damaged outer layers. Peels are generally grouped into superficial, medium, and deep categories, based on the type and concentration of acid used and how deeply it penetrates the skin. Superficial peels, using lower concentrations of acids such as glycolic or salicylic acid, are commonly performed by aestheticians, while medium and deep peels use stronger formulations and are typically performed by, or require the supervision of, a physician.
Microdermabrasion: A mechanical exfoliation treatment in which a handheld device sprays fine crystals or uses a diamond-tipped wand across the skin's surface to physically remove the outermost layer of dead skin cells. It is a non-chemical, surface-level treatment, distinct from chemical peels or laser resurfacing, which work at a deeper level of the skin.
Dermaplaning: A manual exfoliation technique in which a provider uses a surgical scalpel, held at a shallow angle against the skin, to gently scrape away the outermost layer of dead skin cells and fine vellus hair, commonly called peach fuzz, from the face.
Microneedling: A treatment that uses a device with many fine needles to create controlled, superficial punctures in the skin. The punctures are intended to trigger the skin's natural wound-healing response, which includes new collagen and elastin production. Also called collagen induction therapy, it is sometimes combined with topical serums, platelet-rich plasma (PRP), or radiofrequency energy delivered through the needles themselves.
Radiofrequency Microneedling: A variation of microneedling in which the needles also deliver radiofrequency energy beneath the skin's surface as they puncture it, combining mechanical micro-injury with localized heating of the deeper skin layers. Devices in this category are marketed under brand names including Morpheus8 and Vivace, among others.

Body Contouring

Cryolipolysis: A body contouring method, most widely known under the brand name CoolSculpting, that applies controlled cooling to a targeted area of the body to lower the temperature of fat cells beneath the skin. Fat cells are more sensitive to cold than the surrounding skin and tissue; the process is formulated to disrupt fat cells so the body can clear them gradually through its normal metabolic processes over the following weeks. It is a non-surgical, non-invasive procedure.
Radiofrequency Skin Tightening: A treatment that delivers radiofrequency energy through the skin's surface to generate heat in the deeper dermal layers, with the aim of tightening tissue and stimulating collagen production. It is delivered through a handheld device placed against the skin and does not involve needles or incisions.
High-Intensity Focused Ultrasound (HIFU): A treatment that uses focused ultrasound energy to heat tissue at a specific, targeted depth beneath the skin's surface, without directly affecting the layers above it. Depending on the device and the depth setting used, HIFU is applied either for skin tightening, targeting the connective tissue layer addressed in surgical facelifts, or for fat reduction, targeting fat tissue at a deeper level.
Electromagnetic Muscle Stimulation (EMS Body Sculpting): A non-invasive treatment, marketed under brand names including Emsculpt, that uses electromagnetic energy to induce repeated, involuntary muscle contractions in a targeted area, most often the abdomen or buttocks. It is a distinct technology from fat-reduction treatments such as cryolipolysis: EMS devices are designed to act on muscle tissue rather than fat cells.
Laser-Assisted Lipolysis: A minimally invasive body contouring procedure in which a thin laser fiber is inserted beneath the skin through a small incision to heat fat cells, which are then typically removed by suction as part of the same procedure. Because it requires an incision, it is a surgical or minimally invasive procedure performed by a physician, distinct from non-invasive body contouring methods such as cryolipolysis or radiofrequency devices.

Skincare & Facial Treatments

Hydradermabrasion Facial: A multi-step facial treatment that combines water-based exfoliation, suction, and topical serum infusion in a single pass of a handheld device across the skin. It is a category of treatment most associated with the brand name HydraFacial, though similar devices are marketed under other names.
LED Light Therapy: A treatment that exposes the skin to specific wavelengths of light-emitting diode (LED) light, typically delivered through a panel or mask placed over the face. Different light colors correspond to different wavelengths, such as red or blue, and the treatment is often added onto other facial services as an additional step rather than used on its own.
Oxygen Facial: A facial treatment that uses a pressurized device to apply a stream of oxygen to the skin's surface, often combined with a topical serum applied at the same time. It is a spa-category cosmetic treatment rather than a medical procedure.
Medical-Grade Skincare (Cosmeceuticals): An industry term used to describe skincare products sold through physician offices or medical spas, typically distinguished by marketers from over-the-counter retail products by higher concentrations of active ingredients. Medical-grade and cosmeceutical are marketing and industry terms rather than formal regulatory categories: the FDA classifies topical skincare products as either cosmetics or drugs based on their ingredients and the claims made about them, and does not maintain a separate medical-grade classification.
Platelet-Rich Plasma (PRP) Facial: A treatment in which a small sample of the patient's own blood is drawn and processed in a centrifuge to concentrate the platelets, which are then applied to the skin, often in combination with microneedling. It is sometimes referred to informally as a vampire facial. Because it requires a blood draw, it is performed by a licensed provider trained in venipuncture.

Provider & Credential Terminology

Medical Director (Medspa Role): At a medical spa, the medical director is the licensed physician, or in some states another licensed provider, who holds legal responsibility for the medical treatments offered at the facility, including establishing treatment protocols and overseeing the clinical staff who perform procedures. Requirements for the role, including how much on-site presence or direct supervision is required, are set by state law and vary significantly from state to state; there is no single national standard.
Nurse Injector: An informal industry job title, not a separate license, for a registered nurse (RN) or advanced practice registered nurse who performs injectable treatments such as neuromodulators and dermal fillers. In most states, RNs performing these treatments do so under the supervision of, or pursuant to protocols established by, a licensed physician or other supervising provider rather than independently. When verifying credentials, look up the person's underlying RN, LPN, or NP license directly, not the job title.
Aesthetician / Esthetician: A licensed skincare professional trained in non-medical skin treatments such as facials, chemical peels within their scope, microdermabrasion, and waxing. Aestheticians are licensed at the state level, typically through a cosmetology or esthetics board, which is a separate licensing pathway from medical licensure. Their permitted scope of services, and how it overlaps with medical spa treatments, varies by state.
Scope of Practice: A legal term referring to the specific procedures and activities that a licensed professional, such as a physician, nurse, physician assistant, or aesthetician, is permitted to perform under their license, as defined by that state's licensing board. Which provider types may perform which aesthetic treatments, and under what conditions, is determined by scope-of-practice rules that vary from state to state.
Standing Order / Delegation Protocol: A written, physician-authorized set of instructions that allows a non-physician provider, such as a nurse or aesthetician, to perform certain treatments without the physician being physically present for each individual visit. Standing orders and delegation agreements are one mechanism used to structure how a medical spa divides clinical responsibility between its supervising physician and the staff performing treatments; their required form and scope are set by state law and vary accordingly.

Editorial Note

About This Glossary: This glossary is provided for general educational purposes only. It describes what common medical spa terms and technologies are, not whether any specific treatment is safe, effective, or appropriate for any individual, and nothing here should be read as medical advice or a treatment recommendation. Only a licensed medical provider, evaluating a person's individual health history, can advise on what is appropriate for that person. Any credential, licensure, or supervision claim made by a specific business should be independently verified directly with that business or with the relevant state licensing board before booking or receiving treatment.