Lasers, radiofrequency, ultrasound and injectables: how do the treatment categories differ?
Skin treatments group into a handful of categories defined by what they deliver: light, radiofrequency, focused ultrasound, microwave energy or an injected substance. Knowing which category a menu item belongs to, and that the doctor's settings and technique turn a device into a procedure, makes it easier to see why the same concern can be approached in several ways.
Energy that travels as light
Lasers produce a single wavelength, and each wavelength is absorbed by a particular target such as melanin, water or blood vessels. Pulse duration matters too: picosecond and Q-switched nanosecond lasers fire in extremely short bursts suited to pigment, while fractional lasers divide energy into microscopic columns for resurfacing. Ablative fractional lasers remove tissue and usually involve more recovery; non-ablative versions heat without removing.
Intense pulsed light is not a laser. It emits a broad range of wavelengths filtered for the purpose and is often used for scattered sun spots and redness. Light-based categories share risks that include burns, blistering, post-inflammatory hyperpigmentation and, less often, lightening of the skin.
Radiofrequency, focused ultrasound and microwave
These categories use non-light energy to heat tissue below the surface. They are often discussed for tightening, texture and, in the case of microwave, sweating.
- Monopolar RF: warms a broad volume of dermis through a single treatment tip (Thermage is a familiar example)
- RF microneedling: places radiofrequency heat through fine needles at chosen depths (Potenza and Sylfirm are commonly cited examples)
- HIFU: focuses ultrasound to create small heated points at set depths, including the deeper support layer (Ultherapy is a well-known example)
- Microwave thermolysis: heats the layer containing underarm sweat glands (miraDry is the familiar example)
- Shared risks include burns, swelling, bruising, temporary numbness and, rarely, nerve-related effects
Injectables and skin boosters
Botulinum toxin relaxes targeted muscles to soften dynamic lines and is also used for sweating and jaw muscle bulk. Hyaluronic acid filler restores volume and structure. Both are temporary and involve risks such as bruising, swelling and asymmetry, and filler carries a rare but serious risk of vascular occlusion. Skin boosters, including polynucleotide (PN) products of the Rejuran type, PDRN and hyaluronic acid boosters, are injected in small amounts across an area to support hydration and skin quality rather than to change shape. They commonly leave small bumps and redness for a short time.
Why the device is not the procedure
A menu often lists machine names as though each were a single, fixed treatment. In practice, a device is a tool with adjustable dials: wavelength, energy, depth, density, pulse length and number of passes. The procedure is the plan a doctor builds with those dials for a particular face, skin type and concern, along with decisions about numbing, cooling, sequencing with other categories and aftercare. Two people receiving treatment on the same device can have very different experiences and recovery. This is the main reason this guide focuses on categories and technique rather than ranking machines.
Conditions that change the plan across categories
Certain situations come up repeatedly no matter which category is being considered, and they are worth mentioning at the start of any assessment. Recovery likewise ranges widely, from brief redness that fades quickly to several days of visible flaking, swelling or crusting, depending on the category and settings chosen.
- Pregnancy or breastfeeding
- Active infection, cold sores or broken skin in the area
- Isotretinoin, photosensitizing drugs or blood thinners
- A tendency toward keloids or abnormal scarring
- Darker skin types with a risk of post-inflammatory hyperpigmentation
- Implanted electronic devices or metal near energy treatment zones