What is HIFU?
HIFU is the general name for technologies that focus ultrasound waves at a point beneath the skin surface to create controlled heat in the tissue.
In focused ultrasound, sound waves are concentrated at a set depth, much as a magnifying glass gathers light. The tissue heats at that point while the skin surface is relatively spared. In aesthetic medicine, this principle is used to create small points of heat in the deep dermis and at the level of the superficial muscular aponeurotic system (SMAS), stimulating repair and collagen production. Change usually develops gradually over weeks and months.
HIFU is not a brand but a broad technology class. It includes many devices from different manufacturers that differ in energy level, transducer depths, spacing of thermal points and calibration. Some allow the practitioner to view the tissue during treatment and others do not. Ultherapy is a specific device within this class, described as micro-focused ultrasound with visualisation, and it should not be assumed that all HIFU devices behave in the same way.
What is LIFU, and how does it differ from HIFU?
LIFU is a term used in the market for lower-intensity focused ultrasound devices; it has no standard definition in aesthetic medicine, so each device needs to be assessed on its own.
The term LIFU is generally used to mean low-intensity focused ultrasound, and it is chosen to describe devices said to operate at lower energy or with a different focusing pattern. However, it is not an agreed technical category in aesthetic practice, and the same label may be applied by different manufacturers to devices with quite different characteristics. Low-intensity ultrasound is also studied for unrelated purposes in medical research, which can add to the confusion.
It is therefore not appropriate to make general claims that HIFU or LIFU is superior or more comfortable. Lower energy may be associated with less discomfort, but the effect in the tissue may differ accordingly. A meaningful comparison is possible only once the device's energy level, target depth, imaging capability, manufacturer and registration status in Türkiye are known, and this is something the physician can help you interpret.
When is focused ultrasound considered, and what does it not do?
It may be considered for mild to moderate laxity of the brow, jawline, under the chin and neck; it does not replace lost volume or remove significant excess skin.
Focused ultrasound is usually discussed for people whose tissues have begun to loosen slightly while skin quality is still reasonably preserved. A softening jawline, laxity under the chin and on the neck, and a slightly lowered brow are the main concerns assessed. Some devices are also marketed for body areas; whether such uses are consistent with the device's registered indications should be checked, and this question can be raised at consultation.
Focused ultrasound does not replace volume lost with age and is not intended to achieve what surgery does for advanced sagging. In people who already have little facial fat, treatment delivered at an inappropriate depth may lead to unwanted volume loss, which should be kept in mind. Where volume loss is the main concern, fillers or biostimulators may be more relevant, and botulinum toxin for expression lines; the plan is set by the physician.
Who may not be suitable?
Treatment may be postponed or not advised during pregnancy, with active infection, open wounds or skin disease in the area, and with certain implants in the treatment zone.
Treatment is usually postponed during pregnancy and breastfeeding. If there is a cold sore, active acne, eczema, an open wound or infection in the area, treatment is usually delayed until it has healed. Metal implants and recent fillers or threads in the area are discussed individually at consultation. For people with very thin skin and very little facial fat, whether treatment is appropriate at all is weighed carefully, with the depth of any treatment in mind.
Blood thinners, bleeding disorders, poorly controlled chronic illness and a tendency to scar may also affect the plan. It is important to share your medical history, current medication and previous aesthetic treatments. Which device might be used, and whether it is suitable for you, is assessed by the physician in light of all this information, and another specialist's opinion may be sought before a decision where appropriate.
What does treatment involve, and what are the risks?
Treatment is applied from the skin surface with gel, and most people return to daily activities soon afterwards; redness, swelling and tenderness are common, while burns and nerve irritation are rare.
Before treatment, the area is cleansed, treatment lines are marked and ultrasound gel is applied. When energy is delivered you may feel deep warmth or prickling, the intensity of which depends on the device, energy level and area. Afterwards, mild redness, swelling and tenderness to touch may occur and usually settle within a few days. Sun protection and following the physician's after-care advice are recommended during recovery.
Rarely, bruising, temporary numbness, temporary changes in facial movement due to nerve irritation, burns or linear marks on the skin have been reported. Device calibration, the use of genuine transducers and depth selection are key to reducing these risks. Treatment should therefore take place in a licensed healthcare facility, with a registered device and under a physician's responsibility, with the plan decided at a face-to-face consultation.
Frequently asked questions
Is HIFU the same as Ultherapy?
Ultherapy is a specific device within the focused ultrasound class that provides imaging during treatment. HIFU is a general name covering many different devices in this class.
Is LIFU more comfortable?
Devices described as working at lower energy may cause less discomfort, but their effect in the tissue may also differ. A comparison can only be made once the device's technical specifications are known.
How many HIFU sessions are needed?
It varies with the device and the indication. Some devices are used in a single session, others in a short course; repeat intervals depend on your response.
Can HIFU cause fat loss in the face?
Unwanted volume loss has been described when treatment is delivered at an inappropriate depth or in people with little facial fat. Suitability and depth selection are therefore planned carefully by the physician.
How can I tell whether a HIFU device is reliable?
You can ask for the manufacturer, model, registration status in Türkiye and whether the transducers are genuine. Treatment should take place in a licensed healthcare facility under a physician's responsibility.
If I see no change right after HIFU, does that mean it didn't work?
No; not seeing a noticeable change straight after HIFU is expected. The effect of HIFU depends on collagen production stimulated by the points of heat created in the tissue, so change usually begins within a few weeks and develops gradually over several months. HIFU is therefore usually assessed at a review a few months after treatment, by comparison with photographs taken beforehand.
Are at-home HIFU devices safe?
At-home HIFU devices should not be assumed to be safe. The specifications, actual energy and registration status of devices sold for home use are not always clear, and incorrect use can cause burns, blistering or numbness. Clinical focused ultrasound is used under a physician's responsibility, with depth and energy chosen for the individual. If problems arise after home use, stop and see a doctor.
What should I do if I have numbness or line-shaped marks after HIFU?
Mild numbness or tingling after HIFU fades on its own within a few days to a few weeks in most people. If you notice line-shaped redness, blistering, a burn-like appearance or changes in facial movement, photograph the area and contact the physician who treated you without delay. Nerve-related movement changes are mostly reported as temporary, but they need medical follow-up.
Can I have HIFU in the summer?
Yes, because HIFU does not break the skin surface, it can also be planned in the summer months; sun-related restrictions are generally fewer than with microneedling radiofrequency or laser treatments. Even so, during the few days of redness and sensitivity after HIFU, it is advisable to avoid intense sun and heat, use sunscreen regularly and not to have treatment while you have noticeable sunburn.
Sources (3)
- Aesthetic Surgery Journal: A Systematic Review of High-Intensity Focused Ultrasound in Skin Tightening and Body Contouring (2025)
- Journal of Cosmetic Dermatology: Microfocused ultrasound with visualization: Consensus on safety and review of energy-based devices (2022)
- Journal of Clinical and Aesthetic Dermatology: Customized Treatment Using Microfocused Ultrasound with Visualization for Optimized Patient Outcomes: A Review of Skin-tightening Energy Technologies and a Pan-Asian Adaptation of the Expert Panel's Gold Standard Consensus (2021)
This content is for general information and does not replace a personal medical assessment.