SMAS (Superficial Musculoaponeurotic System)
What exactly is the SMAS layer, and why is it crucial for achieving a youthful appearance?
The SMAS layer is one of the most important structural layers for skin tightening and facial rejuvenation. It plays a key role in determining how youthful your face looks. Traditionally, lifting at the SMAS layer was possible only through surgical facelift procedures, which involved shortening and suturing the SMAS layer to pull the face tighter.
Today, advanced skin lifting technology allows the SMAS layer to be targeted without surgery. This “original” method works by delivering high-frequency ultrasound energy beneath the skin to contract and lift the SMAS layer while stimulating new collagen production — something that surgery alone cannot achieve. In the medical field, this is known as Ulthera treatment.
If you’ve ever wondered what the SMAS layer is, why it matters for facial lifting, and how Ulthera can effectively lift to this level, this article will address all your questions.
Table of Content : SMAS
What Is SMAS?
SMAS stands for Superficial Musculoaponeurotic System — a key fibrous tissue layer that envelops the facial muscles. It lies beneath the skin and subcutaneous fat and is the same anatomical layer targeted in surgical facelifts to achieve a tighter, more youthful appearance.
When discussing the facial structure, there are generally three main layers: the epidermis, dermis, and subcutaneous fat layer (subcutis).
- Epidermis : The outermost layer, approximately 0.05–0.1 mm thick, acts as a barrier against pollutants, bacteria, and moisture loss.
- Dermis : A thicker, elastic layer composed mainly of collagen (80–85%) and elastin (2–4%), helping skin maintain a youthful, hydrated, and firm appearance.
- Subcutis : The deepest skin layer, up to 10 cm thick depending on individual fat volume, composed of fat cells (adipocytes & special collagen fibres), grouped into fat lobules, along with collagen proteins and blood vessels. It stores energy and cushions internal structures from impact.
The SMAS layer contains strong, horizontally oriented collagen fibres that provide firmness and resilience. When this layer weakens, it leads to facial sagging — including deep nasolabial folds, drooping cheeks, submental fat (double chin), and marionette lines. For long-lasting and effective skin tightening, lifting must reach the SMAS layer.
What Are the Benefits of the SMAS Layer?
As mentioned earlier, the SMAS layer plays a crucial role in maintaining a youthful facial appearance because it is closely connected to the skin and subcutaneous fat above it. When the SMAS layer is tightened, the overlying skin naturally becomes firmer, resulting in a visibly lifted and more youthful face.
Ulthera for Facial Lifting
Ulthera is a popular, precise, and effective facial lifting device that not only tightens the skin but also helps reduce unwanted fat. This high-energy lifting innovation addresses sagging skin, wrinkles, and deep facial lines, restoring firmness, definition, and a youthful look without surgery or downtime. In addition, it stimulates new collagen production, an effect that surgical facelifts cannot provide.
Beyond facial treatments, Ulthera can also be used to contour and tighten other areas of the body, such as the neck, double chin, décolletage, upper arms, and abdomen. It is ideal for individuals with moderate to significant skin laxity who want a firmer, more contoured facial profile with smooth, youthful-looking skin.
How Ulthera Works on the SMAS Layer
Ulthera uses focused ultrasound — high-frequency sound waves precisely delivered to the SMAS layer in straight, aligned lines. This method provides superior lifting results compared to other non-surgical tightening devices. The treatment delivers heat at a temperature of 60–70°C, forming 1 mm thermal coagulation points that resemble tiny “fish eggs” lined up in a row beneath the skin.
These precise energy points reach deeper than those delivered by standard RF or laser devices.
Ulthera uses transducers at three different depths to address concerns at various skin layers. About 30% of the lifting effect can be felt immediately, with progressive improvement over the next three months.
Ulthera transducer depths:
- 1.5 mm – Targets fine lines and the superficial skin layers (epidermis and dermis).
- 3 mm – Tightens the subcutaneous fat layer (subcutis), which contains fat cells and collagen, helping reduce skin laxity.
- 4.5 mm – Reaches the SMAS (Superficial Musculoaponeurotic System), the same layer targeted in surgical facelifts.
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Summary of the SMAS Layer
The SMAS layer is just as important as other skin layers when it comes to effective lifting. To achieve visible, long-lasting results, tightening must reach the SMAS layer. Ulthera is one of the few devices capable of targeting this depth, delivering focused high-frequency ultrasound energy directly to the SMAS. It is designed to lift and firm sagging skin, making it especially suitable for individuals with minimal facial fat. Results typically last around one year.
Reference
- Whitney ZB, Jain M, Zito PM. Anatomy, Skin, Superficial Musculoaponeurotic System (SMAS) Fascia. [Updated 2024 Jan 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519014/
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