How Facial Fat Changes with Age

The full text of my column published in the April 2025 issue of D&PS.

In the late 1990s, Professor Nancy Etcoff's team at Harvard Medical School published findings that even three-month-old babies looked longer at faces adults considered attractive. In Survival of the Prettiest, Etcoff described the pursuit of beauty as an instinctive, biologically ingrained human response. Research observing which faces very young babies prefer points to the importance of an oval contour: the soft, three-dimensional shape sometimes called a heart line. The lateral cheek is aesthetically significant enough to have its own term, “lateral cheek hollowness,” and fat grafting is often used to restore volume here. Many clinicians caution, however, that adding fat to areas without bony support in people over 40, particularly beneath the lateral cheekbone, may cause sagging and make the face look older.

Figure 1. Yase Onna (left), portrayed as an unappealing character in traditional Japanese masked theater, and Kohime (right), portrayed as beautiful and virtuous. Source: https://commons.wikimedia.org

How does youthful facial fat differ from aging facial fat?

The concept of “facial fat fitness” describes this distinction. Young, healthy facial fat has little inflammation. When its volume increases, it tends to do so by increasing the number of fat cells rather than their size, creating smooth fullness. As chronic inflammation increases with age, volume gain instead tends to occur through enlargement of individual fat cells. The premise is that this cellular enlargement contributes to the sagging fat commonly seen in an older face.

Two approaches may help prevent this. One is periodic treatment with RF devices operating at different frequencies or with microwave devices. These treatments encourage production of heat shock proteins that suppress various inflammatory cytokines. Another is regular use of stem-cell-derived products with anti-inflammatory effects.

Figure 2. Young adipocytes and inflamed, aging adipocytes. White adipose tissue expansion in obesity: excess calories can produce either healthy expansion through adipocyte hyperplasia, which protects against metabolic complications, or unhealthy expansion through adipocyte hypertrophy, which promotes them. WAT, white adipose tissue; T2D, type 2 diabetes; NAFLD, nonalcoholic fatty liver disease; CVD, cardiovascular disease. Source: Int J Mol Sci. 2019 May 13;20(9):2358. doi:10.3390/ijms20092358.

Figure 3. Hyperplasia and hypertrophy in relation to adipocyte volume. Source: Elucidating the Mechanisms of Adipocyte Differentiation and Remodeling. https://scienceon.kisti.re.kr/srch/selectPORSrchReport.do?cn=TRKO202000006674#;

Figure 4. Superficial cheek fat compartments (left) and deep cheek fat compartments (right).

Figure 5. Different types of skin. (A) Human skin in the head and neck region: (1) dermis; (2) superficial fat, here dermal white adipose tissue (dWAT); (3) panniculus carnosus, here the superficial musculoaponeurotic system (SMAS); (4) deep fat, here subcutaneous white adipose tissue (sWAT); (5) deep fascia/periosteum; and (6) deep structures, here muscle. (B) The usual arrangement of skin in most mammals: (1) dermis; (2) panniculus adiposus, here sWAT; (3) deep fascia/periosteum; and (4) deep structures, here muscle. Source: The Facial Adipose Tissue: A Revision, Ilja Kruglikov et al., Facial Plast Surg. 2016;32:671–682.

Subcutaneous adipose tissue also has a major influence on skin aging. It contains a specialized depot known as dermal white adipose tissue, or dWAT, that differs markedly from conventional adipose tissue. These responsive dermal fat cells undergo very rapid transdifferentiation and strongly affect surrounding tissues. Reports that they contribute substantially to the production of collagen and fat, both directly relevant to skin aging, have prompted ongoing research. Dermal adipocytes respond particularly quickly to thermal stimulation, including an immediate increase in cell volume. Appropriate use of energy-based devices can therefore elicit this response, expanding dWAT promptly while also encouraging new collagen and fat-cell formation. Repeated stimulation produces a greater and more sustained effect in this tissue, providing a rationale for repeated treatment.

How do energy-based devices such as Thermage and Ultherapy affect facial fat?

Patients often ask how energy-based devices affect fat. Although they are now less commonly used in clinical practice, lasers at wavelengths such as 1064 nm, 1320 nm, and 980 nm were once used to break down fat. Ultherapy, a HIFU device, initially also attracted interest for fat reduction, much like LipoSonix.

Laser	System	Wavelength	Power	Rep Rate
SMARTLIPO	Nd:YAG	1064	10W	40Hz
SMART LIPO MPX	Nd:YAG	1064/1320	20/12W	40Hz
LIPOLITE	Nd:YAG	1064	12W	50Hz
PROLIPO	Nd:YAG	1064/1319	25W	50Hz
LIPOTHERME	Diode	980	25W	?
COOLLIPO	Nd:YAG	1320	15W	50Hz
ACCUSCULPT	Nd:YAG	1444	12W	40Hz

Figure 6. Energy-based devices previously used for fat reduction.

An early Thermage paper, “Overtreatment Effects Associated with a Radiofrequency Tissue Tightening Device: Rare, Preventable, and Correctable with Subcision and Autologous Fat Transfer” [Rhoda S. Narins et al., Dermatologic Surgery 32.1 (2006):115–124], reported cases of multiple facial hollows after treatment that were corrected with fat grafting. Research associated with truSculpt reported RF-induced adipocyte death. In “Hyperthermic Injury to Adipocyte Cells by Selective Heating of Subcutaneous Fat with a Novel RF Device: Feasibility Studies” [Walfre Franco et al., Lasers in Surgery and Medicine 42:361–370 (2010)], raising the temperature from 45°C to 50°C during one minute of heating reduced cell survival from 89% to 20%. Heating at 45°C for three minutes reduced survival to 40%.

The tissue effects of energy-based devices depend on both temperature and exposure time. Skin, fat, and nerves are among their principal potential targets.

(To be continued in the next issue)

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