Thank you for your question. At age 30 and at a healthy weight, lack of definition beneath the chin is not necessarily because of true submental fullness. When evaluating this area, it is important to look at the chin, jawline, and neck together. A chin that is relatively underprojected or short can make the submental area appear fuller and the jawline less defined, even when there is relatively little excess fat. Depending on your anatomy and goals, options may include chin filler, chin augmentation with fat grafting, a chin implant, or sliding genioplasty to improve chin projection and/or vertical length. If there is also localized submental fat, conservative liposuction or another form of fat reduction may sometimes be considered. In some patients, improving the chin itself can create substantially better harmony and definition without needing aggressive treatment of the neck. The deeper anatomy of the neck also matters. The position of the hyoid bone and associated muscles can influence the natural cervicomental angle and the contour beneath the chin. This is important because not every submental contour is caused by excess fat, and simply removing more fat is not always the appropriate solution and can instead create an unnatural look. Ultimately, the best treatment depends on determining how much of what you are seeing comes from chin position and proportions, localized fat, skin, and deeper neck anatomy. An in-person examination and consultation with a plastic surgeon who specializes in facial aesthetics, including assessment of your bite and skeletal proportions, would help determine which approach—or combination of approaches—could provide the most natural improvement while preserving your facial identity.