What causes smile lines (parentheses wrinkles) on both sides of the mouth corners, and how can they be treated?
In general, smile lines (nasolabial folds) on both sides of the mouth may result from aging, poor lifestyle habits, sun exposure, frequent facial expressions, and skin aging. These lines can be improved through skincare, massage, and adequate sleep. Alternatively, they can be reduced or eliminated with treatments such as hyaluronic acid injections, botulinum toxin type A injections, autologous fat grafting, thread lifting, or facelift surgery. The effectiveness varies from person to person, so it is recommended to consult a qualified medical professional to determine the most suitable approach.
1. Skincare: Choose moisturizing products suitable for your skin type, such as creams or lotions containing ingredients like hyaluronic acid and glycerin. Hyaluronic acid can absorb large amounts of water, helping the skin stay plump and hydrated. After cleansing in the morning and evening, apply the moisturizer evenly to the face—especially the areas around the corners of the mouth—and gently massage until fully absorbed.
2. Massage: Using the index and middle fingers of both hands, start at the center of the chin and gently lift and massage upward along the jawline toward the temples. Repeat this motion 10–15 times per session. This helps improve facial blood circulation, tones facial muscles, and reduces the visibility of nasolabial folds.
3. Adequate Sleep: Ensure 7–9 hours of high-quality sleep each night to support skin cell renewal and collagen synthesis. During sleep, the body undergoes various physiological adjustments, including increased blood flow to the skin, which enhances nutrient delivery to skin cells, promoting healthier skin and reducing the formation of smile lines.
Detailed Analysis of Smile Line Treatments:
Cause |
Aging |
Poor Lifestyle Habits | Sun Exposure |
Frequent Facial Expressions | Skin Aging |
Explanation |
Aging leads to collagen loss, resulting in smile lines. |
Long-term side-sleeping may compress the skin around one side of the mouth, accelerating wrinkle formation. | UV radiation can damage skin’s connective tissue and elastic fibers. |
Frequent facial movements, especially smiling, may cause micro-tears in the tendon fibers around the nasolabial area, forming smile lines. | As skin ages, the skin around the mouth gradually sags due to gravity, forming smile lines. |
Treatment |
Hyaluronic Acid Injection |
Botulinum Toxin Type A Injection | Autologous Fat Grafting |
Thread Lifting | Facelift Surgery |
Mechanism |
Hyaluronic acid is injected into the smile line area to quickly fill depressions and tighten the skin. |
The injection blocks acetylcholine release at neuromuscular junctions, preventing excessive skin pulling. |
Harvested fat from the patient's own body is transplanted to the facial smile line area to fill and smooth wrinkles. |
Absorbable protein threads are implanted between the dermis and subcutaneous tissue to lift and tighten sagging skin around the mouth. | Loose skin is tightened, excess skin is removed, and the area is re-sutured. |
Duration |
6–12 months |
3–6 months | 2–3 years |
2–3 years | 3–5 years |
Reference Price |
1,000–3,000 RMB/session |
1,500–3,000 RMB/session | 3,000–6,000 RMB/session |
3,000–8,000 RMB/session | 5,000–10,000 RMB/session |
Advantages |
1. Non-invasive and scar-free |
1. Simple and quick procedure |
1. No immune rejection |
1. Minimally invasive |
1. High precision |
Potential Risks |
1. Bruising |
1. Muscle weakness |
1. Bleeding |
1. Swelling and pain |
1. Scarring |
After treatment, avoid contact with water or scratching the treated area. Eat more green vegetables and fruits, and include nutrient-rich foods such as meat and eggs to enhance nutrition and support facial recovery.
