Why should we avoid direct sunlight after a HIFU procedure?

HIFU therapy (High Intensity Focused Ultrasound) is a modern non-invasive method for skin tightening and rejuvenation. It activates the production of new collagen in the deep dermal layers without damaging the skin surface. After the procedure, a natural regeneration process begins, which lasts for weeks, even months. However, during this sensitive period, external factors, especially direct sunlight, can have a serious impact on the final result.

How do UV rays affect the skin?

Ultraviolet rays, especially UVA, penetrate the deep layers of the skin and destroy collagen fibers. This leads to premature aging, the appearance of age spots, loss of elasticity and fine wrinkles. After HIFU, when the skin is more sensitive, the risk of such reactions is even higher.

Reasons to avoid direct sunlight after HIFU:

• Damage to newly formed collagen: UV rays can destroy collagen fibers before they have stabilized, reducing the effect of the therapy.
• Increased risk of pigmentation: After HIFU, the skin may be slightly inflamed, which increases the risk of post-inflammatory hyperpigmentation upon sun exposure.
• Delay in recovery: Excessive exposure to direct sunlight can cause swelling, redness, or irritationthat will extend the recovery period.

Scientific perspective on UV influence after HIFU

A recent study in mice exposed to UVB and subsequent HIFU treatment showed significant improvement in collagen structure and reduction in signs of photoaging — compared to the UVB-only group, dermal thickness normalized and TGF-β concentrations doubled, while the MMP-3 enzyme decreased significantly. pubmed.ncbi.nlm.nih.gov+1pubmed.ncbi.nlm.nih.gov+1. A study on human skin demonstrated that UV radiation reduces the expression of the TGF-β/Smad signaling pathway. This leads to a greatly reduced synthesis of type I collagen. pubmed.ncbi.nlm.nih.gov.

The data presented allow a reasonable assumption: HIFU can stimulate collagen remodeling, but if the skin is exposed to UV while the active repair process is still ongoing, the sun blocks key cellular responses (such as TGF-β signaling) and activates destructive enzymes (MMP-1 and MMP-9). The process could potentially not only reduce the effect, but also interfere with it at the cellular level.

How to protect ourselves from direct sunlight?

1. Use broad spectrum sunscreen SPF 50+, even if you don't plan on direct sun exposure.
2. In the first 10 days after therapy, avoid active walks during sunny hours - especially between 11:00 and 16:00.
3. Wear hat with brim, sunglasses and seek shade when you are outside.
4. Apply moisturizing and soothing productsrecommended by a specialist.