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Scars: Can Hyaluronic Acid Fade Them?

The skin's healing process after trauma is not flawless, and it is common for scars to persist, which can be both unsightly and uncomfortable. Acne scars, chickenpox marks, stretch marks, cuts... There are many types. They all have one thing in common: they are difficult to treat. Could hyaluronic acid, one of the most commonly used active ingredients in the field of cosmetics, be of help?

Summary
Published May 14, 2024, updated on May 14, 2024, by Pauline, Head of Scientific Communication — 6 min read

Healing: What is the mechanism of action of hyaluronic acid?

An essential component of the extracellular matrix of the dermis, hyaluronic acid plays a significant role in numerous embryological, physiological, and pathological processes, including wound healing. It notably possesses angiogenic properties, demonstrated in in vitro tests, meaning it stimulates the formation of new blood vessels from a pre-existing network. Additionally, hyaluronic acid alters vascular permeability by activating endothelial cells, which are involved in initiating the wound healing process. Lastly, this molecule facilitates the binding between certain microbial membrane factors and Toll-like receptors, promoting wound healing.

The effects of hyaluronic acid on wound healing vary depending on its molecular weight. Indeed, high molecular weight hyaluronic acid plays a crucial structural role within the extracellular matrices of tissues by regulating their hydration and plasticity. It also protects cells from enzymatic, viral, or bacterial attacks, which could potentially disrupt the healing process. When it is hydrolyzed or its molecular weight is lower, hyaluronic acid acts as a signaling molecule during angiogenesis and tissue repair.

Hyaluronic Acid and Healing: A Closer Look at Clinical Studies.

To diminish the appearance of scars, hyaluronic acid can be used either topically or through injection, each method having its own unique advantages and disadvantages.

The effectiveness of hyaluronic acid in topical application for diminishing scars has been demonstrated in several clinical studies, conducted on volunteers with various types of scars. The results, compiled in the table below, seem to indicate that hyaluronic acid is a true aid in the re-epithelialization of the skin.

StudyNumber of ParticipantsType of ScarProtocolResults
ERDEI & al. (2012)60Partial thickness burn (on average 3% of the total body surface area)Daily application of a gel containing hyaluronic acid and zincAverage wound reduction of 50% was observed by the 5th day, and complete epithelialization was noted in 56 patients by the 21st day
SCUDERI & al. (2013)40Persistent leg ulcerDaily application of a cream containing hyaluronic acid and collagenaseNo improvement for 4 patients, moderate improvement for 4, good improvement for 32
ALLAERT & al. (2013)38UlcerDaily application of a hyaluronic acid compressAfter 45 days, there was an average reduction in ulcer size of 73%

When it comes to the effects of hyaluronic acid injections on scars, the evidence is more abundant and concrete. Their effectiveness is based on the filling effect of the active ingredient: by slightly elevating the skin at the scar site, it helps to make it less visible. However, while hyaluronic acid injections are useful for treating indented scars, their effectiveness is limited on hypertrophic scars, which exhibit an overgrowth of skin tissue. It's also important to keep in mind that hyaluronic acid injections carry risks of side effects (infections, allergic reactions, edema, inflammation...) and should not be undertaken lightly.

StudyNumber of ParticipantsType of ScarProtocolResults
BLOMSTER & al. (2018)12Atrophic Acne Scars3 injections of hyaluronic acid at 4-week intervalsNo improvement for 1 patient, moderate improvement for 1, good for 9, and very good for 1
DE FRANCESCO & al. (2019)41Hypertrophic Scars2 injections of hyaluronic acid at 2 weeks apartAverage improvement in the appearance of scars quantified at 22%
FRIEDMAN & al. (2019)12Atrophic Acne Scars2 injections of hyaluronic acid at 4-week intervalsMinimal improvement for 2 patients, moderate for 8, and significant for 2
NOBILE & al. (2024)32Stretch Marks4 injections of 10 mL of low molecular weight hyaluronic acid + 6 amino acids at 2-week intervalsAverage improvement in participants' quality of life assessed at 19%

Sources

  • GALL Y. Hyaluronic Acid: Structure, Metabolism, and Implication in Wound Healing. Annals of Dermatology (2010).

  • ERDEI I. & al. Treatment of partial thickness burns with Zn-hyaluronan: insights from a clinical pilot study. Annals of Burns and Fire Disasters (2012).

  • SCUDERI N. & al. A novel correlation between hyaluronic acid and collagenase in wound healing: an open study. European review for medical and pharmaceutical sciences (2013).

  • ALLAERT F. A. & others. Efficacy and safety of a gauze pad infused with hyaluronic acid for the treatment of leg ulcers of venous or mixed origin: a double-blind, randomized, controlled trial. International Wound Journal (2013).

  • BLOMSTER S. & al. Efficacy and Safety of Acne Scar Treatment Using Nonanimal Stabilized Hyaluronic Acid Gel. Dermatologic Surgery (2018).

  • DE FRANCESCO F. & al. Managing Pathological Scars through the Injection of Auto-Cross-Linked Hyaluronic Acid: An Initial Prospective Clinical Study. Aesthetic Plastic Surgery (2019).

  • FRIEDMAN O. & al. Dual-plane hyaluronic acid treatment for atrophic acne scars. Journal of Cosmetic Dermatology (2019).

  • NOBILE V. & al. The addition of low molecular weight hyaluronic acid to six specific amino acids in the treatment of striae alba (SA): An observational study. Aesthetic Plastic Surgery (2024).

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