Scar Treatment Facts

There are many scar treatment options available on the market these days but most treatments are not backed by scientific evidence. Here are the most frequently recommended treatments with the scientific verdict for each:

VITAMIN C
One of skin's main components is collagen. Scars heal through new collagen formation. Untreated skin produces unorganized, haphazard collagen. Stable forms of vitamin C help to organize collagen ^1,2. Improved collagen formation causes faster and more cosmetic scar healing ¹. Vitamin C also decreases inflammation ^3,4,5,6 and lightens dark skin pigmentation ³ like dark scars, brown spots and even melasma.
Scientific verdict: Vitamin C scar treatments work.

SILICONE GEL AND SILICONE SHEETING
Silicone improves the appearance of both old and new scars ^7,8,9. Exactly how silicone works is unknown. One theory is that silicone changes the electronic charges on the collagen molecules in the skin which improves the way the collagen lines up in the scar. Silicone may also decrease levels of TGF-beta2 (which is increased in scars). Some people find silicone sheets a little cumbersome because they can interfere with clothing and make-up. Silicone gel (Dimethicone) is as effective as silicone sheeting but is much easier to apply ⁷.
Scientific verdict: Scar silicone treatments improve scar healing.

VITAMIN E (Tocopherol)
Topical vitamin E as a scar treatment has no effect on, and actually WORSENS the appearance of scars in up to 90% of adults ^10,11. 33% of users developed a contact dermatitis to vitamin E (redness, itching and flaking) ^10,11. American dermatologists ¹² and Canadian pediatricians recommend completely avoiding scar creams containing vitamin E ¹³.
Scientific verdict: Vitamin E scar treatments don't work.

TOPICAL STEROIDS
Independent studies have shown that topical steroids have no effect in reducing scar thickness or the cosmetic appearance of scars ¹⁴.
Scientific verdict: Topical steroid scar treatments don't work.

BOTANICALS (plant extracts):
The most commonly recommended "natural scar treatments" are:

Aloe Vera: Aloe accelerates wound healing ^15,16, decreases inflammation ^15,16, stimulates new skin growth through amino acids ^15,16, and promotes healthy healing in the deepest skin layers ^15,16.
Scientific verdict: Aloe vera improves scar healing.

Licorice (Stearyl Glycyrrhetinate): Licorice is a strong anti-inflammatory ^17,18. It accelerates skin renewal ¹⁹ and lightens dark pigment and brown spots including melasma ^19,20. Licorice also has anti-acne effects both in terms of prevention and treatment ²¹.
Scientific verdict: Licorice extract improves scar appearance.

Onion extract (eg. Mederma skin care): Several scientific studies in humans and animals have focused on onion extract, one of the main ingredients in Mederma® skin care products. All showed no benefit from topical use ^22-24. Mederma performed no better than plain petroleum gel (or Vaseline^®) ²⁵ for scar redness, itchiness, pain, burning, thickness and overall scar appearance.
Scientific verdict: Onion extract does not improve scar appearance.

In summary, scientific studies support the scar treatment claims of vitamin C, silicone and some natural plant extracts like aloe vera and licorice. There is no scientific evidence that vitamin E, topical steroids or onion extract improve scar appearance.

References:

1. Fitzpatrick RE, Rostan EF. Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage. Dermatol Surg 2002;28:231-236.

2. Nusgens BV, Humbert P, Rougier A, et al. Topically applied vitamin C enhances the mRNA level of collagens I and III, their processing enzymes and tissue inhibitor of matrix metalloproteinase 1 in the human dermis. J Invest Dermatol 2001 Jun;116(6):853-859.

3. Farris PK. Topical vitamin C: a useful agent for treating photoaging and other dermatologic conditions. Dermatol Surg 2005;31:814-818.

4. Carcamo JM, Pedrazza A, Borquez-Ojeda O, et al. Vitamin C suppresses TNF alpha-induced NK kappa B activation by inhibiting I kappa B alpha phosphorylation. Biochemistry 2002;41:12995-300002.

5. Senftleben U, Karin M. The Ikk/NF-B pathway. Crit Care Med 2002;30S18-26.

6. Alster TS, West TB. Effect of topical vitamin C on postoperative carbon dioxide laser resurfacing erythema. Dermatol Surg 1998;24:331-334.

7. Mustoe TA. Evolution of silicone therapy and mechanism of action in scar management. Aesth Plast Surg 2008;32:82-92.

8. Chan KY, Lau CL, Adeeb SM, et al. A randomized, placebo-controlled, double-blind, pro-spective clinical trial of silicone gel in prevention of hypertrophic scar development in median sternotomy wound. Plast Reconstr Surg 2005;116:1013-1020.

9. Kuhn, M. A., Moffit, M. R., Smith, P. D., et al. Silicone sheeting decreases fibroblast activity and downregulates TGFbeta2 in hypertrophic scar model. Int. J Surg Invest 2: 467, 2001.

10. Baumann LS, Spencer J. The effects of topical vitamin E on the cosmetic appearance of scars. Dermatol Surg1999;25:311-315.

11. Jenkins M, Alexander JW, MacMillan BG, et al. Failure of topical steroids and vitamin E to reduce postoperative scar formation following reconstructive surgery. J Burn Care Rehabil 1986 Jul-Aug;7(4):309-12.

12. Zurada JM, Kriegel D, Davis IC. Topical treatments for hypertrophic scars. J Am Acad Dermatol 2006 Dec;55(6):1024-31.

13. Khoosal D, Goldman RD. Vitamin E for treating children's scars. Does it help reduce scarring? Can Fam Physician 2006 Jul;52:855-6.

14. Jenkins M, Alexander JW, MacMillan BG, et al. Failure of topical steroids and vitamin E to reduce postoperative scar formation following reconstructive surgery. J Burn Care Rehabil 1986 Jul-Aug;7(4):309-12.

15.Davis RH, DiDonato JJ, Hartman GM, et al. Anti-inflammatory and wound healing activity of a growth substance in Aloe vera. J Am Podiatr Med Assoc 1994;84(2):77-81.

16.Davis RH, Rosenthal KY, Cesario LR, Rouw GA. Processed Aloe vera administered topically inhibits inflammation. J Am Podiatr Med Assoc 1989;79(8):395-7.

17.Yokota T, Nishio H, Kubota Y, Mizoguchi M. The inhibitory effect of glabridin from licorice extracts on melanogenesis and inflammation. Pigment Cell Res. 1998 Dec;11(6):355-61.

18.Tsukahara M, Nishino T, Furuhashi I, Inoue H, Sato T, Matsumoto H. Synthesis and inhibitory effect of novel glycyrrhetinic acid derivatives on IL-1 beta-induced prostaglandin E(2) production in normal human dermal fibroblasts. Chem Pharm Bull (Tokyo). 2005 Sep;53(9):1103-10.

19.Amer M, Metwalli M. Topical liquiritin improves melasma. Int J Dermatol. 2000 Apr;39(4):299-301.

20.Fu B, Li H, Wang X, Lee FS, Cui S. Isolation and identification of flavonoids in licorice and a study of their inhibitory effects on tyrosinase. J Agric Food Chem. 2005 Sep 21;53(19):7408-14.

21.Nam C, Kim S, Sim Y, Chang I. Anti-acne effects of Oriental herb extracts: a novel screening method to select anti-acne agents. Skin Pharmacol Appl Skin Physiol. 2003 Mar-Apr;16(2):84-90.

22.Jackson BA, Shelton AJ. Pilot study evaluating topical onion extract as treatment for postsurgical scars. Dermatol Surg 1999;25:267-269.

23.Saulis AS, Mogford JH, Mustoe TA. Effect of Mederma on hypertrophic scarring in the rabbit ear model. Plast Reconstruct Surg 2002;110:177-183.

24.Clarke LF, Baker B, Trahan C, et al. A prospective double-blinded study of Mederma skin care vs. placebeo for post-traumatic scar reduction. Cosmetic Dermatol 1999;19-28.

25.Chung VQ, Kelly L, Marra D, et al. Onion extract gel versus petrolatum emollient on new surgical scars: a prospective double-blinded study. Dermatol Surg 2006;32:193-197.