Ingredient Spotlight: Retinol

Vitamin A is an oil-soluble vitamin critical to healthy immune function, vision, reproduction, and cellular communication.  The human body is incapable of synthesizing Vitamin A, relying instead on dietary and/or supplemental replenishment. Applied topically, it speeds cellular turnover, inhibits collagen breakdown, and normalizes keratinization.  Multi-faceted skin benefits make it ideal over-the-counter solution for both aging and acne-prone skin. Also known as Retinol, a prominent member of the retinoid family.

 

Skin Benefits:

• Brightens: Speeds cellular turnover, fading post-inflammatory pigmentation and discoloration. Improves cellular turnover by 1200% in 7 days (0.4% retinol applied once daily). 

• Firms: Supports Collagen Production (glycosaminoglycan and procollagen I) and increases epidermal proliferation (thickening deeper layers). 

• Increases Collagen type I by 300% in 7 days (0.4% retinol applied once daily).

• Improves extracellular matrix (ECM) proteins, fibronectin by 220% and elastin by 400%, in 7 days (0.4% retinol applied once daily).

• Increases epidermal thickness by 210% in 7 days (0.4% retinol applied once daily).

• Protects/Repairs: Antioxidant function defends and improves UVA/UVB damage.

• Smooths: Normalizes skin keratinization and reduces pore size. Decreases dermal collagen fibril disorganization by 48% in 7 days (0.4% retinol applied once daily).

• Anti-Acne: Reduces sebum (oil) production and slows bacterial (Propionibacterium acnes) growth often associated with acne.

Efficacy:

• Effective in topical applications ranging between 0.01-2% concentrations.
• Optimal retinol activation, also known as esterfication, occurs at a pH range of 5.0-6.0.
• Always check the ingredient label for retinol prior to purchase. Many "retinol creams" contain zero retinol.  
• Whether new to retinol or avid fan, it’s best to look for skincare that indicates the strength of the retinol provided to avoid underwhelming results. If strength is not specified, a potency of less than 0.25% can be assumed. 
• Retinol degrades quickly with exposure to light and heat, so choose airless/opaque containers, store in a dark/cool place, and only use retinol at night.
• Use can make skin more vulnerable to sun damage, so sunscreen is more important than ever.
• Introduce retinol slowly (every other night) and at lower strengths to diminish the risk of retinization, also known as retinoid dermatitis.  Characterized by peeling, flaking and mild redness caused by the accelerated cellular turnover and rapid exfoliation.  See Retinol Hacks for more tips and tricks.
• Skin benefits rely of skin receptors to convert retinol into retinal and then to retinoic acid, also known as tretinoin or Retin-A.
• Generally, retinol is considered 10x milder than prescription-strength retinoids and 2x stronger than Retinyl Esters (Retinyl Palmitate).
• Combinations with Vitamin B3 (Niacinamide), Hyaluronic Acid, Peptides, or Soy help to improve the tolerability of retinol.  To boost antioxidant effects of retinol, consider pairings with Alpha Lipoic Acid (Thioctic Acid) or CoQ10 (Ubiquinone).  For troubled skin, look for anti-inflammatory ingredients like green tea, MSM (Dimethyl Sulfone), Sea Fennel or Vitamin B5 (Panthenol).
• Don't mix Retinol with:

• Vitamin C (Ascorbic Acid).  May be mixed with other Vitamin C derivatives, like Tetrahexyldecyl Ascorbate or Ascorbyl Palmiatate. Ironically, Ascorbic Acid skincare used alternately, can actually improve retinol performance for aging skin.

• AHAs and BHAs, but can be used individually within your skincare routine. 

• Warning: Anyone pregnant, planning pregnancy or breastfeeding should consult with their Physician prior to using retinol or other retinoid skincare.

Sources:

• Synthetic

• Broccoli, Carrots, Cranberry, Red Raspberry, Rosehip, Seabuckthorn, Pumpkin,

• Beef Liver, Lamb Liver, Herring, Cod Liver Oil

 

References:

• Informa Healthcare, 2010:115-20, Encyclopedia of Dietary Supplements. 2nd ed. London and New York.

• International Life Sciences Institute, 2006:157-83, Vitamin A. In: Bowman B, Russell R, eds Present Knowledge in Nutrition. 9th ed. Washington, DC.

• Dermatologic Surgery 2003;29:155-160, Clinical trial of bleaching treatment with 10% all-trans retinol gel.

• International Journal of Cosmetic Science, 2016 Jul 4: 39(1):56-65, Molecular basis of retinol anti-aging properties in naturally aged human skin in vivo.

• Arch Dermatol, 2007;143(5):606-612, Improvement of naturally aged skin with vitamin A (retinol).

• Exp Dermatol, 1995;4(3):146-154, Ultrastructural effects of topical tretinoin on dermo-epidermal junction and papillary dermis in photodamaged skin. A controlled study.

• Journal of Cosmetic Dermatology, Mar 1, 2016, A comparative study of the effects of retinol and retinoic acid on histological, molecular, and clinical properties of human skin.

• Lancet, 2012;379(9813):361-372, Acne vulgaris.

• American Journal of Clinical Dermatology, 2008;9(6):369-381, Topical retinoids in acne vulgaris: update on efficacy and safety.

• Journal of investigative Dermatology, 1990 Jan;94(1): 132-138, Vitamin A Esterification in Human Epidermis: A Relation to Keratinocyte Differentiation.

• Journal of Drugs in Dermatology, 2015, 14(3):271-280, One-year topical stabilized retinol treatment improves photodamaged skin in a double-blind, vehicle-controlled trial.

• Journal of Drugs in Dermatology, 2015 Jan;14(1):24-30, A randomized, double-blind, split-face study comparing the efficacy and tolerability of three retinol-based products vs. three tretinoin-based products in subjects with moderate to severe facial photodamage.

• J Invest Dermatol, 1995;105(4):549-556, Application of retinol to human skin in vivo induces epidermal hyperplasia and cellular retinoid binding proteins characteristic of retinoic acid but without measurable retinoic acid levels or irritation.

• J Invest Dermatol, 2000;114(3):480-486, Vitamin A antagonizes decreased cell growth and elevated collagen-degrading matrix metalloproteinases and stimulates collagen accumulation in naturally aged human skin.