Vitamin C at 20% L-Ascorbic Acid is as potent as topical Vitamin C gets. L-Ascorbic Acid is the most bioavailable and most clinically proven form of Vitamin C for topical use, and 20% is the maximum concentration at which it is formulated for daily use by normal and oily skin types that can tolerate this level of activity. It is not a gentle introduction. It is maximum antioxidant protection, maximum brightening activity and maximum collagen support in a single daily morning serum.Obagi Professional-C Serum 20% defends against free radical damage from UV rays, blue light and infrared radiation, brightens and evens skin tone through L-Ascorbic Acid's tyrosinase inhibition and antioxidant mechanisms, supports collagen and elastin synthesis and reduces the appearance of fine lines and dark spots. Sodium Hyaluronate provides hydration alongside the high-concentration Vitamin C without making the formula heavy on oily skin types.Who Is It For? Normal to oily skin wanting maximum-strength daily Vitamin C antioxidant protection Significant dullness, sun damage, dark spots and uneven skin tone wanting the most potent Vitamin C available Those on GLP-1 medications wanting maximum antioxidant protection during body composition changes Those progressing from the 15% concentration who are ready for maximum-strength daily Vitamin C Those who are not new to Vitamin C and whose skin can tolerate high-concentration L-Ascorbic Acid daily How Does It Work?L-Ascorbic Acid at 20% provides maximum antioxidant free radical neutralisation against UV-induced, blue light-induced and infrared-induced reactive oxygen species. It inhibits tyrosinase to reduce melanin synthesis and progressively brighten existing pigmentation. It acts as an essential cofactor in collagen hydroxylation, supporting structural protein production in the dermis. At 20%, the antioxidant and brightening mechanisms operate at their highest topically achievable potency.Key Ingredients L-Ascorbic Acid 20%: Maximum-strength, most bioavailable form of Vitamin C. Neutralises free radicals, inhibits tyrosinase for brightening, supports collagen synthesis and defends against UV, blue light and infrared oxidative stress. Use within 3 to 6 months of opening and store in a cool dark place to preserve potency. Sodium Hyaluronate: Provides hydrating support alongside the high-concentration Vitamin C to maintain skin comfort during maximum-strength daily antioxidant use. Benefits Maximum daily antioxidant protection against UV, blue light and infrared free radicals Brightens skin and reduces dark spots through tyrosinase inhibition Supports collagen and elastin production Sodium Hyaluronate hydration alongside Vitamin C Fast-absorbing, lightweight formula with no greasy residue What Results Can You Expect?At 4 weeks: improved skin radiance, brighter complexion and early dark spot fading with consistent daily morning use. At 8 to 12 weeks: significant improvement in skin tone, dark spots and overall radiance. Long-term: comprehensive progressive brightening and antioxidant protection from daily maximum-concentration L-Ascorbic Acid use.How We Use It at Face for SoulAs a pharmacist prescriber specialising in skin health, Professional-C 20% is the morning antioxidant step I recommend for patients with oily skin who want maximum brightening and antioxidant activity and whose skin can tolerate 20% L-Ascorbic Acid without irritation. For drier or more sensitive skin, 15% or 10% is more appropriate. Use within 3 to 6 months once opened and store properly to maintain potency.How to UseApply 5 to 7 drops to clean skin on the face, neck and chest each morning before moisturiser and SPF. Use within 3 to 6 months of opening. Store in a cool, dark place. Follow with Obagi Hydrate or Hydrate Light and Obagi Sun Shield SPF 50 every morning.Frequently Asked QuestionsShould I start at 20% or a lower concentration?If new to Vitamin C or if you have sensitive or dry skin, start at 10%. If you have been using Vitamin C regularly and have oily or normal skin, 20% is appropriate. Your skin should tolerate it without stinging or significant irritation. If it does not, step down to 15%.Can I use it with tretinoin?Yes. Use Professional-C 20% in the morning. Apply tretinoin in the evening only. Do not use on the same evening.Is it pregnancy safe?L-Ascorbic Acid has no established pregnancy contraindications. Always consult your midwife or obstetrician before starting new skincare during pregnancy.Is it suitable for rosacea-prone skin?20% L-Ascorbic Acid may be too stimulating for rosacea-prone skin. Start with 10% or 15% and assess tolerance. Contact us for guidance.Does it clog pores?No. Non-comedogenic.Clinical InsightAs a pharmacist prescriber, Professional-C 20% is the morning antioxidant step that provides the most comprehensive daily UV and environmental free radical protection available topically for oily and normal skin that can tolerate maximum-strength L-Ascorbic Acid. For patients investing in significant anti-ageing programmes, protecting against daily environmental oxidative damage at the highest level available is the step that preserves everything else.Research and EvidenceL-Ascorbic Acid's antioxidant, tyrosinase-inhibiting and collagen synthesis-supporting mechanisms are among the most extensively published in dermatological literature. Published comparative research confirms L-Ascorbic Acid as the most bioavailable topical form of Vitamin C with superior efficacy to stabilised derivatives at equivalent concentrations.How Does It Compare?Professional-C Serum 20% vs Professional-C Serum 15%: 20% provides maximum antioxidant and brightening activity. 15% provides strong activity with better tolerance for normal to dry skin. 20% is appropriate when tolerance to 15% is well established and the patient wants maximum concentration.Professional-C Serum 20% vs Obagi Professional-C Microdermabrasion Polish and Mask: The Polish and Mask delivers 30% L-Ascorbic Acid in a rinse-off treatment format for intensive 2 to 3 times per week use. Professional-C 20% is a daily morning leave-on serum. Different formats, different use patterns, both appropriate within the same programme.Complete Your RoutineMorning: Obagi cleanser, Obagi Professional-C Serum 20%, Obagi Hydrate Light or Hydrate, Obagi Sun Shield SPF 50.Why Buy From Face for Soul?At Face for Soul, Professional-C 20% is the maximum daily antioxidant serum for patients with normal to oily skin wanting the most potent morning Vitamin C protection available. Contact us if you have questions about which Professional-C concentration is most appropriate for your skin type.
