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Pigmentation
Obagi

Vitamin C Serum 20% (C25 Serum NEO)

High-concentration pure vitamin C targeting dark spots & dullness

Category
Serum
Price
¥5,000〜¥8,000
Rating
4.6/5
全肌質対応特にシミ・くすみ悩み

Key Ingredients

L-アスコルビン酸(ピュアビタミンC) 20%
Directly inhibits tyrosinase, the rate-limiting enzyme in melanogenesis. Reduces oxidized melanin to lighten dark spots.
ビタミンE(トコフェロール)
Synergistic antioxidant effect with Vitamin C. Vitamin C regenerates vitamin E radicals.

How It Works

L-ascorbic acid binds to the active site of copper-dependent tyrosinase, inhibiting DOPA→DOPAquinone oxidation (rate-limiting step of melanogenesis). Also reduces existing melanin quinone structures (DOPAquinone→DOPA), shifting dark eumelanin toward pheomelanin. Neutralizes UV-induced free radicals and serves as a cofactor for prolyl hydroxylase in collagen synthesis. 20% concentration optimizes transdermal absorption at pH 2.5-3.5.

How to Use

Apply 3-4 drops after cleansing and toner, AM or PM. If using in AM, always layer SPF50+ sunscreen. Can combine with retinol but start by alternating.

Expected Results

Reduced dullness and brighter skin tone at 2-4 weeks. Visible lightening of pigmentation at 4-8 weeks. Significant reduction in spot size and intensity after 12+ weeks. Improved firmness and elasticity.

Scientific Evidence

Pullar JM, Carr AC, Vissers MCM (2017)
The roles of vitamin C in skin health. NutrientsDOI: 10.3390/nu9080866
ビタミンCの皮膚における多面的役割(抗酸化・コラーゲン合成・メラニン抑制)を包括的にレビュー。外用の有効性を確認。
Pinnell SR, Yang H, Omar M, et al. (2001)
Topical L-ascorbic acid: percutaneous absorption studies. Dermatol Surg
L-アスコルビン酸の経皮吸収はpH 3.5以下で最大化。20%濃度が飽和吸収量として最適であることを実証。
Traikovich SS (1999)
Use of topical ascorbic acid and its effects on photodamaged skin topography. Arch Otolaryngol Head Neck Surg
10%ビタミンCの3ヶ月外用で光老化による色素沈着・シワが有意に改善。プラセボとの二重盲検試験。

Precautions

L-ascorbic acid is unstable to light, heat, and air — store in cool dark place and use within 2-3 months. Discard if color changes to brown (oxidation). Low pH may cause initial tingling. Sensitive skin should start at 10%.

Related Professional Treatments

Professional treatments that pair well with this home care product.

Photofacial Picosure

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■ Disclaimer
Information on this page is based on scientific literature and does not guarantee product results. Effects vary by individual. Discontinue use and consult a dermatologist if skin issues occur.