COS DE BAHA Vitamin C Serum 30ml

Values: 100% Genuine (Adilsons policy) · FA-Safe · Fragrance-Free (confirmed via INCI) · Vegan-Friendly* / Cruelty-Free* (brand-stated).

Pros: real brand-stated 15% concentration of the most evidence-backed Vitamin C form, includes arbutin for additional pigment support, good value per independent reviews. Caveats: L-ascorbic acid at this strength is genuinely irritating for some users (Adilsons' own existing product copy already warns of this); multiple independent reviewers report the product oxidizing (turning orange/brown) either on arrival or with use — see the Stability section for how to judge this.

Classification: RED — not for under 16. 15% L-Ascorbic Acid is a clinical-grade, low-pH active that can cause meaningful irritation even in adults with no barrier issues; prepubescent and early-teen skin has no functional need for antioxidant/anti-aging correction and has a less-developed barrier that makes this strength a poor first exposure to actives.

Step 1 (When): AM, ideally, though PM works too. Step 2 (How much): 2-3 drops. Step 3 (How): apply to dry or lightly damp skin, wait 10-15 minutes before moisturizer if you're new to it.

Introduce this as the ONLY new product in your routine. Wait a full 14 days before adding anything else. This isolation window ensures you can identify whether any reaction is caused by this specific product.

1. Cleanse. 2. Toner (optional). 3. COS DE BAHA Vitamin C Serum — 2-3 drops on dry skin, wait 10-15 minutes if sensitive. 4. Moisturizer. 5. Sunscreen SPF50+ PA++++ (mandatory — Vitamin C and SPF work together against UV-driven free radical damage, and this serum does not replace sunscreen).

1. Double cleanse if wearing SPF/makeup. 2. Toner (optional). 3. COS DE BAHA Vitamin C Serum, only if not also running an acid or retinol that night. 4. Moisturizer. Most people find AM more logical for this product since Vitamin C's antioxidant/pollution-defense role is most relevant during daytime UV exposure.

Technique: pat/press, do not rub. Skin state: dry skin is best — L-ascorbic acid works at a specific low pH, and applying to very wet skin dilutes it. Wait time: 10-15 minutes before moisturizer for beginners; more tolerant users can reduce this to 1-3 minutes. Hands deliver 100% of product; cotton pads absorb approximately 30-40% — use hands.

This is an encyclopedia map of all product types. You do not use all of these daily. You select modules based on your skin state.

Global rules: viscosity ladder thinnest to thickest, water-phase before oil-phase, pH-dependent acids need time at target pH before layering. If the routine pills, stings, or feels heavy, reduce layers, not increase.

AM Maximum Stack: 1. Rinse/gentle cleanse (optional). 2. pH-prep toner (optional). 3. Hydrating toner layers (optional). 4. Essence (optional). 5. Booster/soothing serum (optional). 6. Antioxidant lane, Option A — this product (best on dry skin, wait 1-3 minutes before next step). 7. Pigment support lane (optional — this product's arbutin already covers some of this). 8. Hydration serum lane (optional). 9. Oil-control lane (optional). 10. Moisturizer. 11. Sunscreen SPF50+ PA++++ (non-negotiable).

PM Maximum Stack: 1. Micellar pre-cleanse (optional). 2. Oil cleanser if wearing SPF/makeup. 3. Water cleanser. 4. pH-prep toner (optional). 5. Soothing serum (optional). 6. Anchor product — this Vitamin C Serum, only if not running a retinol or acid the same night. 7. Moisturizer. Do not layer retinoids with AHA/BHA/LAA Vitamin C in the same night; keep one lane per night.

Lane strictness: Retinoid OR Exfoliation OR Strong Vitamin C (LAA) — this product — OR Acne-control active per routine; barrier/hydration can always accompany.

Rest days: most people can tolerate this daily once adjusted, but if it's your only active, no dedicated rest day is required; if paired with a retinol, keep them on separate nights as shown above. Overuse warning: applying more than once daily does NOT speed brightening — it increases irritation risk on already-photosensitive, low-pH-exposed skin.

Prerequisites: your routine MUST already include a daily SPF habit and a tolerated moisturizer before starting this. Without these foundations, this product causes more harm than benefit.

Barrier index gate: if your skin stings on moisturizer or shows visible flaking, repair first with SKIN1004 Centella Probio-Cica Enrich Cream before starting this.

Dullness and uneven tone: L-ascorbic acid inhibits tyrosinase (melanin production) and neutralizes free radicals that contribute to dull-looking skin. Collagen support: Vitamin C is a required cofactor for collagen synthesis. UV/pollution defense: as an antioxidant, it helps neutralize free radicals generated by unprotected sun and airborne particulate exposure. Secondary benefit: arbutin adds tyrosinase-inhibition support for pigment. What it cannot do: it cannot replace sunscreen, it cannot lighten your natural skin tone (only fades excess pigment), and it cannot repair already-oxidized product back to fresh.

Sunscreen (mandatory, works synergistically with Vitamin C against UV damage): primary — Beauty of Joseon Relief Sun: Rice + Probiotics SPF50+; alternatives — SKIN1004 Centella Hyalu-Cica Water-Fit Sun Serum, Anua Heartleaf Silky Moisture SunCream, ROUND LAB Birch Juice Tone-Up Sunscreen.

Barrier-support moisturizer: primary — SKIN1004 Centella Probio-Cica Enrich Cream; alternatives — Dr.Althea 147 Barrier Cream, Beauty of Joseon Dynasty Cream, Anua Birch Moisture Boosting Cream.

PM active pairing: COS DE BAHA Retinol Serum on separate nights is the classic complementary split (AM Vitamin C, PM retinol).

This is a conflict-solver for ACTIVE ingredients. If you run multiple actives, use these rules to avoid irritation, deactivation, and barrier damage.

Universal rules: run only one primary active lane per routine. If moisturizer stings or skin feels tight within 30 minutes of cleansing, pause all actives and run barrier-only for 3-7 days.

× Benzoyl Peroxide — never combine, oxidation destroys Vitamin C activity; run Vitamin C AM, BPO PM instead.

× Copper Peptides — separate; copper ions accelerate Vitamin C oxidation and low pH destabilizes peptides; run Vitamin C AM, copper peptides PM.

× AHAs/BHAs (separate products) — avoid layering (excess acidity → stinging and barrier irritation); if insisting, apply Vitamin C first, wait 15-20 minutes, then the acid — still higher risk than an AM/PM split.

× Retinoids — don't layer same routine; classic split is AM this Vitamin C Serum / PM retinol.

× High-% Niacinamide — generally compatible in modern formulas, but can trigger flushing in reactive skin; wait 10-15 minutes after Vitamin C before niacinamide, or split AM Vitamin C / PM niacinamide.

Scheduling template (AM/PM Split): AM this Vitamin C Serum → moisturizer → SPF. PM retinoid or acid lane → moisturizer. This is the most common, lowest-irritation-risk approach.

MYTH: "Vitamin C serum replaces sunscreen." REALITY: Vitamin C is an antioxidant that helps neutralize some UV-generated free radicals; it provides no measurable SPF and does not replace daily sunscreen.

MYTH: "A slightly yellow serum is always spoiled." REALITY: a very pale yellow tint can be normal for L-ascorbic acid; a shift to a distinctly darker yellow, orange, or brown is the actual oxidation warning sign — see the Stability section for the real threshold.

July-November sugar cane burning season increases airborne PM2.5 in parts of Mauritius — this is exactly the kind of pollution exposure Vitamin C's antioxidant mechanism is meant to help defend against, making AM use particularly relevant during that period. Mauritius tap water hardness varies by region; hard-water residue can add to irritation from this low-pH active, so a pH-balancing toner beforehand is worth trying if stinging feels worse than expected.

Free Acid Value: pH not publicly disclosed. L-Ascorbic Acid formulas are typically formulated around pH 3-3.5 to keep the acid in its active form — not independently confirmed for this exact SKU, but consistent with how L-ascorbic acid serums generally need to be made to function.

Full INCI list: Propanediol, Aloe Barbadensis Leaf Extract, Ascorbic Acid, Arbutin, 1,2-Hexanediol, Arginine, Sodium Hyaluronate, Panthenol, Sodium Hydroxide, Camellia Sinensis Leaf Extract, Momordica Charantia Fruit Extract, Sambucus Nigra Flower Extract, Leontopodium Alpinum Extract, Disodium EDTA. [--- Estimated 1% Line ---] Estimated after Panthenol/Sodium Hydroxide — ingredients from Camellia Sinensis Leaf Extract onward are estimated (not brand-confirmed) to sit below 1%. Sodium Hydroxide here functions as a pH-adjuster for the acid, not a hazard at formulation levels.

Preservative system: 1,2-Hexanediol plus Disodium EDTA (chelating agent that also helps slow oxidation by binding trace metals that would otherwise accelerate it).

Fragrance status: Fragrance-Free (no Parfum/Fragrance listed). Scent: a faint characteristic "Vitamin C" tang is normal; a sour or off smell is a spoilage sign, not a scent trait. Intensity: estimated 1 out of 5. EU 26 allergen screen: none of the 26 named allergen molecules detected as standalone listings. Alcohol disclosure: Alcohol-Free.

Halal: *Self-assessed by Adilsons based on available INCI data. No ethanol, no porcine-derived ingredients, and no haram animal-derived ingredients detected in the declared list. This is NOT a formal Halal certification.

Vegan: *Self-assessed by Adilsons based on available INCI data. No animal-derived ingredients detected. This is NOT a formal vegan certification.

Cruelty-Free: *Brand-stated policy, not independently certified by Leaping Bunny, PETA, or equivalent audit.

Microplastic-Free: Yes.

MFDS Classification: not publicly confirmed. Clinical evidence: L-ascorbic acid has Strong, well-established published evidence for antioxidant defense, collagen synthesis support, and pigment-fading at effective concentrations (typically cited as 10-20%, which 15% falls within); no brand-run trial for this exact SKU was found. Evidence confidence: High for the ingredient class at this concentration range, Medium for this specific product's real-world stability given the oxidation reports.

Fungal Acne Safety: FA-Safe. No documented Malassezia-feeding esters among the confirmed ingredients.

Assessment: Low. No known pilling triggers among the confirmed ingredients; reduce layers if pilling occurs when stacked with a heavy sunscreen or silicone-based product.

Fresh color: clear to very pale yellow. Oxidation warning color: a shift to distinctly darker yellow, orange, or brown means the Vitamin C has oxidized and can generate free radicals instead of neutralizing them — this does not mean the ingredient is inherently ineffective, it means this specific batch/bottle is spent and should be discarded. Multiple independent reviewers reported exactly this kind of oxidation with this product, either on arrival or with use, so check color at every use. Storage: keep tightly capped, away from light and heat above roughly 25°C; store in a cool, dark spot rather than a sunny bathroom shelf. Spoilage signs: darkening color, an off/sour smell, or separation.

Patch test: inner forearm for 24 hours, then behind the ear for 24 hours, then begin facial use at low frequency. If adverse reaction: STOP ALL ACTIVES. For 72 hours, use ONLY gentle cleanser plus plain moisturizer plus mineral SPF — no acids, retinoids, Vitamin C, exfoliants, or essential oils. After 72 hours, reintroduce ONE product per 14 days. Emergency stop signals: hives, swelling, blistering, persistent burning, or breathing difficulty — seek emergency care.

1. Not checking the serum's color before each use. 2. Storing the bottle on a sunny windowsill or in a hot car. 3. Layering with benzoyl peroxide or a separate strong acid the same routine. 4. Skipping the patch test at this strength. 5. Expecting it to replace sunscreen rather than complement it.

Volume: 30ml. Amount per use: 2-3 drops (~0.4-0.6ml). Approximate uses per container: roughly 50-70 applications if used before it oxidizes. Lifespan: at once-daily AM use, approximately 7-9 weeks, though L-ascorbic acid's real usable lifespan often depends more on oxidation speed than on how much is left in the bottle — discard on schedule if the color shifts before you finish it. Reorder roughly 2 weeks before you expect to run out, and consider buying a size you can finish within about 2-3 months of opening.

This serum's job is AM-focused antioxidant/pigment defense — it is the Vitamin C (LAA) lane anchor, never combined same-routine with BPO, copper peptides, or a separate strong acid. AM: cleanse → toner (optional) → Vitamin C Serum on dry skin → moisturizer → sunscreen. PM (if not used AM): cleanse → Vitamin C Serum → moisturizer, kept off retinol/acid nights.

If your skin is barrier-compromised right now: repair first before starting or resuming this. If you run a retinol at night: keep this Vitamin C serum in AM for the classic, lowest-irritation split. If the serum has darkened in color: stop using it and replace — oxidized Vitamin C works against you, not for you.

After purchasing, you will receive our skincare education email series covering this product in depth. The recommendations above are based on formulation synergy with COS DE BAHA Vitamin C Serum, not on margin or stock levels. If a pairing does not exist in our catalog, we say so. If you already own a product that fills the same role, use what you have first.

If L-ascorbic acid's low pH or oxidation-sensitivity is a dealbreaker, COS DE BAHA Tranexamic Serum is a real, in-stock alternative from the same brand offering a different, more pH-neutral brightening pathway (Tranexamic Acid 5% + Niacinamide 5%) with less oxidation risk.

Choose this Vitamin C Serum over the Tranexamic Serum if you specifically want L-ascorbic acid's antioxidant/collagen-support mechanism, not just pigment-fading.

Upgrade triggers: you want antioxidant/pollution defense specifically, not just pigment-fading; you can commit to careful storage and checking color each use; you don't have reactive/sensitized skin right now. Do not upgrade yet if: your barrier is currently compromised; you've reacted to acids before; you can't reliably store the bottle away from heat/light.

If you match 2 or more upgrade triggers above, this Vitamin C Serum is worth choosing. If not, the Tranexamic Serum is sufficient and gentler. Consistency beats complexity.

This product's PRIMARY function is: L-ascorbic acid antioxidant and pigment-fading support. You do NOT need this if you already own another L-ascorbic acid Vitamin C serum — finish that one first, and check its color before assuming it's still good. Stacking assessment: No Benefit (same mechanism, plus oxidation risk to both) if run alongside another LAA Vitamin C product; Significant Benefit if your current routine has no dedicated antioxidant/pigment lane.

This product is sourced through authorized Korean distributors — primarily Craver Co., Ltd (South Korea), alongside other verified distribution partners. Craver is a major Korean beauty distributor and the parent company of SKIN1004, handling authorized distribution for multiple K-beauty brands. All products are shipped directly to Mauritius via verified channels.

For comprehensive information about how we verify authenticity, our layered verification system, and how to check your product at home, visit our dedicated Authenticity and Trust page. Given that oxidation can happen in transit for any L-ascorbic acid product regardless of authenticity, check the color on arrival and report any concerns rather than assuming it means a counterfeit.

Parent Company: JAINA Co., Ltd (CEO Junwon Lee). Founded: 2019. Headquarters: Suwon, South Korea. Manufacturing: contract manufacturing in South Korean laboratories the brand states are MFDS-certified.

COS DE BAHA positions itself as a value/high-potency actives brand, selling clearly-labeled single- and combo-active serums at accessible prices relative to prestige K-beauty actives brands. This Vitamin C serum sits alongside the brand's Tranexamic Serum as its two main brightening options, at different mechanisms and stability profiles.

Independent reviews for this exact product are mixed but generally positive on core function: many praised the packaging quality, brightening effect, evened tone, reduced pigmentation, and affordability. The most consistent complaint theme was oxidation — several users reported the serum turning orange/brown either shortly after opening or with continued use, which is a known characteristic risk of L-ascorbic acid formulas generally rather than necessarily a defect unique to this product.

Why did my serum turn orange? That's oxidation — L-ascorbic acid degrades on exposure to light, air, and heat. It's a known characteristic risk of this Vitamin C form; discard and replace rather than continuing to use it.

Can I use this with retinol? Not the same routine — use the AM Vitamin C / PM retinol split.

Will this cause breakouts? It's a documented possible side effect at this strength, per both the brand's positioning and Adilsons' own prior product notes — patch test and introduce slowly.

How do I store it to avoid oxidation? Keep it tightly capped, away from direct light and heat, ideally somewhere cooler than a bathroom shelf.

Does this replace sunscreen? No — it's a complementary antioxidant, not a UV filter.

L-Ascorbic Acid

The pure, most bioactive form of Vitamin C, effective but less stable than derivative forms.

Oxidation

A chemical reaction with oxygen that degrades L-ascorbic acid, visible as a color shift toward orange/brown.

Free radical

An unstable molecule that can damage skin cells; antioxidants like Vitamin C help neutralize them.

Tyrosinase

The enzyme that produces melanin (pigment) in skin.

Chelating agent

An ingredient (like Disodium EDTA) that binds trace metals to help slow oxidation and support preservative function.

Every product sold by Adilsons Beauty is 100% genuine, sourced through authorized Korean distribution channels. Full details on our verification system: Authenticity and Trust.

Our team is available to help you build a routine, troubleshoot reactions, and answer ingredient questions. WhatsApp: +230 5 778 2336.

For in-depth skincare education, visit our blog at adilsons.mu/blogs/k-beauty or subscribe to our email to get our guided education series delivered to your inbox.

Coverage: Island-wide delivery (Mauritius).

Processing and Timing: Orders process in 1-2 business days; usually ready by Day 3 for pickup by our delivery partners/regional team. Partner collection can take up to 1 week. After pickup, delivery typically takes 1-5 business days (weekdays only).

Express: May be available by region; request on WhatsApp: +230 5 778 2336.

Liquids/Sensitive Items: Serums, toners, liquid makeup (and kits containing liquids) are pickup or door-to-door only; checkout enforces this.

Scheduling: Deliveries run by region on set schedules; we will contact you the evening before.

Pickup: Citadelle Mall pickup available.

Returns: No change-of-mind exchanges.

Refunds (Summary): For defective/damaged on receipt (report within 48h), wrong item, or manufacturing defect within 6 months. Refunds via bank transfer (7-10 business days); card refunds may incur a 5% processor fee (fee not charged for defects/order errors). Opened skincare/personal-care items are non-returnable (except if damaged on delivery).

Source of Truth: This is a quick snapshot. If anything differs, the policy pages are final.

Store Policies: For the most up-to-date information, please review our Shipping Policy and Refund Policy.

Best for: non-sensitive, acid-tolerant users age 16+ who already have a daily SPF habit and want real antioxidant, collagen-support, and pigment-fading benefits from L-ascorbic acid specifically. Key benefits: real brand-stated 15% concentration, arbutin adds extra pigment support, good independent value/brightening reviews. Keep in mind: genuinely irritating for some at this strength; oxidation is a documented real risk — check color before every use and store carefully.

Assessment: Consult Oncologist. While fragrance-free and retinoid-free, this is a 15% low-pH acid-strength active that may be too stimulating for treatment-sensitized skin without your care team's input. Consult your oncology care team before introducing any new active skincare products during treatment.

Quick scanner: Week 1-2 — introduce alone every other day, monitor for stinging or breakouts. Week 3-4 — increase to daily if stable. Week 5+ — add one support product only if genuinely needed. If irritation occurs at any point, follow the 72-Hour Barrier Reset above.

This product must be introduced as the ONLY new product. Wait 14 days before adding anything else.

Antioxidant pollution defense: L-Ascorbic Acid is one of the most-studied topical antioxidants for neutralizing free radicals generated by UV exposure and airborne pollution — directly relevant during Mauritius's July-November sugar cane burning season when PM2.5 levels rise, making AM application (alongside SPF) especially useful in that window.