Vitamin C Capsules: Contract Manufacturing for Brands That Need Potency That Lasts
Vitamin C Capsules: Contract Manufacturing for Brands That Need Potency That Lasts

Vitamin C Capsules: Contract Manufacturing for Brands That Need Potency That Lasts

Payment Terms:

TT/LC/DP/PayPal/Western Union

Delivery Time:

3-4 weeks

MOQ:

2000 bottles

Category:

Capsules

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FDA
cGMP
ISO9001
ISO22000
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FSSC22000
HALAL
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REACH
DGM
DMF
ECOCERT
Eurofins
SGS

Product Description

Product Specifications

Parameter

Details

Active Ingredient

L-Ascorbic Acid, Sodium Ascorbate, Calcium Ascorbate, Ascorbyl Palmitate

Dosage Range

250mg – 1,000mg per capsule

Capsule Sizes

Size 00 (1,000mg), Size 0 (500mg), Size 1 (250mg)

Shell Options

Gelatin (bovine/porcine), HPMC (vegetarian), Pullulan (vegan)

Shelf Life

24–36 months (depends on formulation and packaging)

Production Capacity

1.6 million capsules/day

Certifications

FDA, GMP, ISO 9001/22000, FSSC 22000, HALAL, REACH, ECOCERT

Vitamin C Forms: Which One Fits Your Brand?

Vitamin C isn't just one ingredient. The form you choose affects cost, dose per serving, GI tolerance, and label positioning.

Form

Properties

Best For

L-Ascorbic Acid

Standard form, water-soluble, most cost-effective, acidic pH (~2.5)

Immune support, antioxidant positioning, high-dose formulas (500-1,000mg)

Sodium Ascorbate

Buffered, pH-neutral, lower GI irritation, contains small amount of sodium

Sensitive stomach formulas, electrolyte stacks, 2,000mg+ daily dosing

Calcium Ascorbate

Buffered, delivers elemental calcium alongside vitamin C

Women's health, bone support formulas where calcium is a secondary benefit

Ascorbyl Palmitate

Fat-soluble ester, used primarily for antioxidant properties

Beauty/collagen formulas, mixed antioxidant capsule blends

Vitamin C + Bioflavonoids

Ascorbic acid combined with citrus bioflavonoids (hesperidin, rutin, quercetin)

Enhanced absorption positioning, traditional immune wellness formulas

Most brands start with ascorbic acid — it's cost-effective and widely recognized by consumers. If your target audience takes high doses daily or has sensitive digestion, buffered forms reduce GI complaints, which translates to fewer returns and better reviews.

Why Most Vitamin C Capsules Fail Early

The formula on paper says "500mg vitamin C." But what arrives on the shelf may contain significantly less. Here's where potency gets lost:

1. Moisture absorption during production

Ascorbic acid starts absorbing water the moment it's exposed to ambient air. If your blending environment runs at 55-65% relative humidity, the active ingredient begins degrading before it even enters the capsule. We maintain production rooms at ≤45% RH year-round.

2. Shell moisture migration

Standard gelatin capsules contain 13-16% moisture by weight. Over time, that moisture migrates into the fill — and for a hygroscopic ingredient like ascorbic acid, this is a slow degradation trigger. HPMC capsules contain only 3-8% moisture, significantly reducing this risk.

3. Oxidation during storage and shipping

Vitamin C degrades when exposed to oxygen, light, and heat. Without proper packaging — amber bottles, desiccant packets, foil-sealed blister packs — potency drops quickly, especially during international shipping or in tropical climates.

The result: A capsule that starts at 500mg may test at 380-420mg after 6 months if moisture and oxidation aren't controlled. That's a label compliance failure — and a brand reputation problem.

Our Moisture Control Protocol

This is where 28 years of manufacturing experience shows:

Production Stage

Industry Standard

Runxin Approach

Blending Environment

Ambient RH (50-65%)

Controlled ≤45% RH

Capsule Shell Selection

Gelatin (default, cheapest)

HPMC recommended for vitamin C fills

Filling Process

Standard cycle time

Minimized air exposure; rapid seal after fill

Packaging

Basic HDPE bottle

Amber HDPE + silica desiccant + induction seal

Warehouse Storage

Room temperature

≤25°C, ≤50% RH, monitored continuously

Stability Testing

End-of-shelf-life check

Accelerated stability (40°C/75% RH/12 weeks) + real-time

We track potency retention across accelerated stability studies on every new formulation. Capsules produced under this protocol consistently retain ≥95% of labeled potency through the end of declared shelf life.

Customization Options

Dosage: 250mg / 500mg / 1,000mg per capsule — custom strengths on request

Release Profile: Immediate release or sustained/timed release (4-8 hours gradual release using beadlet technology)

Shell Material: Gelatin, HPMC (vegetarian), Pullulan (vegan-certifiable)

Combination Formulas:

  • Vitamin C + Zinc (immune support)
  • Vitamin C + Rose Hip (traditional antioxidant)
  • Vitamin C + Citrus Bioflavonoids (enhanced absorption)
  • Vitamin C + Elderberry Extract (seasonal wellness)
  • Vitamin C + Echinacea (immune defense)

Packaging: Bulk, HDPE bottles, blister packs, sachets, custom retail-ready packaging

Labeling Compliance: Regulatory review for US (FDA DSHEA), EU, Australia, and other target markets included

Production Process

  1. Formulation & Bench Samples: We develop your formula, produce bench-scale samples, and validate potency before any production commitment.
  2. Moisture-Controlled Blending: All active ingredient handling occurs in humidity-controlled rooms (≤45% RH).
  3. Capsule Filling: High-speed filling with minimized air exposure. In-process weight checks run every 15 minutes.
  4. Quality Testing: Identity, potency, microbial limits, heavy metals — tested in-house and verified by accredited third-party laboratories.
  5. Packaging: Desiccant insertion, induction sealing, and moisture-barrier packaging as standard for all vitamin C products.
  6. Stability Verification: Accelerated stability testing confirms shelf-life claims before any batch is released for shipment.

Quality Certifications

Runxin's vitamin C capsule production meets international regulatory requirements across multiple markets:

  • FDA Registered — US market compliance
  • GMP Certified — Good Manufacturing Practices
  • ISO 9001 / ISO 22000 — Quality management and food safety
  • FSSC 22000 — Food safety system certification
  • HALAL — Suitable for Muslim markets
  • REACH / ECOCERT — EU chemical safety and organic certification

Every batch ships with a Certificate of Analysis (COA) from accredited third-party testing.

Frequently Asked Questions

Q: Why do vitamin C capsules lose potency over time?

Ascorbic acid is highly hygroscopic — it absorbs moisture from the air and from the capsule shell itself. Moisture triggers oxidation, which breaks down the active ingredient. The solution is moisture-controlled production environments, low-moisture capsule shells (HPMC over gelatin), and proper packaging with desiccants and moisture barriers.

Q: Can you make sustained-release vitamin C capsules?

Yes. We offer timed-release formulations using beadlet technology that gradually releases vitamin C over 4-8 hours. This matches the body's absorption capacity better than a single bolus dose, since the body can only absorb a limited amount of vitamin C at one time. Sustained release is a strong positioning differentiator for premium brands.

Q: What's the practical difference between ascorbic acid and sodium ascorbate?

Ascorbic acid is acidic (pH ~2.5) and can cause stomach discomfort at doses above 1,000mg. Sodium ascorbate is pH-neutral and significantly better tolerated for daily high-dose use. Both deliver vitamin C effectively, but sodium ascorbate is the preferred choice for sensitive-stomach positioning or formulas targeting 2,000mg+ daily intake.

Q: How do you ensure the label claim is accurate throughout shelf life?

We use overage calculations — adding slightly more active ingredient at production to account for expected degradation over time. Every batch is tested for potency by accredited third-party laboratories. A Certificate of Analysis ships with every order, verifying that the minimum label claim is met at production and remains within specification through declared shelf life.

Q: What's the minimum order quantity?

MOQ varies by capsule size, formulation complexity, and packaging configuration. Contact us with your specifications and we'll provide a detailed quote within 24 hours.

Q: How long does production take?

Sample development takes 5-7 business days. Mass production typically takes 15-25 business days, depending on order volume and packaging complexity. Reorders are faster once the formula and packaging are approved.

Ready to Discuss Your Vitamin C Capsule Project?

Whether you're launching a new immune support line or reformulating an existing product that's struggling with stability, our team can help. Contact us with your target dosage, shell preference, and market — we'll respond within 24 hours with a formulation recommendation and timeline.

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FAQ

Q

Can you customize product formulations based on cross-border market demands?

A

Absolutely, we can tailor product formulations to meet local consumer preferences and regulatory requirements in your target markets.

Q

Can you provide multilingual labeling and instructions for cross-border products?

A

Certainly, we offer multilingual labeling and instructions to ensure accurate communication of product information in different countries' markets.

Q

What is the MOQ for cross-border business?

A

Our cross-border business MOQ is low, typically ranging from 1000 to 5000 units of products, and can be flexibly adjusted based on specific circumstances.

Q

Can you directly ship to overseas warehouses or facilitate split shipments?

A

We support direct delivery to overseas warehouses and can arrange split shipments according to your needs. We have well-established global logistics solutions.

Q

Do you support commonly used payment methods for cross-border markets?

A

Yes, we support widely used cross-border payment settlement methods such as PayPal, credit cards, and TT bank transfers.

Q

Can you provide import customs clearance documents for major countries?

A

Yes, we can provide customs registration information, inspection reports, and other customs clearance documents for different countries.

Q

Does your product packaging design comply with regulatory requirements in major countries?

A

Our product packaging design can be adjusted to meet the regulatory standards and requirements of different countries, ensuring compliance with local norms. 

Q

Can you conduct small-scale production for cross-border testing?

A

Certainly,we welcome small-scale trial orders. We have dedicated small-scale production lines available for cross-border market testing,assisting you in evaluating market potential and feedback.