Thorne Vitamin D-1,000 Review 2026: Review
It's actually fine. — Legitimate
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"Third-party tested for purity and contaminants"
Thorne supplements are NSF Certified and regularly tested; claim is verifiable and accurate.
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"Vitamin D3 is more potent and better absorbed than D2"
D3 has superior bioavailability and raises serum 25(OH)D more effectively than D2.
PubMed: D3 vs D2 bioavailability meta-analysis -
"1,000 IU daily supports bone health and corrects deficiency"
Clinical deficiency correction requires 2,000-4,000 IU daily; 1,000 IU is maintenance only.
PubMed: Vitamin D3 clinical dosing guidelines
Consumer advice
If you're deficient in vitamin D (confirmed by blood test), this product alone won't correct it—you'd need a higher dose (2,000-4,000 IU+) or medical supervision. This is best used as a maintenance supplement if you already have adequate levels or as part of a broader supplementation plan. The product is high-quality and transparent, so the main decision is whether the dose matches your actual need. Consider getting a vitamin D test first (the clinic even offers one for $89) to determine if you need this at all.
Claims vs Evidence
MODEST2 of 5 claims supported by evidence.
"Supports healthy teeth and bones"
Supported
Vitamin D essential for calcium absorption and bone health; clinical evidence solid
Based on: Vitamin D3
"Promotes lean muscle mass and helps maintain muscle strength"
Partial
Vitamin D supports muscle function; benefits strongest in deficient individuals, modest in replete
Based on: Vitamin D3
"Enhances the absorption and retention of calcium"
Supported
Vitamin D3 is essential for intestinal calcium absorption; well-established mechanism
Based on: Vitamin D3
"Supports healthy brain function"
Partial
Vitamin D receptors in brain; cognitive benefits mainly in deficient populations
Based on: Vitamin D3
"Promotes cardiovascular health and immune function"
Partial
Vitamin D modulates immunity and vascular function; benefits inconsistent in sufficient individuals
Based on: Vitamin D3
2 supported · 3 partial
Ingredients
Based on peer-reviewed research from PubMed and Examine.com
Essential fat-soluble vitamin. Supports bone health, immune function, and may improve exercise tolerance in deficient individuals.
Research-backed dose: 400–80,000 IU daily depending on condition and deficiency status
In this product: 1,000 IU per capsule (underdosed)
Hypromellose Capsule
Amino acid found in collagen. Used as a stabilizer in drugs and lab tools. No solid evidence as a standalone supplement.
Research-backed dose: No established dose from provided studies
In this product: Dose not disclosed
Leucine
Amino acids found in protein-rich foods. Evidence for direct performance benefits is weak and inconsistent.
Research-backed dose: No established dose (insufficient research data)
In this product: Dose not disclosed
Vitamin E (as d-Alpha Tocopheryl)
Fat-soluble antioxidant vitamin with evidence for immune support, UTI prevention, and skin recovery.
Research-backed dose: 100-400 IU daily based on study doses
In this product: Dose not disclosed
Price & Value
FairThorne Vitamin D-1,000
$25.00
Nature Made Vitamin D3 1000 IU or NOW Foods Vitamin D-1000
$8-12 for 100 capsules (~$0.08-0.12 per capsule)
Signals
- Shows actual ingredient doses
Research sources: PubMed · Examine.com
Analyzed product: https://myeye2eye.com/products/vitamin-d-1-000
Analysis generated: 2026-05-02 · Engine v1.0.0