Doctor's Best Niacin Sustained-Release with niaXtend, 500 mg, 120 Tablets supplement bottle
Doctor's Best

Niacin Sustained-Release with niaXtend, 500 mg, 120 Tablets

What We Researched
1 active ingredient analyzed · 4 inactive ingredients decoded · 1 brand certification checked · 3 retailers compared · Last updated: Mar 2026
93
Product Score Excellent
61
Brand Score Fair

Product Analysis

Transparency Excellent

Supplement Facts

IngredientAmount% DV
Niacin (as nicotinic acid) 500 mg 3,125%
Bioavailability Excellent

Absorption Rating

  • Niacin (as nicotinic acid) Good
Other Ingredients Excellent

Fillers & Additives

  • Vegetable waxes (rice bran and/or carnauba wax)
  • Stearic Acid
  • Magnesium Stearate (Vegetable Source)
  • Silica
Efficacy Very Good

Dosage Analysis

  • Niacin (as nicotinic acid) 500 mg High

Supplement Facts

Ingredient Amount % Daily Value
Niacin (as nicotinic acid) 500 mg 3,125%

Other Ingredients

Inactive ingredients used in manufacturing. All rated for safety.

Vegetable waxes (rice bran and/or carnauba wax) Unknown
Stearic Acid Safe

Helps ingredients flow smoothly through manufacturing equipment.

Magnesium Stearate (Vegetable Source) Generally_safe

It is used to prevent ingredients from sticking to manufacturing equipment.

Silica Safe

Prevents ingredients from clumping and improves powder flow.

Price Comparison

Price History

Tracked across major retailers. Updated periodically.

$20$19$18$17$16 Mar 12 $17.99
Vitacost

Prices shown at time of last check. Click a retailer to see current price. GoodSupp is not affiliated with any retailer.

Brand Trust Report
Doctor's Best

Founded 1990 · Tustin, California, USA · 186 products · doctorsbest.com

Certifications

1 certification
Fda Gmp Inspections Verified Source

Transparency

2 claims
Third Party Testing Claim — Claimed Source

Violation History

1 incident
Recall Red Yeast Rice2014-06-26Source
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Frequently Asked Questions
Is Doctor's Best Niacin Sustained-Release with niaXtend, 500 mg a good supplement?

Doctor's Best Niacin Sustained-Release with niaXtend, 500 mg, 120 Tablets received a product quality score of 93/100 in GoodSupp's independent analysis, placing it in the top tier of supplements we've analyzed. The product contains 1 active ingredients with 120 servings per container. Of the 4 inactive ingredients, 2 are rated safe and 0 are flagged for review. The manufacturer, Doctor's Best, holds a brand trust score of 61/100 with 1 verified certifications including Fda Gmp Inspections.

What are the ingredients in Doctor's Best Niacin Sustained-Release with niaXtend, 500 mg?

Doctor's Best Niacin Sustained-Release with niaXtend, 500 mg contains 1 active ingredients: Niacin (as nicotinic acid) (500 mg). Notable high-dose ingredients include Niacin at 3,125% DV. Each ingredient's dosage, form, and safety rating is analyzed independently in GoodSupp's full product breakdown.

Is Doctor's Best Niacin Sustained-Release with niaXtend, 500 mg safe to take?

Doctor's Best Niacin Sustained-Release with niaXtend, 500 mg, 120 Tablets has been analyzed for ingredient safety across all its components. Always consult your healthcare provider before starting any new supplement, especially if you take medications or have underlying health conditions.

Is Doctor's Best a trustworthy supplement brand?

Doctor's Best receives a brand trust score of 61/100 based on GoodSupp's independent analysis of certifications, regulatory history, and transparency practices. Founded in 1990 and headquartered in Tustin, California, USA, the company offers 186 products in their lineup. They hold 1 verified certifications including Fda Gmp Inspections. Third-party certifications are independently verified and indicate the brand meets specific quality, purity, and manufacturing standards. Note: Doctor's Best has 1 historical regulatory incident on record, which are factored into the trust score.

How much vitamin d3 should i take daily?

The optimal dosage depends on your individual health needs, age, sex, and current nutrient levels. Recommended daily amounts are established by health authorities but may vary from therapeutic doses used in clinical research. It's important to check the Supplement Facts label for the exact amount per serving and compare it against the % Daily Value. Some supplements provide mega-doses well above the Daily Value, which may not be necessary and in some cases could be harmful — particularly for fat-soluble vitamins (A, D, E, K) that accumulate in the body. GoodSupp's efficacy analysis evaluates whether a product's dosages align with clinically studied amounts. Always consult your healthcare provider for personalized dosage recommendations.

What does vitamin d do?

This is an important question for supplement consumers. The dietary supplement industry is largely self-regulated, which means product quality, ingredient transparency, and safety practices vary significantly between brands and products. The most reliable way to evaluate any supplement is to check for third-party testing certifications, review the full ingredient list and dosages, and research the brand's regulatory track record. GoodSupp's database of over 250,000 analyzed products provides independent quality scores, ingredient safety ratings, and brand trust reports to help you make evidence-based decisions.

How much vitamin d3 per day for a woman?

The optimal dosage depends on your individual health needs, age, sex, and current nutrient levels. Recommended daily amounts are established by health authorities but may vary from therapeutic doses used in clinical research. It's important to check the Supplement Facts label for the exact amount per serving and compare it against the % Daily Value. Some supplements provide mega-doses well above the Daily Value, which may not be necessary and in some cases could be harmful — particularly for fat-soluble vitamins (A, D, E, K) that accumulate in the body. GoodSupp's efficacy analysis evaluates whether a product's dosages align with clinically studied amounts. Always consult your healthcare provider for personalized dosage recommendations.

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Disclaimer: GoodSupp provides independent supplement quality analysis for informational purposes only. Scores are generated algorithmically based on ingredient profiles, brand certifications, and public records. This is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Product data is sourced from manufacturer labels and public databases. GoodSupp is not affiliated with any supplement brand.