21st Century Soy Isoflavones Extract, Standardized, 60 Vegetarian Capsules (50 mg per Capsules) supplement bottle
21st Century

Soy Isoflavones Extract, Standardized, 60 Vegetarian Capsules (50 mg per Capsules)

What We Researched
2 active ingredients analyzed · 6 inactive ingredients decoded · 2 brand certifications checked · 3 retailers compared · Last updated: Mar 2026
83
Product Score Good
76
Brand Score Fair

Product Analysis

Transparency Excellent

Supplement Facts

IngredientAmount% DV
Soy Isoflavones Extract Powder (standardized to minimum 40% isoflavones) (seed) 100 mg **
Bioavailability Fair

Absorption Rating

  • Soy Isoflavones Extract Powder (standardized to minimum 40% isoflavones) (seed) Fair
Other Ingredients Excellent

Fillers & Additives

  • Oat Fiber
  • Rice Bran
  • Cellulose
  • Silicon Dioxide
  • Magnesium Silicate
  • Magnesium Stearate
Efficacy N/A

Dosage Analysis

Dosage data not available for assessment.

Supplement Facts

Ingredient Amount % Daily Value
Total Carbohydrate <1 g <1%‡
Soy Isoflavones Extract Powder (standardized to minimum 40% isoflavones) (seed) 100 mg **

Other Ingredients

Inactive ingredients used in manufacturing. All rated for safety.

Oat Fiber Generally_safe

It is used as a filler or source of fiber.

Rice Bran Safe

Natural filler and source of fiber.

Cellulose Safe

Provides bulk and structure in tablets and capsules.

Silicon Dioxide Safe

Prevents clumping and ensures consistent dosing.

Magnesium Silicate Generally_safe

It is used to improve powder flow and prevent clumping.

Magnesium Stearate Safe

Prevents ingredients from sticking to manufacturing equipment during tableting.

Price Comparison

Price History

Tracked across major retailers. Updated periodically.

$10$9$8$7$6 Mar 12 $7.99
iHerb

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

Brand Trust Report
21st Century

Founded 1991 · Tempe, Arizona, United States · 231 products · 21stcenturyvitamins.com/

Certifications

2 certifications
Consumerlab Verified
Nsf Gmp Verified Source

Transparency

4 claims
Third Party Testing Claim — Claimed Source
Testing Lab Disclosure — Verified Source
In House Testing — Verified Source

Violation History

4 incidents
Prop 65 Lead2021-06-22Source
Recall Vitamin D3 5000 IU Tablets2021-05-19Source
Lawsuit False advertising of Glucosamine/Chondroitin supplements.2012Source
Prop 65 Lead2008-12-23Source
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Frequently Asked Questions
Is 21st Century Soy Isoflavones Extract, Standardized a good supplement?

21st Century Soy Isoflavones Extract, Standardized, 60 Vegetarian Capsules (50 mg per Capsules) received a product quality score of 83/100 in GoodSupp's independent analysis, indicating strong overall quality. The product contains 2 active ingredients with 30 servings per container. Of the 6 inactive ingredients, 4 are rated safe and 0 are flagged for review. The manufacturer, 21st Century, holds a brand trust score of 76/100 with 2 verified certifications including Consumerlab, Nsf Gmp.

What are the ingredients in 21st Century Soy Isoflavones Extract, Standardized?

21st Century Soy Isoflavones Extract, Standardized contains 2 active ingredients: Total Carbohydrate (<1 g), Soy Isoflavones Extract Powder (standardized to minimum 40% isoflavones) (seed) (100 mg). Each ingredient's dosage, form, and safety rating is analyzed independently in GoodSupp's full product breakdown.

Is 21st Century Soy Isoflavones Extract, Standardized safe to take?

21st Century Soy Isoflavones Extract, Standardized, 60 Vegetarian Capsules (50 mg per Capsules) 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 21st Century a trustworthy supplement brand?

21st Century receives a brand trust score of 76/100 based on GoodSupp's independent analysis of certifications, regulatory history, and transparency practices. Founded in 1991 and headquartered in Tempe, Arizona, United States, the company offers 231 products in their lineup. They hold 2 verified certifications including Consumerlab, Nsf Gmp. Third-party certifications are independently verified and indicate the brand meets specific quality, purity, and manufacturing standards. Note: 21st Century has 4 historical regulatory incidents on record, which are factored into the trust score.

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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.