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Life Extension D, L-Phenylalanine 500 mg supplement bottle
Life Extension

D, L-Phenylalanine 500 mg Review

What We Researched
1 active ingredient analyzed · 3 inactive ingredients decoded · 4 brand certifications checked · Page generated: Sep 2026
100
Product Score Excellent
87
Brand Score Good

Two independent scores — the product and the brand behind it, never blended into one number. See our methodology.

Product Analysis

Transparency Excellent

Supplement Facts

IngredientAmount% DV
D, L-Phenylalanine 500 mg **
Bioavailability Excellent

Absorption Rating

  • D, L-Phenylalanine Good
Other Ingredients Excellent

Fillers & Additives

  • Vegetable Cellulose (Capsule)
  • Vegetable Stearate
  • Microcrystalline Cellulose
Efficacy Excellent

Dosage Analysis

  • D, L-Phenylalanine 500 mg Effective

Supplement Facts

Ingredient Amount % Daily Value
D, L-Phenylalanine 500 mg **

Other Ingredients

Inactive ingredients used in manufacturing. All rated for safety.

Vegetable Cellulose (Capsule) Safe

It is used as a material for making vegetarian capsules.

Vegetable Stearate Safe

Prevents ingredients from sticking to equipment.

Microcrystalline Cellulose Safe

Adds bulk to small-dose supplements to make tablets/capsules a manageable size.

Brand Trust Report
Life Extension

Founded 1980 · Fort Lauderdale, Florida, USA · 700 products · lifeextension.com

Certifications

4 certifications
Consumerlab Source available Primary evidence
Fda Gmp Inspections Source available Primary evidence
Nsf Gmp Source available Primary evidence
NSF Certified Supporting evidence unavailable

Transparency

4 claims
Third Party Testing Claim — Verified Evidence available Evidence
Coa Availability — Verified Evidence available Evidence
Testing Lab Disclosure — Claimed Brand claim; evidence unavailable

Violation History

3 incidents
Prop 65 Lead2018-04-13 Source available Primary source
Fda Warning Making drug claims for dietary supplements, suggesting they can treat, mitigate, or prevent diseases such as breast cancer and Alzheimer's.2017-02-01 Source available Primary source
Fda Warning Letter FDA Warning Letter Source available Primary source
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Frequently Asked Questions
Is Life Extension D, L-Phenylalanine 500 mg a good supplement?

Life Extension D, L-Phenylalanine 500 mg received a product quality score of 100/100 in GoodSupp's independent analysis, placing it in the top tier of supplements we've analyzed. The product contains 1 active ingredients All 3 inactive ingredients (fillers, binders, capsule materials) are rated safe — a clean formulation with no flagged additives. The manufacturer, Life Extension, holds a brand trust score of 87/100.

What are the ingredients in Life Extension D, L-Phenylalanine 500 mg?

Life Extension D, L-Phenylalanine 500 mg contains 1 active ingredients: D, L-Phenylalanine (500 mg). Each ingredient's dosage, form, and safety rating is analyzed independently in GoodSupp's full product breakdown.

Is Life Extension D, L-Phenylalanine 500 mg safe to take?

GoodSupp reviewed the inactive-ingredient data available for Life Extension D, L-Phenylalanine 500 mg. All 3 inactive ingredients — including capsule materials, fillers, and binders — are currently classified as safe in GoodSupp's ingredient reference data. This label analysis cannot determine whether the product is safe for a particular person, and source labels may change. Always consult your healthcare provider before starting any new supplement, especially if you take medications or have underlying health conditions.

Is Life Extension a trustworthy supplement brand?

Life Extension receives a brand trust score of 87/100 based on GoodSupp's independent analysis of certifications, regulatory history, and transparency practices. Founded in 1980 and headquartered in Fort Lauderdale, Florida, USA, the company offers 700 products in their lineup. Note: Life Extension has 3 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 — read our methodology. 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.