Pure Vegan, Advanced Vegan vs USANA Essentials

Vitamin D3 is a form of vitamin D.
Sources:
• "Explains the relationship between different forms of Vitamin D and how they are processed in the body."
Office of Dietary Supplements - National Institutes of Health - USA
Dietary Supplement Fact Sheet: Vitamin D
• "Vitamin D sources, methods of activiation in the body and uses"
byJane Higdon, Ph.D and Victoria J. Drake, Ph.D, Linus Pauling Institute
LPI - Micro Nutrient Info Center - Vitamin D
• "On Vitamin D chemistry, sources, biological actions and clinical significance"
byRichard S. Bak, Ph.D., Warde Medical Laboratory
Vitamin D and Metabolites
• "Human trial comparing potencies of Vitamins D2 and D3"
byRobert P. Heaney Robert R. Recker James Grote Ronald L. Horst Laura A. G. Armas, The Journal of Clinical Endocrinology & Metabolism
JCEM - Vitamin D3 Is More Potent Than Vitamin D2 in Humans

Niacinamide is a form of vitamin B3. Niacin is also called vitamin B3.
Sources:
• "Niacin and nicotinamide. What is it? How effective is it? How does it work? Are there safety concerns? Are there interactions with other medications or herb and supplements?"
Medline Plus
Medline Plus: Niacin and niacinamide (Vitamin B3)
• "Small Molecule Pathway Database (SMPDB): Nicotinate and Nicotinamide Metabolism (homosapiens)"
Genome Alberta & Genome Canada
SMPDB: Nicotinate and Nicotinamide Metabolism
• "Recommendations for niacin dosage by life stage and gender"
National Health and Medical Research Council - Australia, Ministry of Health - New Zealand
Niacin - Nutrient Reference Values Australia and New Zealand
• "Dietary supplement ingredient database: unit conversion tables"
National Institute of Health
Unit conversions for vitamins

Pyridoxine hydrochloride contains pyridoxine. The body converts pyridoxine to pyridoxal. The body converts pyridoxal to vitamin B6.
Sources:
• "Foundational Medicine Review 2001 Vol 6: Shows the most active form of Vitamin B6, Biochemistry and Clinical Applications"
Thorne Research
Foundational Medicine Review: Vitamin B6 (Pyridoxine; Pyridoxal 5'Phosphate)
• "The three main forms of Vitamin B6. Its effect on nervous system function, red blood cell formation, niacin formation, hormone function, nucleic acid synthesis, the RDA, disease prevention and treatment, sources, supplements and safety."
byJane Higdon, Ph.D and Victoria J. Drake, Ph.D, Linus Pauling Institute
LPI - Micro Nutrient Info Center - Vitamin B6
• "Tool for calculating molecular weights"
bywebqc.org, webqc.org
Web QC - Molecular Weight Calculation Tool

Both folic acid and folate are forms of vitamin B9.
Sources:
• "Small Molecule Pathway Database (SMPDB): Folate metabolism"
Genome Alberta, Genome British Columbia & Genome Canada
SMPDB: Folate Metabolism
• "Folate fact sheet for health professionals"
Office of Dietary Supplements - National Institutes of Health - USA
Folate fact sheet for Health Professionals

Levocarnitine tartrate contains L-carnitine. Both L-carnitine and L-cysteine are forms of amino acid. The body converts N-acetyl-L-cysteine to L-cysteine.
Sources:
• "PubChem: Cysteine - Compound Summary CID 5862"
National Center for Biotechnology Information - USA
PubChem: Cysteine - Compound Summary
• "Introduction to the chemistry of amino acids"
byDepartment of Biochemistry and Molecular Biophysics, University of Arizona
The Chemistry of Amino Acids
• "Cysteine - uses, dietary sources, available forms, how to take it, precautions, possible interactions "
St Luke's Hospital
Cysteine
• "PubChem - Levocarnitine Compound Summary"
National Center for Biotechnology Information
Pubchem: Levocarnitine - Compound Summary
• "PubChem - Levocarnitine Tartrate Compound Summary"
National Center for Biotechnology Information
National Center for Biotechnology Information. PubChem Database. Levocarnitine tartrate, CID=70700026 (accessed on Jan. 6, 2020)

Choline bitartrate contains choline.
Sources:
• "Tool for calculating molecular weights"
bywebqc.org, webqc.org
Web QC - Molecular Weight Calculation Tool

Grape seed extract contains procyanidin B2 3,3'-di-O-gallate. Both procyanidin B2 3,3'-di-O-gallate and epigallocatechin 3-O-gallate are forms of flavanol. Green tea extract decaffeinated contains epigallocatechin 3-O-gallate.
Sources:
• "Phenol Explorer - free access tool showing the amount of polyphenols in foods and metabolites"
byVarious, French National Institute for Agriculture et al.
Phenol-Explorer (Database on polyphenol content in foods)
• "(2004) Phenolic Compounds in Fruits and Vegetables. Phenolics in Food and Nutraceuticals. p 147 "
byFereidoon Shahidi, Marian Naczk
• "Study on procyanidin B2 3,3″-di-O-gallate and prostrate cancer"
byAlpna Tyagi,1 Komal Raina et al., University of Colorado
Procyanidin B2 3,3″-di-O-gallate, a biologically active constituent of grape seed extract, induces apoptosis in human prostate cancer cells via targeting NF-κB, Stat3 and AP1 transcription factors
• "Integrative Medicine - Green Tea"
Memorial Sloane Kettering Cancer Centre
MSKCC - Green Tea