Vitamin B5 (Pantothenic Acid)

Direct Answer

Vitamin B5 is an essential water-soluble vitamin required for the synthesis of Coenzyme A (CoA) and acyl carrier protein (ACP), vital in fatty acid synthesis and beta-oxidation. Adequate Intake (AI) is 5.0 mg/day (no Upper Limit established).

Source: NIH ODS / EFSA · Last reviewed Aug 28, 2026

Specs

Nutrient Type	Water-Soluble Amide Vitamin
Adult Adequate Intake (AI)	5.0 mg / day (6.0mg pregnancy, 7.0mg lactation)
Tolerable Upper Limit (UL)	None Established (Extremely low toxicity)
Chemical Forms	D-Pantothenic Acid, Calcium Pantothenate (Stable synthetic), Pantethine (Active dimer)
Primary Biological Function	Coenzyme A (CoA) backbone (Acetyl-CoA, Succinyl-CoA), Acyl Carrier Protein in fatty acid synthase, Steroid hormone synthesis
Deficiency Condition	Extremely rare ('Pantothen' = everywhere in foods); 'Burning Feet' syndrome (paresthesia), fatigue
Top Whole Food Sources	Shiitake Mushrooms, Beef Liver, Chicken Liver, Sunflower Seeds, Egg Yolk, Hass Avocado, Whole Milk
Thermal Processing Losses	20–50% lost during meat canning, boiling, and flour milling refining

The 4'-Phosphopantetheine Prosthetic Arm

Coenzyme A and fatty acid synthase use Vitamin B5's 4'-phosphopantetheine thiol arm as a flexible molecular swing that transfers acyl groups between enzymatic active sites.