# Vitamin B5 (Pantothenic Acid)

**Summary**  
Vitamin B5 (Pantothenic Acid) is a water-soluble vitamin which serves a key role in the synthesis of CoA (coenzyme A), a cofactor in many metabolic reactions. It is also plays a role in fatty acid synthesis, as it is a cofactor for the enzyme fatty acid synthase (FAS). Vitamin B5 Deficiency is rare, and primarily presents with symptoms of gastroenteritis (diarrhea), with possible adrenal insufficiency, dermatitis, or alopecia.

**Key Points**  
- **Vitamin B5 (Pantothenic Acid)**  
  - Essential cofactor for:  
    - **coenzyme A (CoA)**  
      - cofactor for acyl transfers  
      - key role in first step of TCA cycle ( **oxaloacetate to citrate**)
    - **fatty acid synthase**  
- Deficiency (low yield)  
  - rare, seen in the severely malnourished  
    - enteritis/GI distress  
    - dermatis, alopecia, and adrenal insufficiency also seen

Find Vitamin B5 and other [Vitamins](/content/browse#playlist-2700/index.html) among Pixorize's visual mnemonics for the USMLE Step 1 and NBME shelf exams.