Biotin (Vitamin B7)

What It Is:
A B-vitamin supporting hair, skin, and nail health, as well as metabolism of fats and carbs.

What It’s Used For:

• Cosmetic support (hair and nail strength)

• Metabolic health and enzyme function

Typical Dose:

• 30–100 µg daily (often much higher in beauty blends)

Side Effects:

• Very safe; large doses can skew lab test results

Why It’s Rated 1/5:
Beneficial for those deficient or with brittle nails, but no athletic or performance impact.