While there is no official Recommended Dietary Allowance (RDA) for biotin due to its rarity of deficiency, an Adequate Intake (AI) of 30 micrograms (mcg) per day is established for adults. However, many supplements contain significantly higher doses, often ranging from 1,000 mcg to 10,000 mcg, particularly for those looking to support hair, skin, and nail health. Always consult product labels and a healthcare professional for personalized guidance.