Question 1

Why do supplement dosage limits differ by country?

Accepted Answer

Authorities may use different populations, evidence, and risk-assessment methods, or may not establish a formal UL. For example, the US has a formal adult vitamin C UL while EFSA and Australia's NHMRC have not established one.

Question 2

Which supplement standard should I follow?

Accepted Answer

Start with the cited source for your region. If the authority has not established a formal UL, do not substitute another market's number or interpret the absence as unlimited safe intake; ask a qualified healthcare professional when your personal context matters.

Question 3

What is the difference between RDA and UL?

Accepted Answer

RDA (Recommended Dietary Allowance) is an intake level designed to meet the nutrient needs of nearly all healthy people in a defined group. UL (Tolerable Upper Intake Level) is the highest average daily intake likely to pose no adverse-effect risk for nearly all people in a defined group. Neither is personalized medical advice.

Supplement Dosage Comparison by Region

Why Do Supplement Dosage Limits Differ by Country?

Notable Differences Across Countries

IodineUL: 1100–3000 mcg

Vitamin DUL: 2000–4000 IU

Vitamin D2UL: 2000–4000 IU

Vitamin D3UL: 2000–4000 IU

Vitamin B1UL: 50–100 mg

What Are RDA and UL?

Is Your Supplement Dosage Safe?