Vitamin D needs are more subtle than you think. As mbg Chief Scientific Officer Ashley Jordan Ferreira, PhD, RDN, explains, “The question of daily vitamin D needs is directly related to your vitamin D status, as measured by serum 25-hydroxyvitamin D, or for short, 25(OH )D.”

The National Academies recommend a cutoff of 20 ng/mL for adequacy, while the Endocrine Society recently reviewed the science and recommended a cutoff of 30 ng/mL. As Ferreira explains, “to be clear, these limits are the numbers to avoid. In other words, you want to exceed 30 ng/ml every day for most of your life to get the full health benefits of vitamin D.”* In fact, vitamin D supplementation of less than 20 or 30 ng/ml is associated with suboptimal bone density (not something to mess with).

To stay healthy, you’ll want to know your 25(OH)D levels, which means asking your healthcare provider simple blood test6₆. It’s a clinical measurement of whole-body vitamin D status — and essential information if you want to track your baseline status and see how optimizing your vitamin D intake makes a big difference.*

Brittany Henderson, MD, a board-certified endocrinologist who specializes in hormones (including vitamin D) in her clinical practice, shares that “achieving optimal serum 25(OH)D levels in the 50+ ng/mL range is imperative lingual for immune health, bone health and much more.”*

Here’s where it gets interesting: Research shows that 100 IU of vitamin D3 (which is the body’s best form) per day increases the level of 25(OH)D in an average (healthy) adult by 1 ng/ml7₇. So, if you want to reach 50 ng/ml, 1000 or 2000 IU of vitamin D per day will not get you there; in fact, they won’t even get you to close. Based on these scientific findings, you would need about 5,000 IU per day to reach your optimal range.*