This is part 3 of my Vitamin D controversy series. To see the other posts in the series check out:
In 2024, the Endocrine Society published updated Clinical Practice Guidelines on Vitamin D in The Journal of Clinical Endocrinology & Metabolism. These guidelines were written by a completely new panel of experts and were accompanied by an important commentary:
In this paper, the authors made a striking statement:
“The Endocrine Society no longer endorses its previously proposed definition of vitamin D ‘sufficiency’ (≥30 ng/mL) or ‘insufficiency’ (20–30 ng/mL).”
This is a pretty remarkable shift.
Not only were the guidelines updated—but the authors explicitly walked back their previous definitions after more than a decade of widespread use.
Recap: The 2011 Endocrine Society guidelines
The 2011 guidelines defined vitamin D status as:
- Deficiency: <20 ng/mL (50nmol/L)
- Insufficiency: 20–30 ng/mL (50-75nmol/L)
- Sufficiency: >30 ng/mL (>75nmol/L)
These thresholds were widely adopted in clinical practice and laboratory reference ranges.
However, by around 2019, accumulating evidence suggested these cut-offs needed re-evaluation.
What is the correct threshold for action?
The short answer? We don’t know.
The 2024 guideline authors clearly state that the previous thresholds for action were not evidence-based and should no longer be used to guide clinical care.
A major shift: Less testing
One of the most important changes in the 2024 guidelines is the recommendation against routine vitamin D testing in many groups:
- Adults <50 years
- Adults 50–74 years
- Adults ≥75 years
- Pregnancy
- Individuals with darker skin pigmentation
- People living with obesity
This is a significant departure from prior practice.
Why the change?
Because there is:
- No clearly defined threshold that reliably guides clinical decisions
- No consistent evidence that testing and treating to higher targets improves outcomes
How much vitamin D should people take?
Another major shift is in supplementation recommendations.
In 2011, the Endocrine Society often recommended higher intakes than the Dietary Reference Intakes (DRIs).
In 2024: Recommendations now largely align with the DRI
This reflects the lack of evidence supporting benefit beyond standard intake levels for most populations.
Who should take a supplement?
The 2024 guidelines also narrowed the groups for whom routine (empiric) supplementation is recommended.
Empiric supplementation recommended:
- Children and adolescents
- Adults ≥75 years
- Pregnancy
- Individuals with high-risk prediabetes
No routine supplementation beyond DRI:
- Adults <50 years
- Adults 50–74 years
So what’s a clinician to do?
Given the widespread use of the 2011 guidelines—and the significant shift in 2024—this leaves many clinicians in a tricky position.
A few practical considerations:
- Reconsider routine testing
Ask: Will this result actually change management? - Check your lab’s reference range
Many labs still reflect older (2011) thresholds - Be familiar with the 2024 Endocrine Society or 2011 IOM Guidelines and interpret your lab results with these evidence-based thresholds instead
- Interpret results with caution
Especially if they are based on outdated definitions of “insufficiency” - Focus on adequacy, not optimization
The best evidence still supports:- ~16 ng/mL (40nmol/L) meets needs for ~50% of the population
- ~20 ng/mL (50nmol/L) meets needs for ~97.5%
Key takeaways
- The Endocrine Society has formally stepped back from its 2011 definitions
- There is no clear evidence-based threshold for action
- Routine vitamin D testing is no longer recommended for most groups
- Supplementation guidance now largely aligns with the DRIs
Up next
Part 4: Science, Bias, and Conflicts of Interest in Vitamin D
