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If you’ve been told to load up on vitamin D to help with MS, you’re not alone.

For years, that’s been the message within the MS community: take vitamin D. Lots of it to lower your risk of symptoms and relapse. It seemed like the simplest and cheapest addition to our wellness routine. And bonus? Both conventional and functional medicine agreed on it.

But now, new research is calling all of that into question.

Two recent studies: one from Johns Hopkins University and another from Australia and New Zealand—concluded that high doses of vitamin D didn’t significantly reduce MS activity or delay progression. It’s confusing, disappointing, and for many of us, a little scary.

But before you toss those vitamin D bottles in the trash, let’s take a closer look.

What We Thought We Knew About Vitamin D and MS

Low vitamin D levels have long been associated with:

• Higher rates of relapse
• Increased disability
• Brain atrophy
• Other chronic conditions like autoimmune diseases, cardiovascular disease, and even cancer

So, naturally, many of us leaned on it as a foundational piece of our health strategy. It felt like a no-brainer.

Personally, I make it a point to have my levels tested at least twice a year. When I was first diagnosed, my vitamin D was a shocking 11. With my doctor’s guidance, I supplemented heavily and eventually reached a stable 50, right in the optimal range. That shift, combined with other lifestyle changes, brought more stability and energy into my life.

It’s worth noting that vitamin D is a fat-soluble vitamin, which means your body stores it. It doesn’t just flush out like vitamin C or the B vitamins. So testing is key. More isn’t always better.

The New Research: What It Found

Study 1: Johns Hopkins University
This study looked at people with relapsing-remitting MS (the most common type) and compared high doses of vitamin D to lower doses. After 96 weeks, they found no significant difference in relapses or brain lesions between the two groups.

Study 2: Australia–New Zealand
This one focused on people with clinically isolated syndrome (CIS), which is often a precursor to MS. The goal was to see if vitamin D could delay a full MS diagnosis. After 48 weeks, vitamin D didn’t appear to change the outcome.

On the surface, these results are disappointing. But here’s the thing: the participants didn’t start off with severely low vitamin D levels. So we’re still left wondering—what about those of us who were deficient?

When I think back to how low my levels were at diagnosis, I can’t help but question whether these findings apply to someone in my shoes.

Is It Just About the Supplement?

There’s another angle we need to consider.

Rates of MS are significantly lower near the equator, where sun exposure is higher. That’s what led researchers to connect sunshine to vitamin D in the first place. But what if it’s not just the vitamin D we’re getting from the sun? What if sunshine offers more than what can be captured in a supplement?

This is the same concept we see with food. You can isolate a nutrient from broccoli and put it in a pill but it won’t give you all the benefits that come from eating real, whole broccoli.

Sunlight may work the same way.

I know for many of us with heat intolerance, being out in the sun is tricky. Personally, I aim for short, manageable bursts of sunshine. Being near water like a pool or the ocean helps me stay cool. I also try to take advantage of cooler days when I can enjoy the sun without overwhelming my system.

So… Should You Still Take Vitamin D?

Here’s my personal take:

• I’ll still be checking my vitamin D levels twice a year.
• I’ll still supplement as needed to stay within an optimal range.
• And I’ll still be intentional about spending time in the sun.

Because even if vitamin D supplements don’t prevent relapses, they do support immune function, mood, and energy. And I’ve felt the difference firsthand.

Plus, with the winter months ahead, low vitamin D can contribute to seasonal depression, something many of us already struggle with. So staying on top of your levels can be a key part of managing mood and mental health, too.

Bottom Line

These new studies don’t necessarily mean vitamin D is useless. But they do challenge the idea that more is always better.

For me and maybe for you too, vitamin D will still have a place in my MS toolbox. I’m just using it with more intention and continuing to focus on the full picture of my health: sunshine, food, movement, rest, and connection.

It’s all about balance.

Want more encouragement like this? Tune into this week’s special episode of My MS Podcast:
🎧 Vitamin D: Does It Help MS?
Listen now to My MS Podcast.