The Vitamin D Mistake

The clocks just went back, and the sun’s about to ghost us like an online date with a better option—which means we’re all about to spend more hours indoors and in darkness.

It’s exactly at this time of year that one molecule quietly offers a French exit: Vitamin D.

The consensus across countless health guidelines is clear: supplement during the colder months. The NHS recommends 400 IU per day from October to April.

Garbage RDA

But is that enough? Not even close.

The official line is that a Recommended Daily Allowance (RDA) of 400 IU per day is sufficient. However, independent statisticians have exposed a fundamental error in that calculation.

In 2014, two researchers published a letter titled: “A statistical error in the estimation of the recommended dietary allowance for Vitamin D.”

Their recalculation of the same data yielded an RDA of 8,895 IU/day.

A year later, another group reviewed the math and proposed a revised figure of 7,000 IU/day… yet no regulatory updates followed. Why?

Because what gets printed on labels isn’t what our body needs to perform. It’s the “safe minimum.” A number chosen to prevent disease, not promote resilience.

Of course, not everyone needs the same dose. Sun exposure, skin tone and body composition all shape how we process D. But for most of us, 400 IU barely scratches the surface.

A common pushback is: “But isn’t too much Vitamin D dangerous?”

Toxicity can occur, yes, but that’s typically at sustained doses over 10,000 IU/day. The tolerable upper limit set by conservative health authorities is already 4,000 IU/day.

In other words: if you’re worried about toxicity from taking 1,000–2,000 IU/day, you’re more likely to be underdosing than overdosing.

Everything That Glitters

Our skin is a solar factory. In summer/spring, midday sun for 10–15 minutes with 22% of skin uncovered, we generate about 1000 IU. But in autumn and winter in the UK, ultraviolet intensity drops too low for effective D3 synthesis. As a result, our balance depletes, and our system starts drawing on stored D. If we have any left.

Vitamin D is fat-soluble, and stored in adipose tissue, liver, and muscle. It has a half-life of about 15 days, so we can hold onto it for a while. Our body activates it through a process called hydroxylation converting it to a hormone like molecule that regulates immunity, inflammation, neuromuscular control and sleep regulation. 

When we’re too low, you’ll experience slower recovery, poor sleep and circadian disruption, low mood, weak immunity and weaker bones/muscles.

As daylight dwindles and stress ramps up, our body needs to regulate and rebound faster. Vitamin D is one of the unsung regulators of that adaptive capacity.

In short, Vitamin D is a key regulator of system resilience. Something we're big on. That’s why you’ll find 1,000 IU of it in each of our shots, alongside 28 other remarkable ingredients designed to fuel the body for the pace of modern life. 

Get your starter pack today before the night stretches out its arms a little further. To lighten the load, use code DISCTWENTY for 20% off.