Mushroom-powered Vitamin D: Why We Chose Mushrooms for Our Plant-Based Vitamin D

What if your daily vitamin D started with something as simple as mushrooms and light?

Our relationship with vitamin D begins with the sun. When sunlight reaches our skin, our bodies can make vitamin D. Mushrooms have their own relationship with light, when they are exposed to light, they naturally produce vitamin D too. 

This simple, whole-food source of vitamin D has been something we’ve really wanted to offer in our product range for years because not only do we love our mushrooms, we also love simplicity. 

What is vitamin D and why does it matter?

Vitamin D is one of the nutrients our bodies need every day. It contributes to the normal function of the immune system, the maintenance of normal bones and teeth, and normal muscle function.

Our bodies can make vitamin D when our skin is exposed to sunlight. But in the UK, this becomes more difficult as the seasons change. From around October to early March, sunlight is not strong enough for most people to make sufficient vitamin D, which is why the NHS advises everyone to consider taking a daily vitamin D supplement during autumn and winter.

For us, the question wasn’t just why vitamin D matters, but where it should come from.

How do mushrooms make vitamin D?

Mushrooms naturally contain a compound called ergosterol. When certain mushrooms are exposed to light, this compound is converted into vitamin D2.

It’s a fascinating natural process. In much the same way that our skin responds to sunlight by producing vitamin D, mushrooms respond to light by producing vitamin D2. This gave us a starting point that felt both simple and distinctive: using the natural biology of mushrooms to create a whole-food source of vitamin D2.

Vitamin D2 vs D3: what’s the difference?

Vitamin D comes in two main forms: D2 (ergocalciferol) and D3 (cholecalciferol). Both help maintain healthy vitamin D levels, supporting normal bones, muscles, and immune function, but they differ in their sources.

Vitamin D3 is the form you’ll often see in supplements. It can be derived from animal sources such as lanolin (from sheep’s wool), although vegan D3 made from sources such as lichen is also available. D3 is also produced naturally in your skin when exposed to sunlight.

Vitamin D2, on the other hand, is found in fungi, including mushrooms and certain yeasts. Exposing mushrooms to light increases their naturally occurring vitamin D2 content, creating a source that fits naturally with a plant-based approach. Fun fact: if you put a bowl of mushrooms in the sunlight for the afternoon before you cook with them, they will have absorbed more vitamin D! 

Both D2 and D3 are fat-soluble vitamins, meaning they dissolve in fat rather than water. 

Why we chose Earthlight® mushroom-powered vitamin D

At The Herbtender, we wanted a vitamin D that was plant-based, minimally processed, and thoughtfully sourced, with a clear, recognisable starting point and no unnecessary extras.

That’s why we chose Earthlight® mushroom-powered Vitamin D2. Made from whole mushrooms exposed to light, then dried and milled into a fine powder, the ingredient is exactly that: powdered mushroom. No other ingredients are needed to keep the compound stable.

We chose Earthlight® because it brings together the qualities we were looking for: whole-mushroom nutrition, a low-energy production process, sustainability, and independently verified potency.

Mushrooms are widely recognised as a sustainable food source, requiring little land and water compared with many conventional crops and animal-based foods. Earthlight® builds on this with a production process designed to use energy efficiently.

Unlike isolated vitamin D ingredients, Earthlight® remains a whole-food mushroom powder. The vitamin D is delivered alongside the naturally occurring constituents of the mushroom itself, rather than being separated into an isolated nutrient extract.

Despite this minimal processing, Earthlight® is a concentrated source of vitamin D, providing 1,000 μg (40,000 IU) per gram. Its potency is independently verified, giving us the consistency needed from a modern supplement ingredient.

For us, this is what thoughtful formulation looks like: full ingredient transparency, considered sourcing and ingredients that earn their place.

Why our vitamin D contains Lion’s Mane

What fills the rest of a supplement capsule?

Vitamin D is needed in relatively small amounts, which can leave space inside a capsule. Traditionally, this space might be filled with a conventional bulking agent. We wanted to take a different approach.

If something needed to fill the capsule, we wanted it to be something we’d actively choose to include. So, we chose organic Lion’s Mane fruiting body powder. More mushroom, rather than a conventional bulking agent.

It’s a small detail, but it reflects how we approach formulation. Thoughtful formulation isn’t always about adding more; sometimes it’s about making sure everything earns its place.

When should you take a vitamin D supplement in the UK?

During spring and summer, most people should be able to make the vitamin D they need from sunlight on their skin. But from around October to early March, sunlight in the UK isn’t strong enough for most people to make sufficient vitamin D.

The NHS advises everyone to consider taking a daily vitamin D supplement during autumn and winter. Some people are also advised to consider taking vitamin D throughout the year, including those who spend very little time outdoors or whose skin has little or no exposure to sunlight.

Always follow the directions for your supplement and seek professional advice if you’re unsure what’s appropriate for you.

Is mushroom vitamin D suitable for vegans?

Vitamin D isn’t always plant-based. Some vitamin D3 supplements use vitamin D derived from lanolin, a substance obtained from sheep, although vegan D3 options are also available.

Mushroom-derived vitamin D provides another option. Our vitamin D starts with mushrooms rather than an animal source, which fits naturally with our plant-based approach.

For us, that means asking a simple question when we’re formulating: can plants and nature give us what we’re looking for before we look elsewhere? In the case of our vitamin D, the answer was mushrooms.

Vitamin D the Herbtender way

Wellness can often feel complicated. There’s always something new to add, track or fit into your routine. But underneath all that noise, our bodies still need the basics.

That’s the thinking behind adding vitamin D to our range as a daily foundation: built around what the body fundamentally needs and formulated with care and purpose.

Our Vitamin D + K2 brings together:

• Mushroom-powered vitamin D2
• Vitamin K2
• Organic Lion’s Mane fruiting body powder
  
• Plant-based ingredients
• Nothing unnecessary
  

We believe innovation doesn’t need to move further away from nature. Sometimes it means finding a smarter way to be closer to nature, by design.