Enduro D is a high-potency Vitamin D3 + K2 softgel supplement (30 caps) built for endurance athletes who train hard and need their foundations covered.
Quick Benefits
- Supports bone strength and skeletal integrity under heavy training loads.
- Boosts immune function during winter months and high-volume blocks.
- Promotes cardiovascular health by directing calcium to bones, not arteries.
- Helps improve insulin sensitivity for better energy and recovery.
What makes Enduro D different?
Most D3 supplements stop there. Enduro D pairs D3 with a dual K2 complex (MK4 + MK7) so calcium is properly directed to your bones and away from your arteries — critical for athletes logging serious training hours.
The D3 + K2 Synergy
Vitamin D3 (Cholecalciferol) — 2000 IU (250% DV)
- The most bioavailable form of vitamin D for immune and hormonal support.
- Essential during winter or low-sunlight training periods.
- Supports muscle function and reduces injury risk.
Vitamin K2 — 1680 mcg total (MK4 + MK7)
- MK4 (1500 mcg) — fast-acting form for immediate bone metabolism support.
- MK7 (180 mcg) — long-acting form for sustained cardiovascular protection.
- Works with D3 to activate proteins that bind calcium to bone tissue.
Who is it for?
Enduro D is ideal for cyclists, runners, and triathletes who train year-round and want to protect their bones, immunity, and cardiovascular system without adding complexity to their supplement stack.
Add Enduro D to Your Training Stack
How to Use
Take 1 softgel daily with a meal, or as directed by your healthcare professional. For best results, take consistently year-round and adjust based on seasonal sunlight exposure and training volume.
Nutritional Information
Serving size: 1 softgel | Servings per container: 30
- Calories: 5 | Cholesterol: <5 mg
- Vitamin D3 (Cholecalciferol): 50 mcg / 2000 IU — 250% DV
- Vitamin K2 as MK4: 1500 mcg
- Vitamin K2 as MK7: 180 mcg
Other ingredients: Capsule shell (gelatin, glycerin, water), olive oil.
Disclaimer: These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare professional before use.
Let customers speak for us
Extremely useful to use whilst cycling, removes the faff of opening gels whilst cycling and the solid bottle makes it easy to get in / out of jersey pockets.
Brilliant product - i use these in all my endurance events - some lasting up to 20 hours. These are great to ensure you get the required electrolytes without over hydrating.
Great service and the products are amazing, especially for endurance sports. I'm a big fan of the Endrolytes Electrolyte Caps. Their magnesium supplement and vitamin D are also very very good! I would highly recommend.
I’ve used Hammer products for around 6 years now & my favourite by a mile is the hammer Perpetuem, it’s fueled my last 100 mile ultra marathon not to mention multiple long distance triathlon's . It has 180calories per serving and it’s 34g of carbs & 5g of protein seems to work well . I’d strongly recommend for anyone who wants to take on ultra races as this fuel will support you when you need it most .
I started using Hammer Heed and Perpetuem 5 years ago and it's been such a game changer for my. Finding nutrition you can trust is so important for any athlete and I highly recommend Hammer Nutrition for any distance and any sport.
I couldnt race without hammer products. Heed is my favourite, such an amazing product. Paired with the gels it makes a great fueling recipe. Always fast shipping
Wonderful product for general Well being and Recovery. Great quick shipping.
Love all your products. I personally will concentrate on the perpetuum for my long swim(45km) as it feels like a meal every 4mins.
Thank you
great taste! great weight to calorie ratio! thanks
Great quality feel and easy to drink from whilst riding.
No plastic smells either.
Just need a few different colours?
Help me through a 70 miler. Would recommend 👌
Frequently Asked Questions
How long will my delivery take and how much does it cost?
Orders placed before 2:00 PM (UK time) are dispatched the same working day. Standard delivery to mainland Great Britain takes 2–5 days at a flat rate of £3.50, or free on orders over £10.
Large tubs are automatically upgraded to DPD next-day delivery. Shipping to Northern Ireland, the Channel Islands, and the Scottish Highlands costs £4.50, or free on orders over £80.
Can I change or cancel my order after placing it?
Because we process and dispatch orders quickly, we are usually unable to modify products, delivery methods, or addresses after submission.
To cancel an order, you must contact us on the same calendar day it was placed. If dispatch has already occurred, you can return the unused items within 14 days at your own shipping expense.
What is your returns policy if I change my mind?
You have 14 days from the day after delivery to cancel your order. Items must be unused, in their original packaging, and in resaleable condition. Important Step:
You must email us via the bottom of our Home Page first to obtain a Returns Authorisation Number and a free Royal Mail returns sticker; unauthorised returns cannot be processed.
Note that opened, sealed supplements cannot be returned for hygiene reasons.
What should I do if my order is damaged, faulty, or incorrect?
Check your parcel immediately upon arrival. If there is an issue, notify us within 48 hours of delivery via teh contact us at the bottom of our Home page.
Please include your order number, a description of the issue, and photos of the damaged items and packaging. We will provide a free replacement or full refund.
How long do refunds take to process?
Once your return is received, inspected, and approved, we process refunds back to your original payment method (card, PayPal, or bank transfer).
This typically takes place within 7 working days, and always within a maximum window of 30 days.
Are Hammer Nutrition products safe for drug-tested athletes?
Yes. Key products within our range—including Endurolytes (4ct/120ct), Endurolytes Extreme (3ct/120ct), Endurolytes Extreme Powder, and Endurolytes Fizz - are officially Informed Sport certified.
Additionally, our products are manufactured in strict ISO, GMP-compliant, and SQF Level 3 Certified facilities to ensure the highest standards of food safety and purity.
What do you use to flavour your sports nutrition products?
We use only premium ingredients with zero artificial flavours, artificial sweeteners, or chemical colorants.
Our natural flavours are extracted from real food sources (such as fruits, essential oils, and botanicals) in full compliance with FDA regulations.
They are entirely derived from non-allergenic materials and are formulated for a clean, subtle, non-sweet taste.
What should I do if my order has not arrived?
Estimated transit times are 2–5 days. If your parcel has not arrived within 5 days of placing your order, notify us immediately via our contact us at the bottom of our Home page.
We will launch an investigation with the carrier and provide updates or arrange a replacement where appropriate.
Do you accept backorders for out-of-stock items?
No, we do not accept backorders. If an item is currently unavailable, you can enter your email address in the "email me when back in stock" widget directly on the product page to receive an automated real-time notification the moment inventory is replenished.
Are your supplements suitable for specific dietary restrictions?
Our clean sports nutrition range is formulated to support optimal body function and is completely free from gluten, artificial preservatives, and artificial colorants.
If you have specific medical conditions or severe allergen concerns, we recommend checking the explicit ingredient panels or consulting a healthcare professional prior to consumption.