The Best Supplements for Marathon Training

This time last year I was getting ready to run the London Marathon.  Long runs and recovery were a big part of my week.  As a Nutritional Therapist, of course I took my nutrition and fuelling strategy pretty seriously.  Training for a marathon is demanding, requiring the right balance of nutrition, hydration, and recovery.

Alongside my food plan, I added supplements and I believe these had a crucial role in my performance in long runs and on race day.  Supplements can help to fill nutritional gaps, enhance stamina, speeding up recovery and also support immune function and mood (race day anxiety can keep you awake for weeks before!)

In this guide, I bring you my thoughts on the best supplements for marathon training to help you perform at your peak.  You certainly don't need all of these and if you would like personalised recommendations then just drop me an email joanne@amaranth-wellbeing.com and we can arrange a free call.

 I have also prepared a handout that gives more information on that crucial fuelling strategy with menu ideas for your runs.  Fill in the form below and I will send you a copy.

1. Essential Vitamins and Minerals for Runners

B Vitamins for Energy Metabolism

B vitamins, including B12, B6, and folate, are essential for energy production, red blood cell formation, and reducing fatigue. Deficiencies can lead to decreased endurance and sluggish performance. A high-quality multivitamin like Viridian Sports Multi ensures adequate intake.

Magnesium for Muscle Recovery and Relaxation

Magnesium supports muscle relaxation, reduces cramps, and helps with stress and sleep—essential for endurance athletes. Viridian High Potency Magnesium provides a blend of three types of magnesium for optimal absorption.

Iron for Oxygen Transport

Iron is vital for carrying oxygen in the blood, preventing fatigue, and improving aerobic capacity. Female runners and those with plant-based diets should ensure they get enough iron through food or supplementation.

Vitamin D for Bone and Muscle Health

Vitamin D plays a critical role in bone strength, immune function, and muscle health. Since many runners train outdoors in winter or early mornings, supplementing with vitamin D is a smart choice.  Viridian D3 or Better You supplements are a good choice. I'm happy to advise on dosage.

Electrolytes for Hydration

Electrolytes such as sodium, potassium, and magnesium are crucial for maintaining hydration levels and preventing muscle cramps during long runs. My recommended electrolyte supplements are include Hunter & Gather sachets to take on long runs and  Viridian Electrolyte Fix, if you are able to take pre-pared drinks with you. I really like the Viridian Electrolyte Fix, the minerals are all in ionic form for quick, maximum absorption. You can also add these to water on non run days.

2. Protein and Recovery Supplements

Vegan and Whey Protein for Muscle Repair

Protein is necessary for muscle recovery and repair after long runs. A post run smoothie with berries, bananas, milk or juice and a protein source is a great idea. Some protein are full of artificial ingredients which is not good for the gut so choose a for high-quality protein powders or a collagen. My choices are :

• Vivo Life Perform (Vegan protein with turmeric and BCAAs for muscle repair)

• Supernova Women 01 (Plant-based protein with adaptogens)

• Natures Plus Collagen Peptides (Supports joint and muscle recovery)

• Planet Paleo Bone Broth Sport (A natural source of collagen and glutamine for faster recovery)

Omega-3 for Inflammation and Joint Health

Omega-3 fatty acids from fish oil help reduce inflammation and support joint health, crucial for runners putting stress on their knees and ankles. Bare Biology Omega-3  is my number one here. It is the top of the range for quality and dosage. Omega 3 is essential if you are not getting oily fish in your diet.

3. Performance-Enhancing Supplements

Beetroot for Stamina and Blood Flow

Beetroot is rich in nitrates, which increase nitric oxide levels, improving blood flow, oxygen delivery, and endurance. Beet-It Beetroot Shots are a popular pre-race supplement, best taken 2-3 hours before a long run.  An alternative is Mushrooms For Life Beetroot and Cordyceps.  This is designed as a latte powder but I often added to my smoothie, a couple of hours before heading out.

Cordyceps for Oxygen Utilisation

Cordyceps mushrooms have been found to enhance aerobic capacity, increase VO2 max, and improve endurance. My go to is Mushrooms For Life Organic Cordyceps Perform.

Carbohydrate Gels and Energy Chews

For energy during long runs, you will need carbohydrate gels and chews to help to maintain blood sugar levels. I explain more about this in the handout but Runners should aim for 30-40g of carbs per hour during a marathon, adjusting based on individual tolerance.  I really like the Veloforte chews and gels. Always practice with these well in advance of race day.  Gels can impact digestion and you definitely don't want that on a long run.

4. Immune System and Stress Support

Long runs put a stress on the body and this can mean that your immune system is put on hold a little.  If you are someone who struggles with colds and upper respiratory infections, this would be a good time to add some extra support.  You need to be at your best on race day.  I'm a big fan of. Terranova Beta Glucan with Astragalus and Vitamin C helps support immunity and recovery.

Adaptogenic herbs may also be helpful to support the stress response and improve resilience. Supernova Women 01 includes ashwagandha, maca, and chaga, alongside vegan protein. This is part of my daily life, running or not.

5. Topical and Recovery Aids

Magnesium for Muscle Tightness

After a run, a bit of TLC and some topical magnesium is a great addition:

• Better You Magnesium Spray (For muscle tightness and recovery)

• Magnesium Bath Salts (For relaxation and muscle repair)

If you do get pains and just need something to get you through the final day, Be Active Balm, for me, reduced the pain sensation and made running on a mild injury almost bearable.   Do not ignore pain leading up to race day though - it is a warning sign that something needs to be checked.

Final Thoughts

Supplements can significantly support marathon training by improving endurance, enhancing recovery, and reducing the risk of injuries. However, they should complement—not replace—a balanced diet rich in whole foods, quality protein, complex carbohydrates, and healthy fats.  Always speak to your GP or healthcare provider about supplements and medications your are taking. This blog is not a replacement for medical advice.

Before adding any new supplement, test it during training runs to ensure compatibility and avoid unexpected reactions on race day. With the right nutrition strategy and well-chosen supplements, you can optimise your performance and cross the finish line feeling strong!  Good Luck!

References available on request