Supplements for Endurance Athletes

Endurance athletes get flooded with ads for powders, pills, and miracle drinks. The truth is, most of that stuff doesn’t really work. But a handful of supplements actually do make a difference, either by helping you perform better on the day or by speeding up recovery so you can train harder.

Let’s talk about the ones that are worth your attention. and common ones where where the evidence is shaky.

1. Performance-Oriented Supplements

Caffeine

If I had to pick just one supplement that actually works, it’s caffeine. It makes hard effort feels easier, sharpens your focus, and lets you push harder in both long sessions and short intense bouts.

Most people do best with around 3–6 milligrams per kilo of body weight, taken about an hour before exercise. If you’re racing for hours, a small top-up during the event can help you keep that edge. This isn’t a gimmick ; the science here is so strong that even the International Olympic Committee backs it.

If you’re curious to dig into the details, I have written a detailed article on Caffeine here: Sports Caffeine

How to Take It

• The simple way is coffee. One mug has about 80-100 mg, , so you can do the math based on your bodyweight.

• Energy gels and chews with caffeine are another solid option, especially during long races when you need both carbs and a mental lift.

  • (I personally love Maurten Gels. It has both caffeine and non-caffeine gels. I alternate between them in race)

• If you want a more precise approach, caffeine pills work really well. A standard pill is usually 100–200 mg, which makes it simple to hit your target dose without guesswork. ESN and ON makes great quality caffeine pills.

Just remember that caffeine can take 45–60 minutes to fully kick in, so time it accordingly. And like with anything, practice it in training first so you know how your body responds.

Nitric Oxide (Beetroot Juice, Nitrates)

Nitric oxide helps your blood flow better and makes your muscles use oxygen more efficiently. In simple terms, you can hold the same pace with less effort, or push harder without burning out as quickly. Foods like beetroot juice, spinach, and arugula are loaded with nitrates, which your body converts into nitric oxide. That’s why beet shots are so popular with endurance athletes.

How to Take It

• A common dose is 400–600 ml of beetroot juice or a concentrated shot taken 2–3 hours before exercise. Not everyone feels the same benefit, so test it during training first. And don’t worry if your pee turns red, that’s just the beets doing their thing.
  • (In India, Unived has beetroot powder for athletes)

Electrolytes

Electrolytes don’t make you faster on their own, but they stop you from slowing down. That alone is a huge performance win.

When you sweat, you lose sodium along with potassium and magnesium. Replacing only water throws off the balance and can lead to cramping, fatigue, or even dangerous low blood sodium. Electrolytes keep your muscles firing and help you hold pace, especially in long or hot sessions.

I explain this more here: Electrolytes and Running

How to Take It

• The easiest way is with drink mixes or tablets that go into your water bottle. Most athletes need somewhere between 300 and 800 mg of sodium per hour, depending on how much they sweat and how salty their sweat is.
• Some sports drinks already have electrolytes, but check the label to make sure it’s enough.
• You can also add a little extra salt to your meals before big races.

Fast&UP salt tablets are very common in India. While they are good, the sodium content is on lower side. I prefer Unived salt capsules.

Just like with caffeine, test your strategy in training so you’re not guessing on race day.

2. Recovery-Oriented Supplements

Vitamin D3 (with K2)

Vitamin D doesn’t give you a sudden boost during training, but it’s important for the long game. It keeps your bones strong, supports muscle function, and helps your immune system. A lot of athletes are low on vitamin D (especially for us in India), especially if they train indoors or live somewhere with little sunlight. Taking vitamin D3 helps fix that. Adding vitamin K2 is useful because it helps guide calcium into your bones.

Pairing D3 with K2 is smart because K2 directs calcium into your bones, not your arteries. Most of good D3 supplements come with K2 added.

How to Take It

• Most people do well with 1000–2000 IU a day, but the best way to know your dose is to get your blood levels checked. Since it’s a fat-soluble vitamin, take it with a meal that has some healthy fats like eggs, fish, or avocado.
• Carbamide Forte (available on Amazon) has good quality D3 and B12

Vitamin B12

Vitamin B12 is one of those nutrients you don’t really notice until you don’t have enough. It helps your body make red blood cells, which carry oxygen to your muscles, and it keeps your nervous system working properly.

If your levels are low, you’ll feel tired all the time, your recovery will be slower, and even your focus can take a hit. Vegetarians and vegans need to be extra careful since most B12 comes from animal foods like meat, eggs, and dairy. If your levels are normal, taking more won’t give you an extra boost. But if you’re deficient, fixing it can completely change how you feel in training.

How to Take It

• B12 supplements usually come in doses between 250 and 1000 mcg. They’re easy to find in tablet form, and you just let them dissolve in your mouth or swallow them like a regular pill.

The best move is to get your blood levels checked so you know if you actually need it.

3. What’s Not Worth It

• BCAAs: These get hyped a lot, but if you’re already eating enough protein, they don’t add much. Whole protein sources like eggs, dairy, meat, or plant protein powders do a far better job for recovery.

• High-dose antioxidants (Vitamin C, Vitamin E): More isn’t better here. Huge doses can actually mess with your body’s natural training response. You’re better off getting antioxidants from normal foods like fruits and veggies.

• Glutamine: It’s often sold as an immune booster, but for healthy endurance athletes, research doesn’t show much benefit. Save your money.

• Ketone esters: These are the shiny new thing in endurance sports. They’re pricey, the research is all over the place, and side effects are common. Not worth banking on right now.

Putting It Together

• For performance: Caffeine and nitrate-rich foods like beetroot have the strongest track record. Electrolytes keep you steady, especially in hot or long races.

  For recovery: Vitamin D3 (paired with K2 ), vitamin B12 if you’re low, and electrolytes for rehydration all play a clear role.

  What to skip: BCAAs, megadoses of antioxidants, glutamine, and ketone esters don’t live up to the hype.

Supplements can be useful, but they’re not magic. Think of them as the finishing touches that only matter once the big pieces : training, good food, sleep, and recovery are in place. For triathletes, the smart move isn’t chasing every new pill but sticking with the few that actually deliver.