Thorne High Potency Vitamin C

You train hard. Your immune system pays the price. Most athletes don't realize that intense endurance training — long rides, big run weeks, back-to-back workouts — temporarily suppresses your immune system and floods your body with oxidative stress. That "open window" after a hard effort is when you're most vulnerable. Standard vitamin C supplements can help, but high doses of regular ascorbic acid wreck your stomach before they can do any good.

Thorne High Potency Vitamin C is the buffered vitamin C powder trusted by elite athletes and over 100 professional sports teams — delivering 2,350mg of vitamin C per serving without the digestive discomfort that stops most people from getting the dose they actually need.

Stomach-Friendly at High Doses
Thorne bonds the ascorbic acid with calcium, magnesium, and potassium — turning it into a buffered form that neutralizes the acidity. You get a therapeutic dose of vitamin C without the cramping or GI distress that comes with standard powders.

More Than Just Vitamin C
Each scoop delivers meaningful amounts of three key minerals — the same minerals that keep your muscles contracting, your heart rhythm steady, and your bones strong under training load. You're not just topping up your C levels; you're reinforcing your foundation.

Clean, Flexible, and Third-Party Certified
No fillers. No capsules. No artificial anything. Just an unflavored powder that dissolves fast in water or your favorite drink. Thorne is third-party tested and certified — what's on the label is what's in the bag. No surprises.

Vitamin C does something most athletes underestimate: it's the essential cofactor your body uses to build collagen — the structural tissue holding your tendons, ligaments, and connective tissue together. Every long run and hard ride stresses those tissues. Vitamin C is what lets your body repair them. It also neutralizes the free radicals your muscles generate during intense effort, reducing the cellular damage that accumulates over a training block. Your body can't make vitamin C on its own. At high training loads, dietary intake often isn't enough.

Take it daily: Mix one scoop into at least 8 oz of water or your post-workout drink once per day.

Time it strategically: Take it after hard sessions when oxidative stress is highest and your immune system needs the most support.

Pro tip: Pair it with your recovery meal — vitamin C enhances iron absorption from food, which matters for endurance athletes.

Thorne is the #1 recommended supplement brand by healthcare practitioners and is the trusted partner of U.S. National Teams. Athletes who use high-dose buffered vitamin C consistently report fewer sick days and shorter recovery windows — which means more consistent training weeks.

This isn't just another vitamin C supplement. This is your daily defense against the immune dips and tissue breakdown that derail training blocks.