Designs for Sport Vitamin D+K Pro

You're crushing your training, but if you're deficient in vitamin D, you're leaving performance on the table. Vitamin D deficiency is common, nearly 30% of U.S. adults are deficient and another 40% are insufficient, and physically active populations aren't exempt: one study of young, active adults found vitamin D status was low across the group. That gap can affect muscle performance, immune resilience, and bone health, exactly the systems your training depends on.

Designs for Sport Vitamin D+K Pro pairs vitamin D3 with both K1 and K2 to help your body actually put the calcium it absorbs to use, and it's NSF Certified for Sport.

Complete Calcium Management System
Your body can't just absorb calcium, it needs to know where to put it. D3 drives absorption, but without K vitamins, that calcium can end up in your arteries instead of your bones. K1 supports healthy blood flow while K2 helps direct calcium to bones and teeth, where it builds density and strength.

A Dose Backed by Real Research
In a randomized, placebo-controlled trial, 2,000 IU of daily D3 for 12 weeks improved VO2 max, aerobic and anaerobic performance, and reduced fatigue compared to placebo. This formula delivers that same 2,000 IU of D3 per softgel, alongside 1,000 mcg each of K1 and K2.

Third-Party Verified
This formula is NSF Certified for Sport, tested for banned substances and label accuracy, worth knowing if you're a drug-tested athlete.

The Science Made Simple
Vitamin D3 is what your skin makes from sunlight, but unless you're training shirtless in the tropics, you're probably not getting enough. Vitamin D and K work synergistically: increasing vitamin D increases your body's need for vitamin K. K2 activates proteins called osteocalcin and matrix Gla protein, think of them as construction workers that build bone density while keeping calcium out of your arteries.

How to Use It
Daily dose: Take 1 softgel with a meal containing healthy fats, the fat helps absorption. Timing: Morning works great, but consistency matters more than timing. Pro tip: Get your vitamin D levels tested with a healthcare provider to find your actual target range, rather than guessing.

Vitamin K can interact with blood-thinning medications, so check with your healthcare practitioner before starting if you're on Coumadin, warfarin, or another anticoagulant.

Stop settling for compromised performance because you're training indoors or living north of the 35th parallel. This is your foundation for stronger bones, better cardiovascular support, and a body that's actually equipped to use the vitamin D you're giving it.