Vitamin D3 + K2 (5000 IU)

Sports Research Vitamin D3 + K2 is Amazon's best seller in the D3-and-K2 category, and its appeal is easy to see: one small, plant-based softgel combines 5,000 IU (125 mcg) of vitamin D3 from lichen with 100 mcg of vitamin K2 as MK-7 from chickpeas, in coconut MCT oil inside a tapioca-based capsule. It is Certified Vegan and Non-GMO Project Verified, free of soy, gelatin and carrageenan, and the turmeric-tinted shell is there to protect the vitamins from light.

The dose is the main caveat. At 5,000 IU, a single softgel exceeds the 4,000 IU tolerable upper intake level for adults, and the label itself warns against combining it with other high-dose vitamin D. That can make sense for someone correcting a documented deficiency under medical guidance, but most people maintaining normal levels need less; Sports Research also sells 2,500 IU and 10,000 IU versions.

The K2 is a reasonable addition rather than a proven one. According to NIH, MK-7 is well absorbed and has a longer half-life than vitamin K1, but it is unclear whether any form of vitamin K supplement reduces osteoporosis risk, and evidence on arterial calcification is largely observational. Vitamin K also interacts with warfarin.

Quality assurance rests on the brand's own third-party testing and cGMP manufacturing rather than a USP or NSF seal. At $23.95 for 60 softgels (about 40 cents a day), buyers and creators praise the small, easy-to-swallow size; the complaints that surface on TikTok concern half-empty bottles and look-alike listings.