Vitamin D/K2 Liquid
Thorne is the gold standard for purity and professional-grade sourcing, featuring a highly bioavailable liquid D3/K2 combination. The NSF Certified for Sport designation ensures it is free from over 200 banned substances, making it the top choice for athletes and high-performance individuals.
Ingredients & Purity
Uses Vitamin D3 (Cholecalciferol) and Vitamin K2 (as MK-4), which works synergistically with D3 to support calcium metabolism. The carrier is medium-chain triglyceride (MCT) oil with mixed tocopherols as antioxidants.
Scientific Evidence
Thorne is a partner of the Mayo Clinic and is NSF Certified for Sport. Clinical studies consistently show liquid D3/K2 formulations have superior absorption in individuals with fat malabsorption issues.
Brand Transparency
Thorne conducts in-house testing on every batch and provides detailed manufacturing information. They are one of the few brands that own their entire manufacturing process in an NSF-certified facility.
Value Assessment
While the upfront cost is higher ($30), the bottle contains 600 drops (approx. 500 IU per drop), making the cost per effective dose quite reasonable for a premium product.
Why Not Alternatives?
Unlike many liquid competitors that use soybean or vegetable oils, Thorne uses a clean MCT oil base. It avoids the 'proprietary blends' and synthetic fillers found in brands like Garden of Life or New Chapter.