Vitamin D Supreme by Designs for Health | Deep Dive

D-Evail™ Supreme is an advanced Vitamin D supplement from Designs for Health that delivers 5,000 IU (250 mcg) of highly absorbable Vitamin D as cholecalciferol, alongside vitamins K1 and K2 (as MK-4), Trans-geranylgeraniol (GG), and DeltaGold tocotrienols. This formula is specifically designed to support bone health, immune function, and cardiovascular wellness.

What distinguishes this Vitamin D supreme by designs for health product is its proprietary Evail™ system technology. This system uses a unique combination of Quillaja extract and medium-chain triglycerides (MCT) to enhance the absorption and bioavailability of the fat-soluble vitamins and nutrients within each softgel. Because Vitamin D is fat-soluble, it is best absorbed when taken with a meal or snack that includes some fat — and the MCT-based delivery system provides that lipid environment directly.

The formula comes in a 60-softgel bottle and is non-GMO, gluten-free, dairy-free, and soy-free.

The synergistic relationship between vitamins D and K is central to the design of this supplement. Vitamin D helps regulate calcium levels in the body by promoting intestinal calcium absorption and renal reabsorption. Meanwhile, vitamins K1 and K2 activate key calcium-regulating proteins — including osteocalcin and matrix Gla protein (MGP) — that direct calcium to the bones and teeth where it is needed, while helping to prevent excess calcium from accumulating in the arteries.

Research suggests that taking both vitamins together may be more beneficial than taking either one alone, particularly for bone and cardiovascular health. Carboxylated osteocalcin contributes directly to bone quality and strength, while activated MGP is the body's principal inhibitor of vascular calcification. This combined action supports strong, healthy bones and arterial flexibility.

The addition of Trans-geranylgeraniol (GG) further supports this relationship. GG is an obligatory substrate for the endogenous synthesis of both CoQ10 and vitamin K2 (MK-4), making it a mechanistically relevant complement to the vitamins D and K already present in the formula.

This formula may be particularly relevant for individuals with limited sun exposure — whether due to geographic location, indoor lifestyle, or darker skin pigmentation. Research notes that clouds, smog, older age, and having dark-colored skin reduce the amount of Vitamin D the skin makes, with pooled prevalence of Vitamin D deficiency in dark-skinned populations estimated at 77%.

Adults concerned about bone density may also find this combination formula relevant. Adequate Vitamin D is universally recommended alongside calcium for osteoporosis prevention, and Vitamin K supplementation has been shown in meta-analyses to significantly reduce fracture risk. Postmenopausal women, non-ambulatory individuals, and those on chronic steroid therapy may benefit from maintaining adequate levels of these nutrients.

People interested in cardiovascular wellness may appreciate the inclusion of vitamins K1 and K2, which activate matrix Gla protein to help keep calcium in the bones and out of the arteries. The addition of geranylgeraniol as a CoQ10 precursor adds further cardiovascular relevance.

Those seeking broad immune support may also benefit, as Vitamin D supplementation has been shown in meta-analyses to reduce acute respiratory infection incidence, particularly in individuals with low baseline Vitamin D status.

Take 1 softgel daily with a meal or as directed by your health-care practitioner.

Because Vitamin D and the other nutrients in this formula are fat-soluble, taking the softgel alongside a meal that contains some dietary fat may further support absorption — though the built-in MCT and Quillaja-based Evail™ system is already designed to optimize bioavailability.