What does vitamin D3 do?
Vitamin D3 (cholecalciferol) is one of the few vitamins our body can synthesize by itself. Its production is a complex process requiring exposure of skin to the sunlight. Other sources of vitamin D3 are seafood, meat and egg yolk. Vitamin D plays a vital role in the uptake and metabolism of calcium and phosphorus from our intestines . These processes are crucial for healthy bones and teeth and hence for restricting osteoporosis in elderly and for preventing rachitis in children. It is also recommended for pregnant and lactating women to increase their vitamin D3 levels due to the transmission of the vitamin from mother to infant. Furthermore, vitamin D3 deficiency is also related to weakness of the immune system, muscle strength  and premenstrual syndrome symptoms 
Why take vitamin D3 supplements?
There are multiple factors that can lead to a vitamin D deficiency. A contemporary indoor lifestyle often result in insufficient skin contact with sunlight, despite sunlight being the main source of vitamin D3 . Furthermore, the production of vitamin D3 is lower in people with a coloured skin [2,5]. Especially during darker months this can lead to a deficiency. People who do not get skin contact with the sun do not produce vitamin D3 by themselves and need to obtain it via another source. The alternative source of vitamin D3, natural food sources, contains little amounts of this vitamin. Hence the lack of exposure to sunlight is difficult to compensate with natural food sources . Supplementation of vitamin D3 is a simple way to prevent adverse effects of low concentrations of this nutrient. It is also recommended for pregnant and lactating women to increase their vitamin D3 levels due to the transmission of the vitamin from mother to infant [1,2,6,7].
The benefits of liposomal vitamin D3
Vitamin D3 is poorly miscible in water and hence difficult to absorb by the body. Liposomes enhance the uptake in the body, and are capable of protecting the vitamin against harmful bodily processes . For example, vitamin D3 is protected against oxidation and degradation when encapsulated in liposomes. These advantages combined lead to a higher bioavailability of vitamin D3, which means a higher chance of the vitamin reaching the target site. This makes liposomal vitamin D3 more effective than regular vitamin D3 .
 Holick, M. F. (2006). Resurrection of vitamin D deficiency and rickets. The Journal of clinical investigation, 116(8), 2062-2072.
 Holick, M. F. (2007). Vitamin D deficiency. New England Journal of Medicine, 357(3), 266-281.
 Fatemi, M., Allahdadian, M., & Bahadorani, M. (2019). Comparison of serum level of some trace elements and vitamin D between patients with premenstrual syndrome and normal controls: A cross-sectional study. International Journal of Reproductive Biomedicine, 17(9), 647.
 Wilson, L. R., Tripkovic, L., Hart, K. H., & Lanham-New, S. A. (2017). Vitamin D deficiency as a public health issue: using vitamin D 2 or vitamin D 3 in future fortification strategies. Proceedings of the Nutrition Society, 76(3), 392-399.
 Durazo-Arvizu, R. A., Camacho, P., Bovet, P., Forrester, T., Lambert, E. V., Plange-Rhule, J., … & Cooper, R. S. (2014). 25-Hydroxyvitamin D in African-origin populations at varying latitudes challenges the construct of a physiologic norm. The American journal of clinical nutrition, 100(3), 908-914.
 Hollis, B. W., & Wagner, C. L. (2004). Vitamin D requirements during lactation: high-dose maternal supplementation as therapy to prevent hypovitaminosis D for both the mother and the nursing infant. The American journal of clinical nutrition, 80(6), 1752S-1758S.
 Wagner, C. L., Hulsey, T. C., Fanning, D., Ebeling, M., & Hollis, B. W. (2006). High-dose vitamin D3 supplementation in a cohort of breastfeeding mothers and their infants: a 6-month follow-up pilot study. Breastfeeding Medicine, 1(2), 59-70.
 Akbarzadeh, A., Rezaei-Sadabady, R., Davaran, S., Joo, S. W., Zarghami, N., Hanifehpour, Y., … & Nejati-Koshki, K. (2013). Liposome: classification, preparation, and applications. Nanoscale research letters, 8(1), 102.
 Chaves, M. A., Oseliero Filho, P. L., Jange, C. G., Sinigaglia-Coimbra, R., Oliveira, C. L. P., & Pinho, S. C. (2018). Structural characterization of multilamellar liposomes coencapsulating curcumin and vitamin D3. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 549, 112-121.