Vitamin D3


Vitamin D is a fat-soluble vitamin that plays a role in bone health, several cellular processes, and the maintenance of calcium and phosphorus levels in the body.

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Adequate vitamin D and calcium help protect against osteoporosis in elderly men and postmenopausal women.

Vitamin D deficiency is associated with several risk factors for cardiovascular disease.

Some studies have shown that vitamin D supplementation can improve sexual functioning and increase testosterone levels in men who are vitamin D deficient.

It is recommended that men have at least 15–50 mcg (600–2,000 IU) per day of vitamin D, which can come from food, exposure to sunlight, supplements, or a combination of these. Having too much or too little can be dangerous for your health.

Vitamin D supplements can interact with certain medications. Talk to your healthcare provider before taking vitamin D if you are already taking cholestyramine, corticosteroids, orlistat, or seizure medications.

Talk to your healthcare provider if you are concerned about any side effects you experience.

What is vitamin D?

Vitamin D is a fat-soluble vitamin that is involved in several of the body’s processes. The other fat-soluble vitamins are vitamin A, vitamin E, and vitamin K, and all four of these vitamins can be stored in the fatty tissues of the body. The primary role of vitamin D in the body is to help maintain appropriate levels of calcium and phosphorus. It does this by impacting both how calcium is absorbed from food as well as how the body builds and reabsorbs bone, a process called bone remodeling. Vitamin D’s effects on the bone are due to its activity on cells called osteoblasts (which build bone) and osteoclasts (which reabsorb bone). Vitamin D also plays a role in certain cellular functions, like cell growth, differentiation (the process that allows a cell to do its specific job), and cell death.

Where does vitamin D come from?

Vitamin D can be obtained through food, however very few sources contain it. Animal sources include fatty fish such as salmon, beef liver, and egg yolks. Plant sources include certain kinds of mushrooms. Most food-based vitamin D in the United States comes from foods that have been fortified with vitamin D, which means it is artificially added to the food in a public health effort to help make sure everybody is getting enough each day. Foods that are often fortified with vitamin D include milk, cereal, margarine, orange juice, and yogurt (2).

Vitamin D can also be made by the body when the skin is exposed to direct sunlight. Ultraviolet B (UVB) rays from the sun cause a reaction in the skin, making vitamin D3 out of a type of cholesterol called 7-dehydrocholesterol. It is estimated that only 5–30 minutes of direct sun exposure twice weekly creates adequate levels of vitamin D in the body for most people. Factors affecting how well an individual makes vitamin D from the sun include the time of day/year, the weather, how dark the person’s skin is (how much melanin they have), and whether the person is wearing sunscreen (which blocks UVB). The latitude that somebody lives at is not a good predictor of vitamin D levels. Currently, there are no recommendations regarding how much vitamin D should be obtained from the sun since exposure to UVB can also cause skin damage and cancer. Using sunscreen and avoiding any behaviors that might lead to sunburn are still recommended.

Before it is biologically active, vitamin D obtained from food, supplements, and sunlight needs to change form. First, the liver converts vitamin D to 25(OH)D (calcifediol). Next, the kidneys convert this compound into 1,25(OH)2D (calcitriol). Calcitriol is the active form of vitamin D in the body. Measuring 25(OH)D can be useful to assess body stores of vitamin D, however optimal levels of 25(OH)D and how exactly these levels translate to health have not been well established.

What are the health benefits of vitamin D?

There are a few purported benefits of vitamin D that are either unconfirmed or that do not have enough supporting evidence. These include using vitamin D to prevent and treat diabetes, hypertension, and multiple sclerosis. There has also been conflicting evidence as to whether vitamin D supplementation can improve life expectancy. One analysis initially found that vitamin D supplementation was associated with an improved life expectancy, but a second review of the data (and another subsequent study) did not find this association (2). More studies need to be conducted to better determine whether vitamin D supplementation actually confers any sort of longevity benefit.

Many studies have looked into the efficacy of vitamin D supplementation for the treatment of depression. One review found that, amongst the studies that did not have flaws, vitamin D supplementation is associated with improvement of depression (6).

Vitamin D also has the following health benefits, which is why it was chosen to be an ingredient in the Roman Dailies:

    Heart Health

    Vitamin D supplementation may be beneficial for those who are vitamin D deficient. One study found that vitamin D deficiency is associated with several cardiovascular disease risk factors, such as hypertension, coronary artery disease, cardiomyopathy (disease of the heart muscle), and diabetes. The study also found that vitamin D supplementation was associated with better survival (10). However, other studies that have not found that vitamin D supplementation in healthy individuals reduces cardiovascular events (2).

    Testosterone Support

    Studies looking specifically at vitamin D’s effects on men are limited. They include the following:

    • Erectile dysfunction: One small study found that high levels of vitamin D were associated with high levels of both testosterone and erectile function based on a questionnaire. After supplementation with vitamin D, testosterone levels increased and erectile function improved. Doses used for supplementation were either 1,250 mcg (50,000 IU) or 2,500 mcg (100,000 IU) given weekly, every two weeks, every three weeks, or monthly (7).
    • Testosterone: One small study on vitamin D deficient, overweight men undergoing a weight reduction program found that after one year of supplementation with 83.3 mcg (3,332 IU) per day, testosterone levels increased (5).

    What to look for in a good vitamin D supplement:

    As a supplement, vitamin D can come as either vitamin D2 (ergocalciferol) or vitamin D3 (cholecalciferol). The biggest difference between these two forms is how they are derived: vitamin D2 comes from plant sources while vitamin D3 usually comes from animal sources. Within the body, both are metabolized in similar ways and many consider them to be functionally equivalent. However, some research has indicated that supplementation with vitamin D3 may be better at raising and sustaining 25(OH)D levels (3,8). There is no difference between getting vitamin D from supplements, food, or sun exposure, as each of these raises 25(OH)D levels in the body (2).

    How much vitamin D is recommended?

    According to the Institute of Medicine and the National Institutes of Health, the Recommended Dietary Allowance (RDA) of vitamin D is 15 mcg (600 IU) per day for men and women ages 1–70. Men and women over age 70 should have 20 mcg (800 IU) per day. However, the Endocrine Society states that supplementation with 37.5–50 mcg (1,500–2,000 IU) per day may actually be more appropriate to maintain adequate blood levels of vitamin D (1). The RDA represents the daily amount of the vitamin that is considered sufficient to maintain bone health in healthy people. On the other end of the spectrum, the Tolerable Upper Intake Level (UL) for vitamin D is 100 mcg (4,000 IU) per day for both men and women over the age of 8 (2).

    What are the symptoms of having too little vitamin D?

    Exactly what qualifies as a vitamin D deficiency is not well defined. Most consider a normal 25(OH)D level to be above 50 nmol/L. Below 30 nmol/L is defined as a deficiency, while the range from 30–50 nmol/L is considered an insufficiency (9). One study that defined vitamin D deficiency with the higher cutoff of 50 nmol/L found that 39.92% of Americans are vitamin D deficient (4).

    The symptoms of having low vitamin D levels include bone pain and weakness but these are nonspecific. Severe vitamin D deficiency is classified as two different diseases: rickets and osteomalacia. Rickets is a disease that impacts children, causing skeletal deformities, bowing of the legs, and decreased bone density. Osteomalacia impacts adults, causing softer, weaker bones which may be more likely to break. Those at highest risk of developing vitamin D deficiency include breastfed infants, older adults, people with darker skin, people who spend limited time in the sunlight, people with anorexia nervosa, people with gastrointestinal issues that may impact absorption (such as inflammatory bowel disease, celiac disease, or prior gastric bypass surgery), and individuals with obesity.

    What are the symptoms of having too much vitamin D?

    It is unlikely to obtain too much vitamin D from food sources or from sunlight exposure. Instances of vitamin D toxicity, which are possible at 25(OH)D levels >500 nmol/L, likely result from taking high amounts of supplements. Ingesting more than the UL for vitamin D for extended periods of time can lead to adverse health effects. High levels of vitamin D lead to high levels of calcium in the blood, called hypercalcemia. This can cause calcification of the vasculature and of the tissues, leading to heart damage and kidney damage. It also increases the risk of developing kidney stones. Elevated levels of 25(OH)D have also been linked to an increase in all-cause mortality, pancreatic cancer, fractures, and falls in older adults. The symptoms of vitamin D toxicity include:

    • Not eating
    • Nausea
    • Vomiting
    • Abdominal pain
    • Constipation
    • Confusion
    • Frequent urination
    • Excessive thirst
    • Weight loss
    • Irregular heartbeat

    How does Roman offer vitamin D?

    Roman obtains vitamin D from non-GMO sources in China and India. It is available as vitamin D3 and is derived from lanolin from sheep wool.

    Roman offers vitamin D in the following supplements:

    Heart Health

    Vitamin D3 is one of seven main ingredients in Roman’s Heart Health supplement. The supplement consists of four tablets and two fish oil softgels that should be taken with water. Each individual tablet contains 12.5 mcg (500 IU) of vitamin D3, for a total daily dose of 50 mcg (2,000 IU). This level fulfills both the RDA and the Endocrine Society’s recommendations for daily vitamin D intake while staying below the UL.

    Other ingredients in the tablets include spirulina whole plant powder, deodorized garlic bulb powder, magnesium citrate, Coenzyme Q10, menaquinone-7, microcrystalline cellulose, dicalcium phosphate, stearic acid, croscarmellose sodium, magnesium stearate, silicon dioxide, and pharmaceutical glaze (shellac, povidone). Ingredients in the fish oil softgels include marine lipid concentrate, gelatin, glycerin, purified water, and mixed tocopherols. The softgels contain fish and should not be consumed by anybody with a fish allergy.

    Testosterone Support

    Vitamin D3 is one of six main ingredients in Roman’s Testosterone Support supplement. The supplement consists of four tablets that should be taken with water. Each individual tablet contains 12.5 mcg (500 IU) of vitamin D3, for a total daily dose of 50 mcg (2,000 IU). This level fulfills both the RDA and the Endocrine Society’s recommendations for daily vitamin D intake while staying below the UL.

    Other ingredients in the tablets include maca root powder, KSM-66® organic ashwagandha root extract, magnesium citrate, zinc sulfate, cupric oxide, microcrystalline cellulose, dicalcium phosphate, stearic acid, croscarmellose sodium, magnesium stearate, silicon dioxide, and pharmaceutical glaze (shellac, povidone).

    Does vitamin D interact with any other drugs or medical conditions?

    Vitamin D supplements can interact with certain medications. If you are taking any of the following medications, it is important you talk to your healthcare provider about your vitamin D intake (please note that this list may not be exhaustive and other medications may also interact with vitamin D) (2):

    • Corticosteroids: These medications can impair how the body processes both calcium and vitamin D, contributing to osteoporosis. An example of a corticosteroid is prednisone.
    • Orlistat: This weight-loss drug decreases the amount of vitamin A, D, E, and K that your body can absorb, so you may require supplementation.
    • Cholestyramine: This cholesterol-lowering drug decreases the amount of vitamin A, D, E, and K that your body can absorb, so you may require supplementation. To counteract this interaction, cholestyramine and vitamin D should be taken at different times of the day.
    • Seizure medications: Certain seizure medications changes how your body processes vitamin D, making more of it inactive. Examples of these seizure medications include phenobarbital and phenytoin.


    1. Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. The Journal of Clinical Endocrinology and Metabolism. 2011;96(7):1911-30. doi: 10.1210/jc.2011-0385.
    2. Office of Dietary Supplements – Vitamin D. NIH Office of Dietary Supplements. Accessed July 22, 2019.
    3. Oliveri B, Mastaglia SR, Brito GM, et al. Vitamin D3 seems more appropriate than D2 to sustain adequate levels of 25OHD: a pharmacokinetic approach. European Journal of Clinical Nutrition. 2015;69(6):697-702. doi:10.1038/ejcn.2015.16.
    4. Parva NR, Tadepalli S, Singh P, et al. Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012). Cureus. 2018. doi:10.7759/cureus.2741.
    5. Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann A. Effect of vitamin D supplementation on testosterone levels in men. Hormone and Metabolic Research. 2011;43(3):223-5. doi: 10.1055/s-0030-1269854.
    6. Spedding S. Vitamin D and Depression: A Systematic Review and Meta-Analysis Comparing Studies with and without Biological Flaws. Nutrients. 2014;6(4):1501-1518. doi:10.3390/nu6041501.
    7. Tirabassi G, Sudano M, Salvio G, Cutini M, Muscogiuri G, Corona G, Balercia G. Vitamin D and Male Sexual Function: A Transversal and Longitudinal Study. International Journal of Endocrinology. 2018;2018(12):1-8. doi: 10.1155/2018/3720813.
    8. Tripkovic L, Lambert H, Hart K, et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. SciVee. 2012. doi:10.4016/48110.01.
    9. UpToDate. Accessed July 22, 2019.
    10. Vacek JL, Vanga SR, Good M, Lai SM, Lakkireddy D, Howard PA. Vitamin D Deficiency and Supplementation and Relation to Cardiovascular Health. The American Journal of Cardiology. 2012;109(3):359-363. doi:10.1016/j.amjcard.2011.09.020.