What is prescription vitamin D made from?

According to the National Institutes of Health, vitamin D deficiency is a major public health concern, but understanding exactly what is prescription vitamin D made from can provide valuable insight into treatment options. Prescription-strength vitamin D is formulated using high-potency versions of either vitamin D2 or D3, derived from specific industrial processes involving different starting materials to correct severe deficiencies.

Quick Summary

Prescription vitamin D consists of either vitamin D2 (ergocalciferol), derived from UV-irradiated yeast, or vitamin D3 (cholecalciferol), which is typically synthesized from lanolin (sheep's wool) or lichen. These raw materials are chemically processed and irradiated to create potent pharmaceutical-grade compounds.

Key Points

• Two Primary Forms: Prescription vitamin D is available as either ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3).

• D2 is Plant-Based: Vitamin D2 is manufactured exclusively from ergosterol, a compound found in yeast and fungi, which is exposed to UV light.

• D3 Can Be Animal or Vegan: Vitamin D3 is traditionally made from lanolin (sheep's wool), but vegan-friendly versions derived from lichen or algae are also used for synthesis.

• Industrial Synthesis: Both forms are produced through a chemical process involving UV irradiation of a precursor steroid, followed by extensive purification for medicinal use.

• D3 Shows Greater Potency: Clinical studies indicate that vitamin D3 is more effective than D2 at increasing and sustaining serum vitamin D levels.

• Source Impacts Suitability: The source material affects suitability for those with dietary restrictions; D2 is always vegan, while D3 requires specific sourcing (lichen) to be vegan.

The Two Forms of Prescription Vitamin D

Before delving into its manufacturing, it's important to know that prescription vitamin D comes in two main forms: vitamin D2, known as ergocalciferol, and vitamin D3, known as cholecalciferol. While the body can synthesize vitamin D3 naturally from sunlight, pharmaceutical versions are created from specific industrial-scale processes. The choice between D2 and D3 for a prescription often depends on various factors, including potency, cost, and patient dietary restrictions. For example, D2 is always plant-derived and vegan-friendly, whereas D3 is traditionally animal-sourced but can now also be produced from lichen for vegan formulations.

The Production of Prescription Vitamin D2 (Ergocalciferol)

Prescription-grade vitamin D2 is produced entirely from plant-based sources, primarily yeast. The process utilizes ergosterol, a steroid found in the cell membranes of fungi and yeast, as a precursor. The manufacturing involves exposing the yeast-derived ergosterol to ultraviolet (UV) light. This irradiation process chemically converts the ergosterol into previtamin D2, which then isomerizes into the final product, ergocalciferol. After irradiation, the resulting product undergoes a series of purification steps to isolate and concentrate the pharmaceutical-grade vitamin D2, ensuring high potency and purity for medicinal use.

Step-by-Step Production Process for Vitamin D2

The synthesis of ergocalciferol follows a defined industrial procedure:

• Source Acquisition: Ergosterol is extracted from yeast or fungi cultures.
• Ultraviolet Irradiation: The purified ergosterol is exposed to controlled doses of UV light, breaking a chemical bond and converting it into previtamin D2.
• Isomerization: The previtamin D2 undergoes a thermal isomerization process to transform into the stable ergocalciferol.
• Purification: The resulting mixture is purified to remove unwanted byproducts and isomers, leaving a highly concentrated and pure vitamin D2 resin.
• Formulation: The resin is formulated into the final prescription product, such as oral capsules or liquid drops.

The Production of Prescription Vitamin D3 (Cholecalciferol)

In contrast to vitamin D2, the industrial synthesis of cholecalciferol historically relied on animal sources, though vegan alternatives now exist. The most common source is lanolin, a waxy substance derived from sheep's wool. Cholesterol is first extracted from the lanolin, which is then processed to create 7-dehydrocholesterol. This compound is the same precursor our skin uses to make vitamin D3 naturally. The 7-dehydrocholesterol is then irradiated with UV light and purified to yield cholecalciferol. For vegan-friendly prescription options, vitamin D3 can be produced from certain species of lichen and algae, which also produce cholecalciferol when exposed to sunlight. This provides a non-animal source for patients with dietary restrictions.

The Lanolin-Based Process for Vitamin D3

• Wool Greese Extraction: Lanolin is obtained from the washing of sheep's wool after shearing.
• Cholesterol Refinement: The lanolin is processed to extract cholesterol.
• Chemical Conversion: A multi-step chemical conversion process transforms the cholesterol into the precursor, 7-dehydrocholesterol.
• UV Irradiation: The 7-dehydrocholesterol is then exposed to UV light to create cholecalciferol.
• Purification: A final purification removes any unwanted isomers and impurities.

The Vegan-Friendly Process for Vitamin D3

• Lichen/Algae Sourcing: Specific strains of microalgae or lichen are cultivated.
• UV Exposure: These organisms are exposed to UV light, which triggers their natural production of cholecalciferol.
• Extraction and Purification: The cholecalciferol is extracted and purified from the plant material to meet pharmaceutical standards.

Comparison of Prescription Vitamin D2 and D3

Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Starting Material	Ergosterol, derived from yeast/fungi.	7-dehydrocholesterol, derived from lanolin (sheep's wool) or lichen.
Source	Always plant/fungal-based, making it suitable for vegans and vegetarians.	Historically animal-based (lanolin), but vegan options from lichen/algae are now common.
Metabolic Potency	Often considered less potent and with a shorter duration of action than D3 in raising serum vitamin D levels.	More effective at increasing and sustaining serum vitamin D concentrations.
Manufacturing Method	UV irradiation of ergosterol.	UV irradiation of 7-dehydrocholesterol.
Prescription Availability	Widely available in high-potency prescription forms.	Increasingly common in prescription forms due to superior effectiveness.

Conclusion: The Final Form of Your Prescription

Regardless of whether a prescription is for vitamin D2 or D3, the process to create the final medicinal product involves controlled industrial synthesis from specific raw materials. Whether starting with yeast-based ergosterol or lanolin/lichen-based 7-dehydrocholesterol, the key step involves ultraviolet irradiation to create the final inactive vitamin compound. This compound is then purified and formulated into the prescribed medication. After ingestion, the body's liver and kidneys perform further conversions to activate the vitamin, allowing it to regulate calcium and phosphate metabolism and support overall health. The fundamental origins of the molecule, whether plant-derived D2 or animal/lichen-derived D3, are key to understanding the specific medication. For a deeper dive into the metabolic pathways involved in activating vitamin D, explore reputable resources like those from the National Institutes of Health.

Frequently Asked Questions

What is the main difference between prescription vitamin D2 and D3?

The main difference lies in their source material and manufacturing. Vitamin D2 (ergocalciferol) comes from plant-based ergosterol, while vitamin D3 (cholecalciferol) is typically derived from animal-sourced lanolin or vegan-friendly lichen.

Is prescription vitamin D vegan?

It depends on the form. All vitamin D2 prescriptions are vegan, as they are derived from yeast. For a vegan prescription of vitamin D3, the pharmaceutical company must specify that it is sourced from lichen, not lanolin.

Where does the lanolin for vitamin D3 production come from?

Lanolin is a natural waxy substance found on sheep's wool. After shearing, the wool is washed, and the wool grease is collected. This lanolin is then used to extract the cholesterol needed to create vitamin D3.

Is vitamin D2 or D3 more effective for raising blood vitamin D levels?

Multiple studies and a meta-analysis have indicated that vitamin D3 is generally more effective at raising and maintaining serum vitamin D levels than vitamin D2, though both are used to treat deficiency.

Can I tell what my prescription vitamin D is made from just by looking at the label?

The active ingredient name on the label will specify if it is ergocalciferol (D2) or cholecalciferol (D3), indicating its source class (yeast vs. animal/lichen). However, for specific vegan D3, you may need to consult the manufacturer.

Why is UV light used to create prescription vitamin D?

UV irradiation is used to mimic the natural process by which the body and certain plants produce vitamin D. It triggers the chemical conversion of the precursor molecules (ergosterol or 7-dehydrocholesterol) into the desired vitamin D compound.

Do over-the-counter vitamin D supplements use the same sources?

Yes, over-the-counter supplements also use D2 from yeast or D3 from lanolin or lichen. The main difference between supplements and prescription medication is the potency, as prescriptions are typically much higher doses.