THE PROMISE
5,000 IU of high-potency D3. The superior form — not the cheaper D2.
Vitamin D deficiency is one of the most widespread nutritional deficiencies in the developed world — driven by indoor lifestyles, sunscreen use, and limited dietary sources. Ultimate Vitamin D3 delivers a clinical-strength 5,000 IU dose of cholecalciferol — the D3 form your body naturally produces and uses far more effectively than the cheaper D2 (ergocalciferol) found in mass-market brands. Paired with organic coconut oil to maximize intestinal absorption and ensure every microgram actually reaches your bloodstream.
High-Potency
High-potency Vitamin D3 (cholecalciferol) — the same form produced by human skin upon sun exposure, and the form the body uses most efficiently. Not the cheaper D2 (ergocalciferol) used to fortify foods and found in mass-market supplements, which raises blood levels far less effectively and fades faster.
Coconut Oil
Vitamin D is fat-soluble — it requires dietary fat to be absorbed through the intestinal wall. We add certified organic coconut oil directly into each softgel to provide the lipid matrix needed for maximum absorption without requiring a separate meal.
Lanolin-Derived
Our Vitamin D3 is derived from lanolin — extracted from the wool of healthy, living sheep in Australia and New Zealand. This is the same source used in the most clinically studied vitamin D supplements, and the most bioidentical form to human skin-produced D3.
Practitioner-Selected
Manufactured under strict GMP protocols ensuring standardized 5,000 IU potency in every softgel, with a Certificate of Analysis available for every batch. Hand-selected by Dr. Devin Ryerson — chosen over other options for its superior cholecalciferol form and lanolin sourcing, and a supplement he personally takes every day.
WHY IT WORKS
Four systems, one high-potency vitamin.
Bone Density & Calcium Metabolism
Vitamin D3 is essential for calcium absorption in the intestine — without adequate D3, the body absorbs as little as 10–15% of dietary calcium. Optimal D3 levels increase calcium absorption to 30–40%. D3 also regulates osteocalcin and calcium-binding proteins critical for bone matrix mineralization and long-term skeletal density.*
Immune System Regulation
Vitamin D receptors (VDR) are present on virtually every immune cell. D3 activates macrophages, regulates T-cell function, and modulates the inflammatory response. Clinical research links deficiency to impaired immune surveillance and increased susceptibility to respiratory challenges. 5,000 IU daily is a commonly studied dose for immune support.*
Mood, Cognitive Function & Seasonal Wellness
Vitamin D receptors are densely expressed throughout the brain, including regions governing mood regulation. Research shows a consistent association between low D3 levels and seasonal mood changes, cognitive wellness, and overall sense of wellbeing. Correcting deficiency is one of the most impactful nutritional interventions for mood.*
Cardiometabolic & Cellular Health
Beyond skeletal health, vitamin D3 supports healthy blood pressure, glucose metabolism, insulin sensitivity, and anti-inflammatory balance — a multi-system role now recognized as "cardiometabolic health." It also plays a role in cellular differentiation and healthy cell cycle regulation.*
Customer Reviews
Tried, tested,
truly loved.
YOUR PROTOCOL
When to take it,
and why it matters
One softgel daily, ideally with a meal. The organic coconut oil inside each softgel provides the absorption vehicle — but pairing with dietary fat maximizes results.* Consistent daily use over 8–12 weeks is required to meaningfully raise blood 25(OH)D levels.*
Take one softgel with breakfast, ideally a meal containing some dietary fat (eggs, avocado, full-fat yogurt). Although the built-in coconut oil provides a lipid matrix, a fatty meal further optimizes absorption and extends the time D3 metabolites remain elevated in the bloodstream.*
WHY IT WORKS
Vitamin D3 absorption follows the fat-soluble pathway: emulsification by bile, packaging into chylomicrons, and lymphatic transport. Fat at the meal amplifies each of these steps. The coconut oil in the softgel initiates this process even without dietary fat.*
Many people assume they get enough D3 in summer. In reality, sunscreen, clothing coverage, glass (which blocks UV-B), and spending peak hours indoors means even summer sun exposure is insufficient for most people. Testing your 25(OH)D level with your physician is the only way to know for certain.
WHY IT WORKS
Optimal 25(OH)D levels (40–60 ng/mL by integrative standards) require consistent daily supplementation for most people year-round — not just winter months.* Studies show deficiency is prevalent even in sunny climates due to modern indoor lifestyles.
Vitamin D3 is converted to its active form (calcitriol) by enzymes that require magnesium as a cofactor. Magnesium deficiency — extremely common in the US — limits how effectively D3 supplementation can work.* Pairing our Magnesium Glycinate with Ultimate Vitamin D3 maximizes the clinical benefit of both.*
WHY IT WORKS
Clinical research confirms that magnesium regulates vitamin D metabolism at multiple enzymatic steps. Supplementing D3 without adequate magnesium produces suboptimal blood 25(OH)D responses — this is a frequently overlooked aspect of vitamin D supplementation.*
SUGGESTED USE
One softgel. With breakfast. Every day.
Take 1 softgel daily with a meal. Do not exceed the recommended amount except under the advice of your physician. Monitor 25(OH)D blood levels annually.
What's Inside
What's inside,
and why it matters.
The sunshine vitamin — in its most potent, body-ready form.
Cholecalciferol is Vitamin D3 — the identical form synthesized by human skin upon UV-B exposure and the form the body converts most efficiently to its active hormone (calcitriol). Unlike the cheaper Vitamin D2 (ergocalciferol) found in mass-market supplements, D3 raises blood 25(OH)D levels far more effectively and sustains them longer — the form your body was designed to use.* Derived from lanolin — extracted from the wool of healthy sheep in Australia and New Zealand — the most bioidentical non-skin source available.
Vitamin D3 (Cholecalciferol) · 5,000 IU (125 mcg) · 625% Daily Value · Lanolin-derived · Australia/New Zealand
Lanolin · Australia & New Zealand
The absorption matrix — not a filler.
Vitamin D3 is fat-soluble, meaning it requires dietary lipids for intestinal absorption. Without fat co-ingestion, absorption is dramatically reduced.* We add certified organic coconut oil directly into each softgel — providing the lipid matrix that triggers bile secretion and maximizes D3 absorption through the lymphatic pathway, regardless of whether it's taken with a meal.*
Certified Organic Coconut Oil (Cocos nucifera) · Medium-chain triglycerides · USDA Organic
Organic Coconut Oil · USDA Certified
Dr. Devin Ryerson
Founder & Chief Curator · Est. 1999Why It Matters
Built by someone with
personal stakes in it.
Devin started Pure Prescriptions in 1999 after battling Hodgkin's Lymphoma and losing his father to leukemia. That experience made him the most stubborn kind of formulator — one who refuses to ship anything he wouldn't take himself.
Every ingredient here earned its place through clinical evidence, third-party testing, and that same personal lens — the five collagen types, the organic fruiting-body mushrooms, the co-factors. Nothing is decorative.
"Pure Prescriptions has always been more personal than corporate. Built by family. Still independent."
Our StoryYour Journey
What to expect
Vitamin D works by raising blood levels gradually. Here's the clinical evidence of what changes over time.
WEEK 1–4
D3 Levels Begin Rising
Blood 25(OH)D levels begin rising as supplemental D3 is absorbed and converted. Organ and tissue uptake follows plasma levels. Some users notice early mood and energy improvements as D3 receptors in the brain and nervous system are activated.
BLOOD LEVELS RISING
WEEK 4–8
Immune & Mood Benefits
Immune cell vitamin D receptor activation becomes meaningful. T-cell regulation and macrophage function improve. Users commonly notice improved mood stability and energy, particularly those supplementing in winter or with prior deficiency. Bone metabolism markers begin shifting.
IMMUNE · MOOD ACTIVE
WEEK 8–12
Calcium & Bone Metabolism
Intestinal calcium absorption is meaningfully improved as vitamin D receptor signaling in enterocytes reaches steady-state. Bone formation markers (osteocalcin, alkaline phosphatase) begin reflecting improved mineral deposition. First checkpoint to test blood levels with physician.
CALCIUM ABSORPTION · BONE
WEEK 12+
Sustained Optimal Status
Blood 25(OH)D levels stabilize at a new optimal range. Full multi-system benefits are active: bone density maintenance, immune surveillance, cardiometabolic support, and mood regulation. Continued daily supplementation maintains these levels — stopping causes gradual decline back to deficiency.
OPTIMAL D3 STATUS MAINTAINED
TEST BLOOD LEVELS WITH YOUR PHYSICIAN · RESULTS REQUIRE CONSISTENT DAILY USE
Results vary from person to person.
The Science
Why D3 without fat
isn’t actually working.
Vitamin D3 is fat-soluble. Without a lipid vehicle, a significant portion of each dose passes through the gut unabsorbed — explaining why many people supplement consistently yet fail to raise blood 25(OH)D levels into the optimal range. Ultimate Vitamin D3 solves this with organic coconut oil built directly into each softgel.
- 5,000 IU D3 per softgel — clinical-strength dose
- D3 (cholecalciferol) — not D2 — the body-ready form
- Organic coconut oil co-delivered for maximum absorption
- Lanolin source from healthy sheep in Australia & New Zealand
5,000 IU · Cholecalciferol · Organic Coconut Oil
Have Questions?
Everything you need to know.
Honest answers — no marketing spin. If your question isn’t here, our team responds within one business day.
1,000 IU is insufficient for most adults to correct deficiency or maintain optimal blood 25(OH)D levels (generally considered 40–60 ng/mL by integrative practitioners). Studies show that most vitamin D-deficient adults require 4,000–6,000 IU daily to reach and maintain optimal levels. 5,000 IU is a well-established therapeutic dose used in clinical practice. Always test your levels with your physician to confirm appropriate dosing.
Vitamin D3 is fat-soluble — it requires dietary fat for intestinal absorption. Without a lipid co-delivery mechanism, much of a vitamin D capsule or tablet passes through the gut unabsorbed. By including organic coconut oil directly in the softgel, we ensure maximum absorption occurs regardless of whether you take it with a meal. This is not a filler — it is a clinically important absorption strategy.
Vitamin D3 (cholecalciferol) is the form produced by human skin upon UV-B exposure and is the form shown in research to raise blood 25(OH)D levels more effectively and sustain them longer than D2 (ergocalciferol). D2 is cheaper and used to fortify many foods, but D3 is the clinically superior form for supplementation and is the form used in all meaningful vitamin D research.
Our D3 is derived from lanolin — a natural wax from sheep’s wool, extracted from healthy living sheep in Australia and New Zealand. This is the most widely used and best-studied source of supplemental D3, and is considered the most bioidentical non-skin source available. The sheep are not harmed in the collection process.
Although the organic coconut oil in each softgel provides the lipid matrix needed for absorption, taking it with a meal that contains some fat will provide additional benefit. It can be taken with or without food due to the built-in coconut oil, making it more convenient than D3 tablets or capsules that require a fatty meal for absorption.
Ultimate Vitamin D3 pairs extremely well with our Magnesium Glycinate (magnesium is required for vitamin D activation and calcium regulation), Perfect Collagen (bone matrix building), and Daily Multivitamin (provides Vitamin K2, which directs calcium into bone rather than arteries — important when taking high-dose D3).
Doctor’s Protocol
How I’d build your bone & immune foundation.
“Vitamin D3 is the most important micronutrient most people are missing. Magnesium is essential to activate it. Collagen provides the bone matrix D3’s calcium fills. The multivitamin provides K2 to direct calcium safely into bone. Together these form the most clinically grounded bone and immune protocol I know.”
In Order of Priority
4 Products · 1 Protocol
Doctor's First Choice
Ultimate Vitamin D
Start here. 5,000 IU Vitamin D3 with organic coconut oil for maximum absorption — the most common nutritional deficiency, supported with 1-2 daily softgels.
D3 Activation · Bone · Vascular
Magnesium Glycinate
Magnesium is required for the enzymatic activation of Vitamin D3 into calcitriol. Magnesium deficiency limits how effectively D3 supplementation raises blood levels. Additionally, both regulate bone mineralization through independent pathways — together they form the backbone of bone health supplementation.
Bone Matrix · Skin · Longevity
Perfect Collagen®+ Vitamin C
Vitamin D3 promotes calcium absorption and mineralization while Collagen provides the organic matrix into which calcium deposits — bone is 30% collagen and 70% mineral. Without adequate collagen, even optimal calcium and D3 supplementation cannot produce maximum bone density.
Vitamin K2 · Complete Micronutrients
Daily Multivitamin
High-dose Vitamin D3 increases calcium absorption — Vitamin K2 (in our multivitamin) is required to direct that calcium into bone rather than arteries. This is the most important co-factor when taking 5,000 IU D3 daily. K2 activates osteocalcin and MGP — the proteins that control calcium's destination.
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