Most people shopping for vitamin D expect to see one thing on the bottle: vitamin D.
So when you pick up a formula that pairs D3 with K2 and Omega-3, it’s natural to wonder exactly what those other two nutrients are doing and why they’re in the bottle.
They aren’t filler, and they aren’t different nicknames for the same compound. Vitamin D3, vitamin K2, and plant-derived omega-3 ALA belong to entirely distinct nutrient categories, and each plays its own role in normal physiology.
Understanding how they function—and why someone might want all three in a single daily routine—starts with breaking down what each ingredient actually does.
Let’s get into it.
The basics of vitamin D
Vitamin D is a fat-soluble nutrient that behaves a lot like a hormone once your body activates it. It plays an established role in normal immune function, muscle performance, and helping your digestive system absorb essential minerals like calcium and phosphorus.
When you look at dietary supplements or fortified foods, you’ll usually come across two distinct forms:
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Vitamin D2 (ergocalciferol): Primarily derived from plants or fungus.
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Vitamin D3 (cholecalciferol): The form naturally produced in your skin when exposed to sunlight.
Clinical research generally shows that vitamin D3 is more effective than D2 at raising and maintaining steady vitamin D concentrations in the bloodstream. For a deeper look at the biochemical differences between the two, the NIH Vitamin D Health Professional Fact Sheet has a thorough breakdown.
Where your body gets vitamin D
Under ideal conditions, your body makes its own vitamin D. When UVB rays hit bare skin, they trigger a chemical reaction that creates vitamin D3, which your liver and kidneys then convert into the active form your tissues can use.
In our busy daily lives, though, that process is rarely consistent. A variety of real-world factors—where you live, the season, your specific skin pigmentation, your age, and simply how many hours you spend indoors—all influence how much vitamin D your skin actually synthesizes.
Aside from sunlight, food is the other common way we take in vitamin D. Natural dietary sources are relatively limited, but they include fatty fish like salmon and mackerel, egg yolks, and certain UV-exposed mushrooms. Many people also rely on fortified foods, like cow’s milk, plant milks, and breakfast cereals.
Because fortification levels vary widely from brand to brand, checking the Supplement Facts or Nutrition Facts panel is the only reliable way to know how much vitamin D is in a given serving.
When regular sunlight and everyday meals don’t supply the intake someone is looking for, a standalone supplement provides a direct way to add vitamin D to a daily routine.
Why “fat-soluble” matters
Because vitamin D is fat-soluble, it dissolves in fat rather than water.
Having dietary fat present in the digestive tract can support how efficiently vitamin D is absorbed—even though your body can still take in some amount without it. That biological detail is why people are often advised to take vitamin D with a meal—and it’s the practical reason for formulating vitamin D alongside a healthy fat source.
Where vitamin K2 comes in
Vitamin K is its own essential nutrient family, and K2 (menaquinone) plays a specific role in how your body handles calcium.
While vitamin D helps your body absorb calcium from the foods you eat, vitamin K-dependent proteins help activate the processes that integrate calcium into bone tissue. People often compare K2 to a "traffic cop" for that reason: it participates in the natural signaling pathways that help direct calcium away from soft tissues and toward your bones and teeth. Pretty cool, right?
On a supplement label, you’ll typically see vitamin K2 listed under one of two primary forms: MK-4 or MK-7.
The letters stand for menaquinone, and the numbers represent the length of the molecular chain. That structural difference changes how the nutrient behaves after it has been ingested.
MK-4 (menaquinone-4) has a relatively short half-life in the bloodstream, meaning your body clears it quickly—often within a few hours. Because of that rapid clearance, formulas using MK-4 typically require multiple high-dose servings throughout the day to maintain steady circulating levels.
MK-7 (menaquinone-7), on the other hand, is a longer-chain menaquinone. That longer molecular chain allows it to remain in circulation significantly longer—often detectable in the bloodstream for up to 72 hours.
That brings us to the third ingredient in the trio: omega-3 ALA, the plant-derived fatty acid in the formula.
The role of Omega-3 (ALA)
Omega-3 isn’t a single compound—it’s an entire family of polyunsaturated fatty acids.
Passion 4 Health’s formula includes alpha-linolenic acid (ALA), an essential plant-based omega-3 fatty acid. Because your body cannot produce ALA on its own, it must come from your diet.
While your body can convert small amounts of ALA into the longer-chain omega-3s (EPA and DHA), ALA itself contributes directly to daily essential fatty acid intake.
In this formula, including plant-based ALA provides a fat base that complements a fat-soluble nutrient like D3, while keeping the source free of fish or marine oils. And that means no fishy burps!
Inside Passion 4 Health’s liquid formula
Passion 4 Health’s D3, K2 & Omega-3 Daily Liquid Vitamins was formulated for adults ages 18 and older who prefer a liquid over swallowing daily capsules or tablets.
Here’s what’s in each 1 mL serving:
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Vitamin D3: 125 mcg (5,000 IU).
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Vitamin K2: 120 mcg, provided as MK-7.
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Omega-3 Fatty Acids: 250 mg, provided as plant-based ALA from organic flaxseed oil.
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Organic Certification: Certified organic by Oregon Tilth.
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Clean Formulation: Non-GMO and made without added sugar, gelatin, artificial colors, or artificial flavors.
The liquid contains no added sweeteners or flavorings, and it carries a mild, naturally earthy taste similar to wheatgrass. You can drop it directly into your mouth using the measured dropper, or stir it into a glass of water, juice, or a morning smoothie. You can even drop it directly on your food.
Three nutrients, one simple routine
Choosing a liquid formula versus capsules or gummies ultimately comes down to personal routine, lifestyle, and format preference.
When you understand what D3, MK-7, and ALA actually represent, the label stops looking like a collection of random abbreviations and becomes much clearer. Each ingredient has an identifiable role, and having them in one bottle simply keeps your morning counter a little cleaner.
Frequently Asked Questions
Is vitamin D3 better than vitamin D2?
Vitamin D2 (ergocalciferol) is typically plant- or fungus-derived, while vitamin D3 (cholecalciferol) is the form your skin synthesizes when exposed to sunlight. Research indicates that vitamin D3 is more effective at raising and sustaining 25-hydroxyvitamin D concentrations in the body over time.
Why is vitamin D fat-soluble?
Fat-soluble nutrients dissolve in dietary fats and oils rather than water. Consuming vitamin D alongside a fat source helps support normal digestive absorption, which is why liquid formulas often pair vitamin D with fatty acids like plant-based ALA.
What dietary sources provide vitamin D?
Natural food sources include fatty fish (such as salmon, tuna, and mackerel), beef liver, egg yolks, and UV-treated mushrooms. Fortified foods, including cow's milk, soy milk, oat milk, and select breakfast cereals, also provide dietary vitamin D.
What does MK-7 mean on a vitamin K2 label?
MK-7 stands for menaquinone-7, which is a specific, highly stable form of vitamin K2. It is involved in activating proteins that help regulate calcium distribution in the body.
Which type of omega-3 is used in this formula?
This formula uses alpha-linolenic acid (ALA), an essential plant-derived omega-3 fatty acid. It provides a fish-free fatty acid base that supports the fat-soluble delivery of D3 and K2.
Is Passion 4 Health’s D3, K2 & Omega-3 formula vegan?
No. While the omega-3 ALA comes from plant sources, the vitamin D3 is derived from lanolin (sheep’s wool).
Who is this liquid formula designed for?
The formula is intended for adults ages 18 and older. It is designed for individuals who prefer a liquid supplement rather than swallowing tablets or capsules.
Does the liquid have an added flavor?
No artificial or natural flavors are added. The liquid has a subtle, natural grassy taste similar to wheatgrass.
This content is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with questions about a medical condition.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
