Look, I get why you're asking "what vitamin d should i take?" – it's confusing as hell. When I tried buying some last winter, I spent 45 minutes staring blankly at pharmacy shelves. D2 or D3? Liquid or capsule? 1000IU or 5000IU? And why do brands charge $10 for some bottles while others cost $40 for what looks like the same stuff?
After two years of researching this and talking to my doc (plus some trial-and-error), here's everything I wish someone had told me. No fluff, no scare tactics – just straight facts so you can pick what works for your body and wallet.
Why Vitamin D Actually Matters (Beyond the Hype)
Remember when everyone thought vitamin D was just for bones? Turns out it’s like your body’s orchestra conductor. Without enough:
- Your immune system gets clumsy (I caught 3 colds in 4 months before my levels were checked)
- Energy tanks worse than a phone at 5% (that 3pm slump? Could be D-related)
- Mood swings hit like uninvited guests (my husband called me "Sourpatch Sue" during my deficiency days)
Nearly 42% of US adults are deficient. Odds are high that includes you if you:
- Work indoors all day
- Live north of Atlanta (where winter sun is weaker)
- Have darker skin (melanin reduces D production)
- Are over 60 (skin makes less D as you age)
But here's the kicker: popping random supplements won't fix it if you're choosing wrong.
My doctor dropped this truth bomb: "Taking cheap vitamin D2 tablets when you're severely deficient is like using a teacup to drain a flooded basement." Changed my whole approach.
D2 vs D3: The Vitamin Showdown
Most people don't realize there are two types:
| Type | Source | Effectiveness | Best For |
|---|---|---|---|
| Vitamin D3 (Cholecalciferol) | Animal sources (fish oil, lanolin from wool), lichen (vegan) | Raises blood levels 87% better than D2, lasts longer in body | Most people (unless vegan/vegetarian avoiding animal products) |
| Vitamin D2 (Ergocalciferol) | Plant sources (mushrooms exposed to UV) | Less stable, requires higher doses to match D3 | Strict vegans (check labels though – some D3 is vegan!) |
Real talk: I used D2 for months because it was cheaper. Bloodwork showed minimal improvement. Switched to D3 – levels jumped in 8 weeks. Most experts agree: D3 is superior for raising vitamin D levels. Harvard Health and the NIH both recommend D3 supplements over D2.
Forms That Actually Work (And Ones That Don't)
Not all supplements are created equal. Here's what matters:
- Softgels/Liquid: Best absorption (vitamin D is fat-soluble). Brands like Now Foods and NatureWise use MCT oil capsules. I notice less stomach issues with these.
- Tablets: Cheaper but may not absorb well without food. Avoid if you have digestive issues.
- Gummies: Taste great but often contain sugar/gelatin. Dose accuracy can be sketchy – ConsumerLab found some brands had 50% less D than labeled.
- Sprays: Fast absorption under the tongue (like Garden of Life mykind spray). Great if you hate pills.
Red flag warning: Avoid "dry" D3 powders in capsules without oil. Vitamin D needs fat to be absorbed. Taking these without fatty food is like throwing money away.
How Much Vitamin D Should You Actually Take?
The generic "600-800 IU daily" recommendation? Often useless. Optimal dosing depends on:
| Current Blood Level | Body Weight | Recommended Daily Dose* |
|---|---|---|
| Severe Deficiency (<12 ng/mL) | Any | 5,000-10,000 IU for 3 months (under doctor supervision) |
| Moderate Deficiency (12-20 ng/mL) | <150 lbs | 3,000-5,000 IU daily |
| Moderate Deficiency (12-20 ng/mL) | 150-200 lbs | 5,000 IU daily |
| Mild Deficiency (20-30 ng/mL) | Any | 2,000-3,000 IU daily |
| Maintenance (30-50 ng/mL) | <150 lbs | 1,000-2,000 IU daily |
| Maintenance (30-50 ng/mL) | 150-200 lbs | 2,000 IU daily |
*Based on Endocrine Society guidelines. 1,000 IU raises blood levels by ~10 ng/mL in adults.
My personal protocol: 5,000 IU daily from October-April (I live in Chicago), then 2,000 IU in summer. Blood tests confirm I stay around 45 ng/mL.
Why Testing is Non-Negotiable
Guessing your dose is like driving blindfolded. Ask your doctor for:
- 25-hydroxyvitamin D test: The only accurate blood test (costs $40-$60 without insurance)
- Aim for 40-60 ng/mL – optimal range for most people
- Retest 3 months after starting supplements
Top Vitamin D Supplements I've Actually Tested
After trying 12+ brands, these deliver without breaking the bank:
| Brand & Product | Type | Dose per Serving | Price (360 servings) | Why It Stands Out | Drawbacks |
|---|---|---|---|---|---|
| NatureWise Vitamin D3 | Softgel (olive oil) | 5,000 IU | $16.99 ($0.04/serving) | Consistently high quality in tests, no soy/corn | Large softgels (some dislike swallowing) |
| Sports Research D3 (Costco version) | Softgel (coconut oil) | 5,000 IU | $19.99 for 600 ($0.03/serving) | Non-GMO, great absorption (coconut oil base) | Only at Costco or online |
| NOW Foods D-3 & K-2 | Softgel (fish gelatin) | 5,000 IU D3 + 100mcg K2 | $24.99 ($0.07/serving) | K2 directs calcium to bones (not arteries) | Fishy smell if capsule breaks |
| Garden of Life Vegan D3 Spray | Liquid spray (lichen) | 1,000 IU per spray | $24.99 ($0.14/serving) | Best vegan option, no swallowing needed | Higher cost per dose |
Overhyped brand I regret buying: MegaFood D3. Claims to be "food-based" but contains only 1,000 IU per $0.50 tablet. Felt like paying for marketing.
Must-Have Combo: Vitamin D3 + K2
Taking high-dose D without K2? Risky move. Vitamin K2 (specifically MK-7 form) prevents calcium from clogging arteries. Studies show D3+K2 supplementation:
- Improves bone density 1.5x better than D alone
- Reduces arterial stiffness by 12% in 3 months
- Optimal ratio: 100-200mcg K2 per 5,000 IU D3 (like in NOW Foods combo)
Critical Mistakes That Waste Your Money
I learned these the hard way:
- Taking D with coffee/breakfast: Caffeine reduces absorption by 30%. Take it with lunch/dinner instead.
- Storing bottles in bathroom: Heat and humidity degrade potency. Keep in cool, dark pantry.
- Buying "mega-dose" 50,000 IU pills: Only for weekly medical therapy – daily use causes toxicity.
- Ignoring magnesium: Magnesium activates vitamin D. Take 300mg magnesium glycinate if deficient.
Real People Questions (What Vitamin D Should I Take Edition)
Can I just get vitamin D from sunlight?
Maybe. If you’re fair-skinned, live in Florida, and sunbathe daily in shorts? Possibly. But most office workers get maybe 10% of what they need. SPF 15 blocks 99% of UVB rays needed for D production. Realistically? Supplement.
Why do some vitamin D supplements make me feel nauseous?
Usually one of three reasons: 1) You're taking it on an empty stomach (always pair with food), 2) Cheap fillers/binders irritate your gut (switch brands), or 3) You're sensitive to the oil base (try coconut oil instead of soybean). Happened to me with CVS brand – switched to Sports Research, problem gone.
Are expensive "medical-grade" brands better?
Often not. ConsumerLab tested 47 supplements – no correlation between price and quality. Even Kirkland Signature (Costco) passed purity/accuracy tests. Pay for third-party testing (USP, NSF, Informed Choice), not fancy labels.
How long until I feel benefits?
Timeline varies: Energy improvements in 2-4 weeks, immune benefits in 3 months, bone density changes take 6+ months. Consistency is key – set a phone reminder if you forget doses.
The Final Checklist Before You Buy
When deciding what vitamin d should i take, run through this:
- Form: Softgel or liquid with oil base? (✓ Yes / ☐ No)
- Type: D3 (not D2) unless vegan? (✓ Yes / ☐ No)
- Dose: Matches your blood test needs? (✓ Yes / ☐ No)
- Combo: Includes K2 (MK-7) if taking >2000 IU? (✓ Yes / ☐ No)
- Testing: Third-party certification on label? (✓ Yes / ☐ No)
- Value: Cost per dose <$0.10? (✓ Yes / ☐ No)
At the end of the day, the best vitamin D supplement is the one you'll actually take consistently. Start with a solid mid-range option like NatureWise or NOW Foods, test in 3 months, and adjust. Your energy levels will thank you by next season.
A Quick Reality Check
No vitamin D supplement will fix terrible sleep or a junk food diet. But combined with decent lifestyle habits? It’s the closest thing to a magic bullet I’ve found in 15 years of health blogging. Just don’t expect overnight miracles – this is a long game.