---
title: "Vitamin D 400 Iu — $121K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/health-household/vitamin-d-400-iu"
last_updated: "2026-08-09T21:47:45.654Z"
locale: en
meta:
description: "Niche score 46/100 · $121K/yr market · 93K searches/yr · $11.42 avg price. Doesn't clear our bar today. Data updated Aug 2026."
"og:description": "Niche score 46/100 · $121K/yr market · 93K searches/yr · $11.42 avg price. Doesn't clear our bar today. Data updated Aug 2026."
"og:title": "Vitamin D 400 Iu — $121K/yr Amazon US Niche (2026) - Flapen"
---
# **vitamin d 400 iu**
**Skip it**
A deep review moat (16,363 avg reviews) — this niche doesn't clear our bar today.
Market size 28Growth 30Conversion 93Competition 41Returns 100Price range 28Avg price 45Brand share 59Review moat 18Quality gap 19
**Returns**
**Incredible****0.0%**
return rate — above 5% kills the launch gate
**Conversion**
**Great****11.4%**
search→purchase rate — share of searches ending in a sale
**Brand share**
**Good****70%**
top-5 brand share — brands hold most of the demand
**Avg price**
**Okay****$11.42**
avg listing price — sweet spot $15–$100
**Competition**
**Okay****60%**
top-5 click share — leaders hold, buyers still browse
**Growth**
**Okay****+3.8%**
90-day search growth — must beat 0% to launch
**Market size**
**Okay****$121K**
$121K/yr · 93K searches
**Price range**
**Okay****$4.86–$18.97**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Quality gap**
**Bad****4.7★**
avg incumbent rating — lower means beatable quality
**Review moat**
**Bad****16,362.77**
avg incumbent reviews — the moat a new listing must climb
According to Flapen's Amazon United States niche tracking, vitamin d 400 iu is a $121K/yr Amazon United States market (93K searches/yr). The top 5 brands hold 70% of demand. Demand peaks in May–Jul. Verdict: Skip it — 46/100.
Data updated Aug 5, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **vitamin d 400 iu market data**
- **Units sold / yr**
- **13K–15K**
- avg 750–1,000/product
- **Revenue / yr**
- **$143K–$171K**
- units × avg price
- **Conversion rate**
- **11.4%**
- **Avg BSR**
- **#609**
- **Page quality**
- **0%**
- **Prime**
- **91%**
- **Sponsored**
- **68%**
- **Out of stock**
- **0.0%**
- **Avg brand age**
- **101 months**
- **Avg seller age**
- **154 days**
## **Competition & brand share**
The top 5 products take 60% of clicks — established leaders, but buyers still shop beyond them.
**Brands**
**16 **▲rising
**Sellers**
**111**
**Top-5 brand share**
**70%**
Top 20: 100%
**Top-5 click share**
**60%**
Top 20: 98%
**Open market**
**24%**
- Nature's Truth26% - NOW Foods17% - Carlyle11% - Swanson8% - Pure Encapsulations7% - Nature Made7%
## **Demand & seasonality**
Weekly Amazon search volume, last 101 weeks — +3.8% search growth over the last 90 days.
2K2KSpike '24Spike '25Spike '26 seasonDecMarJunAugNovMarMay
Peak months: May, Jul · busiest ÷ quietest = 1.7×
[**Open Trend **](https://flapen.com/research/us/health-household/vitamin-d-400-iu/trend)
## **Top vitamin d 400 iu search terms**
- **vitamin d 400 iu**18K/yr+11.5%11.2% conv. - **vitamin d3 400 iu**16K/yr+7.4%13.7% conv. - **vitamin d3 400iu**8K/yr+48.6%6.3% conv. - **vitamin d 500 iu**9K/yr-3.4%6.5% conv. - **vitamin d3 500 iu**5K/yr+1.3%8.4% conv. - **vitamin d 500**5K/yr-4.6%4.4% conv. - **low dose vitamin d**5K/yr-13.5%9.8% conv. - **d3 400 iu**4K/yr-1.0%21.1% conv. - **vitamin d 400**3K/yr+3.3%13.1% conv. - **natures truth d3**3K/yr+0.9%14.2% conv. [**All search terms **](https://flapen.com/research/us/health-household/vitamin-d-400-iu/search-terms)
## **Top vitamin d 400 iu products on Amazon**
Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
0%10%$12K20%$24K30%$36K40%$48K101001K10K100K1.0M Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 22 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**Natures Truth Vitamin D3 400 IU 100 Count**Nature's Truth**$6.85**4.7★1,046 rev](https://www.amazon.com/dp/B06X9DZ325) [2**NOW Supplements Vitamin D-3 400 IU Strong Bones* Structural support* 180 Softgels**NOW Foods**$4.86**4.7★5,350 rev](https://www.amazon.com/dp/B000V7EIH8) [3**Carlyle Vitamin D3 400iu (10mcg) | 400 Tablets | Value Size**Carlyle**$9.19**4.7★374 rev](https://www.amazon.com/dp/B09F3TS42V) [4**Pure Encapsulations Vitamin D3 10 mcg (400 IU) | Hypoallergenic Support for Bone Breast Cardiovascular Colon and Immune Health* | 120 Capsules**Pure Encapsulations**$18.01**4.6★306 rev](https://www.amazon.com/dp/B0017OGB10) [5**Swanson Vitamin D3 Bone Health 400 IU (10 mcg) 250 Capsules**Swanson**$7.44**4.4★56 rev](https://www.amazon.com/dp/B001TEKOFW)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**Bronson Vitamin D3 1000 IU (25mcg) Low Dose Vitamin D 360 Tablets**Bronson**$9.85**93 rev7mo ago](https://www.amazon.com/dp/B0G7L2TSF7) [**Vitamin D3 10 mcg (400 IU) 200 Softgels - Dietary Supplement (Pack of 1)**Unique Bundle Store**$15.01**50 rev2y ago](https://www.amazon.com/dp/B0CNW4CFCK) [**Natures Truth Vitamin D3 5000 IU Softgels | 400 Count | High Potency | Non-GMO & Gluten Free Supplement**Nature's Truth**$18.97**325 rev3y ago](https://www.amazon.com/dp/B0CBSXC4ZB) [**Natures Truth Vitamin D3 Gummies | 5000 IU | 60 Count | Peach Flavor | Vegetarian Non-GMO & Gluten Free Supplement**Nature's Truth**$9.89**795 rev4y ago](https://www.amazon.com/dp/B09TS27BRZ) [**Carlyle Vitamin D3 400iu (10mcg) | 400 Tablets | Value Size**Carlyle**$9.19**374 rev4y ago](https://www.amazon.com/dp/B09F3TS42V)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**Bronson Vitamin D3 1000 IU (25mcg) Low Dose Vitamin D 360 Tablets**Bronson**$9.85**4.7★**▲ 216%**](https://www.amazon.com/dp/B0G7L2TSF7) [**Swanson Vitamin D3 Bone Health 400 IU (10 mcg) 250 Capsules**Swanson**$7.44**4.4★**▲ 100%**](https://www.amazon.com/dp/B001TEKOFW) [**NOW Foods Vitamin D-3 400 IU Softgels 2 pk 180 Count (Pack of 2)**NOW Foods**$11.03**4.7★**▲ 79%**](https://www.amazon.com/dp/B00J11LM4W) [**Nature Made Vitamin D3 1000 IU (25 mcg) 180 Vitamin D Softgels**Nature Made**$8.67**4.8★**▲ 46%**](https://www.amazon.com/dp/B004U3Y8SI) [**Natural Nutra Vitamin D3 400 IU Softgels Gluten-Free Vitamin D 100 Count**Natural Nutra**$15.05**4.6★**▲ 45%**](https://www.amazon.com/dp/B00TIY7674)
**~~View all trending →~~**
## **What buyers say about vitamin d 400 iu**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Vitamin**18%
*“Quality vitamins”*
**Quality-Overall**15%
*“the quality seems consistent”*
**Value For Money**14%
*“fair price”*
**Ease Of Use**9%
*“Easy peasy”*
**Advertised Vs Actual Product**7%
*“accurately described”*
**Ease Of Chewing/Swallowing**6%
*“Tastes great and is easy to chew”*
**Dosage**5%
*“The dropper makes dosing straightforward”*
**Efficiency**3%
*“very effective”*
**Taste-Overall**1%
*“It doesnt seem to change the taste of the milk so she drinks it just fine”*
**Vegan/Organic**1%
*“I like the usda organic certification”*
### **What buyers complain about **
**Leak-Proof**10%
*“leaking issue”*
**Size-Overall**8%
*“Very small bottle size”*
**Dosage**6%
*“Its a very low dose”*
**Vitamin**6%
*“Not normal vitamin smell, more rancid”*
**Taste-Overall**4%
*“Doesn't taste like anything”*
**Functionality-Overall**4%
*“Cant provide results yet”*
**Advertised Vs Actual Product**3%
*“Bottle is different from the box”*
**Quality-Overall**3%
*“Not high quality”*
**Smell**2%
*“Doesnt smell like anything”*
**Dispensing Mechanism**2%
*“Not an easy disoenser”*
### **Top return reasons **
**Vitamin**17%
**Dosage**17%
**Value For Money**11%
**Ingredients-Overall**11%
**Functionality-Overall**11%
**Smell**6%
**Dispensing Mechanism**6%
**Age Suitability**6%
**Advertised Vs Actual Product**6%
**Oily/Greasy**6%
## **Common questions**
- **Is vitamin d 400 iu profitable to sell on Amazon United States?**
- The niche generates $121K/yr across 22 tracked products. 1 of 1 products launched in the last 360 days are still selling. 90-day search growth is +3.8%. Flapen's verdict: Skip it (46/100).
- **How competitive is the vitamin d 400 iu niche?**
- 16 brands and 111 sellers compete. The top 5 products take 60% of clicks and top 5 brands hold 70% of demand.
- **What do buyers complain about in vitamin d 400 iu?**
- Top complaints mined from reviews: Leak-Proof, Size-Overall, Dosage. The return rate is 0.0%.
- **When does demand for vitamin d 400 iu peak?**
- Demand peaks in May–Jul; the busiest month runs 1.7× the quietest.
- **What does it cost to enter the vitamin d 400 iu niche?**
- Listings span $4.86–$18.97; the average listing price is $11.42 (sweet spot $15–$100). The average incumbent carries 16,363 reviews — the moat a new listing must climb.
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