vitamin d 400iu
Skip itA concentrated shelf (top 5 take 100% of clicks) — this niche doesn't clear our bar today.
Returns
Incredible0.0%return rate — above 5% kills the launch gate
Conversion
Incredible17.5%search→purchase rate — share of searches ending in a sale
Review moat
Okay1,793.25avg incumbent reviews — the moat a new listing must climb
Quality gap
Okay4.6★avg incumbent rating — lower means beatable quality
Avg price
Bad£4.03avg listing price — sweet spot $15–$100
Market size
Bad£39K£39K/yr · 55K searches
Growth
Bad-49.0%90-day search growth — must beat 0% to launch
Competition
Bad100%top-5 click share — a locked-up shelf
Brand share
Bad100%top-5 brand share — brand-locked demand
Price range
Bad£2.63–£7.03cheapest to priciest tracked listing — scored on the share inside $15–$100
According to Flapen's Amazon United Kingdom niche tracking, vitamin d 400iu is a £39K/yr Amazon United Kingdom market (55K searches/yr). The top 5 brands hold 100% of demand. Demand peaks in Jan–Feb–Oct–Nov. Verdict: Skip it — 27/100.
Data updated Jul 25, 2026 · scored weekly · How we score niches
vitamin d 400iu market data
- Units sold / yr
- 10K–13K
- avg 1,500–2,000/product
- Revenue / yr
- £40K–£50K
- units × avg price
- Conversion rate
- 17.5%
- Avg BSR
- #41
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 100%
- Out of stock
- 0.0%
- Avg brand age
- 79 months
- Avg seller age
- 174 days
Competition & brand share
The top 5 products capture 100% of clicks — a locked-up shelf that new listings rarely crack.Brands
4 falling
Sellers
16
Top-5 brand share
100%
Top 20: 100%
Top-5 click share
100%
Top 20: 100%
Open market
0%
- Vitabiotics Ultra53%
- Fultium23%
- Natures Aid19%
- PROHEALTH4%
- Open — no brand owns it (0%)
Demand & seasonality
Weekly Amazon search volume, last 86 weeks — -49.0% search growth over the last 90 days.Peak months: Jan, Feb, Oct, Nov · busiest ÷ quietest = 2.8×
Top vitamin d 400iu search terms
- vitamin d 400iu19K/yr
- vitamin d3 400iu8K/yr
- vitamin d 400 iu7K/yr
- vitamin d 10 micrograms10K/yr
- vitamin d 10mcg5K/yr
- vitamin d 10mg4K/yr
- vitamin d 4003K/yr
Top vitamin d 400iu 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.
All 4 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Vitamin D Tablets 400IU Vitabiotics Ultra
Vitabiotics Ultra£2.634.7★1,658 rev
Fultium Vitamin D3 400 IU 10g |90 Tablets|Recommended Daily Dose Vitamin D Supplement | Immune Bone & Muscle Support | from The UKs No.1 Vitamin D Prescription Brand | Vegetarian | Food Supplement
Fultium£2.804.6★58 rev
Natures Aid Vitamin D3 10g (400IU) High Strength Vitamin D Supplement Supports Bones Muscles & Immunity Vegan Gluten-Free Non-GMO 90 Tablets Essential Daily Nutrient
Natures Aid£3.654.6★5,083 rev
Certified Vegan 400IU Vitamin D3 120 Days Tablets for Pregnancy Nursing and Seniors - NHS Approved
PROHEALTH£7.034.5★374 rev
Newest
by launch dateFultium Vitamin D3 400 IU 10g |90 Tablets|Recommended Daily Dose Vitamin D Supplement | Immune Bone & Muscle Support | from The UKs No.1 Vitamin D Prescription Brand | Vegetarian | Food Supplement
Fultium£2.8058 rev
Vitamin D Tablets 400IU Vitabiotics Ultra
Vitabiotics Ultra£2.631,658 rev
Certified Vegan 400IU Vitamin D3 120 Days Tablets for Pregnancy Nursing and Seniors - NHS Approved
PROHEALTH£7.03374 rev
Natures Aid Vitamin D3 10g (400IU) High Strength Vitamin D Supplement Supports Bones Muscles & Immunity Vegan Gluten-Free Non-GMO 90 Tablets Essential Daily Nutrient
Natures Aid£3.655,083 rev
Trending
90-day click momentumFultium Vitamin D3 400 IU 10g |90 Tablets|Recommended Daily Dose Vitamin D Supplement | Immune Bone & Muscle Support | from The UKs No.1 Vitamin D Prescription Brand | Vegetarian | Food Supplement
Fultium£2.804.6★
Vitamin D Tablets 400IU Vitabiotics Ultra
Vitabiotics Ultra£2.634.7★
Natures Aid Vitamin D3 10g (400IU) High Strength Vitamin D Supplement Supports Bones Muscles & Immunity Vegan Gluten-Free Non-GMO 90 Tablets Essential Daily Nutrient
Natures Aid£3.654.6★
Certified Vegan 400IU Vitamin D3 120 Days Tablets for Pregnancy Nursing and Seniors - NHS Approved
PROHEALTH£7.034.5★
What buyers say about vitamin d 400iu
What buyers praise and complain about, mined from review topics.What buyers love
“Good Value”
“Overall, this seems like a good basic vitamin D supplement”
“ideal to swallow”
“Quality feels reliable and consistent, and the bottle has lasted well with regular use”
“Does the job”
“Easy to take”
“piece of mind that I'm not over doing it on dosage, so highly recommend”
“Definitely works”
“I was pleasantly surprised by the size”
“no weird taste or smell”
What buyers complain about
“The capsules are small”
“Slightly bigger tablets than I expected for this dose”
“Don't get nearly enough vit D via the sun”
“96 doesn't work”
“I find tablets are always harder to swallow than capsules”
“Never again - this ingredient should be banned”
“cheap”
“Maltodextrin side effects - just awful”
“A record-breaking waste of container space”
“bad design”
Common questions
- Is vitamin d 400iu profitable to sell on Amazon United Kingdom?
- The niche generates £39K/yr across 4 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is -49.0%. Flapen's verdict: Skip it (27/100).
- How competitive is the vitamin d 400iu niche?
- 4 brands and 16 sellers compete. The top 5 products take 100% of clicks and top 5 brands hold 100% of demand.
- What do buyers complain about in vitamin d 400iu?
- Top complaints mined from reviews: Size-Overall, Dosage, Vitamin. The return rate is 0.0%.
- When does demand for vitamin d 400iu peak?
- Demand peaks in Jan–Feb–Oct–Nov; the busiest month runs 2.8× the quietest.
- What does it cost to enter the vitamin d 400iu niche?
- Listings span £2.63–£7.03; the average listing price is £4.03 (sweet spot $15–$100). The average incumbent carries 1,793 reviews — the moat a new listing must climb.