Magnesium 300mg
Skip itA deep review moat (20,452 avg reviews) — this niche doesn't clear our bar today.
Returns
Incredible0.0%return rate — above 5% kills the launch gate
Conversion
Great9.9%search→purchase rate — share of searches ending in a sale
Avg price
Great$19.52avg listing price — sweet spot $15–$100
Price range
Good$4.10–$45.01cheapest to priciest tracked listing — scored on the share inside $15–$100
Competition
Okay62%top-5 click share — leaders hold, buyers still browse
Brand share
Okay85%top-5 brand share — brands hold most of the demand
Quality gap
Bad4.7★avg incumbent rating — lower means beatable quality
Growth
Bad-13.1%90-day search growth — must beat 0% to launch
Market size
Bad$66K$66K/yr · 34K searches
Review moat
Bad20,452.28avg incumbent reviews — the moat a new listing must climb
Is magnesium 300mg profitable on Amazon?
According to Flapen's Amazon United States niche tracking, magnesium 300mg is a $66K/yr Amazon United States market (34K searches/yr). The top 5 brands hold 85% of demand. Demand peaks in Jan–Feb–Mar. Verdict: Skip it — 44/100.
Data updated Jul 28, 2026 · scored weekly · How we score niches
magnesium 300mg market size & sales
Units sold, revenue, conversion and listing quality across the tracked shelf.- Units sold / yr
- 3K–4K
- avg 100–250/product
- Revenue / yr
- $59K–$78K
- units × avg price
- Conversion rate
- 9.9%
- Avg BSR
- #220
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 83%
- Out of stock
- 0.0%
- Avg brand age
- 73 months
- Avg seller age
- 150 days
Competition: brands, sellers & click share
The top 5 products take 62% of clicks — established leaders, but buyers still shop beyond them.Brands
12 rising
Sellers
621
Top-5 brand share
85%
Top 20: 100%
Top-5 click share
62%
Top 20: 100%
Open market
10%
- Nature Made45%
- tnvitamins13%
- MegaFood11%
- Qunol8%
- Pure Encapsulations8%
- BioEmblem5%
- Open — no brand owns it (6 brands, 10%)
magnesium 300mg demand & seasonality
Weekly Amazon search volume, last 102 weeks — -13.1% search growth over the last 90 days.Peak months: Jan, Feb, Mar · busiest ÷ quietest = 4.2×
Top magnesium 300mg search terms shoppers use
The exact queries shoppers type, with yearly volume, growth and conversion.- magnesium 300mg19K/yr
- magnesium 300 mg5K/yr
- magnesium 300mg for women4K/yr
- magnesium 3004K/yr
- 300 mg magnesium3K/yr
Top magnesium 300mg products & what they sell for
Every tracked product — its share of the shelf, its review moat, and what it sells for.Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.
All 18 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
Nature Made Magnesium Glycinate 300 mg per 3 Capsules 90 Capsules
Nature Made$21.134.7★2,683 rev
tnvitamins Magnesium Glycinate 300mg 90 Capsules | High Absorption Chelated Magnesium for Sleep Calm & Muscle Support* | Non-GMO Gentle Non-Laxative | TNVitamins
tnvitamins$9.824.7★3,749 rev
Nature Made Magnesium 250 mg Softgels 90 Softgels
Nature Made$6.574.7★34,776 rev
MegaFood Magnesium Glycinate Malate Citrate 300mg 60 Capsules
MegaFood$15.714.6★4,256 rev
Pure Encapsulations Magnesium (Glycinate) - Supplement to Support Stress Relief Sleep Heart Health Nerves Muscles and Metabolism* - with Magnesium Glycinate - 90 Capsules
Pure Encapsulations$26.104.7★49,969 rev
Newest
by launch date
Built By Nature Magnesium Citrate 300mg Supplement 90 Capsules
Built by Nature$10.5248 rev
THORNE - Magnesium Glycinate - Supports Restful Sleep Muscle Relaxation Heart Health & Metabolism* - Chelated Magnesium Capsules - Third-Party Certified - Gluten Dairy & Soy-Free - 90 Servings
THORNE$25.392,847 rev
Qunol Magnesium Glycinate Tablets 300mg 100% Chelated Gluten-Free 150ct
Qunol$28.246,509 rev
Nature Made Magnesium Glycinate 300 mg per 3 Capsules 90 Capsules
Nature Made$21.132,683 rev
Nutricost Triple Magnesium Complex 300mg 120 Capsules 60 Servings
Nutricost$19.49314 rev
Trending
90-day click momentumBuilt By Nature Magnesium Citrate 300mg Supplement 90 Capsules
Built by Nature$10.524.6★
Qunol Magnesium Glycinate Tablets 300mg 100% Chelated Gluten-Free 150ct
Qunol$28.244.6★
Nature Made Magnesium Oxide 250 mg for Muscle Relaxation 200 Tablets
Nature Made$6.804.7★
Natures Bounty Magnesium 500 mg Tablets High Potency Magnesium Supplement for Bone & Muscle Health Whole Body Support 200 Count (Pack of 1)
Nature's Bounty$8.744.7★
Nature Made Magnesium Glycinate 300 mg per 3 Capsules 90 Capsules
Nature Made$21.134.7★
What reviews say buyers love and hate about magnesium 300mg
What buyers praise and complain about, mined from review topics.What buyers love
“Amazing quality”
“Great night sleep”
“Best magnesium supplement”
“Great deal”
“Quality vitamins”
“exactly as advertised”
“muscle recovery”
“it gets the job done”
“less stress”
“Easier to swallow”
What buyers complain about
“I was having trouble sleeping”
“Know magnesium is low”
“Too Big”
“Misleading dosage”
“Hard on my stomach”
“This was really upsetting my stomach even right after I ate something”
“noticed no results”
“VERY DIFFICULT TO SWALLOW”
“Poor quality control”
“Waste of money”
Top return reasons
Common magnesium 300mg questions
- Is magnesium 300mg profitable to sell on Amazon United States?
- The niche generates $66K/yr across 18 tracked products. 0 of 1 products launched in the last 360 days are still selling. 90-day search growth is -13.1%. Flapen's verdict: Skip it (44/100).
- How competitive is the magnesium 300mg niche?
- 12 brands and 621 sellers compete. The top 5 products take 62% of clicks and top 5 brands hold 85% of demand.
- What do buyers complain about in magnesium 300mg?
- Top complaints mined from reviews: Sleep Quality, Magnesium, Size-Overall. The return rate is 0.0%.
- When does demand for magnesium 300mg peak?
- Demand peaks in Jan–Feb–Mar; the busiest month runs 4.2× the quietest.
- What does it cost to enter the magnesium 300mg niche?
- Listings span $4.10–$45.01; the average listing price is $19.52 (sweet spot $15–$100). The average incumbent carries 20,452 reviews — the moat a new listing must climb.