---
title: "Magnesium 300mg — $6K/mo Amazon US Product Research (2026)"
canonical_url: "https://flapen.com/research/us/health-household/magnesium-300mg"
last_updated: "2026-08-12T14:12:44.172Z"
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description: "Amazon product research for magnesium 300mg: $6K/mo market, demand, competition, pricing, reviews & the verdict. Know if it's worth selling — Flapen."
"og:description": "Amazon product research for magnesium 300mg: $6K/mo market, demand, competition, pricing, reviews & the verdict. Know if it's worth selling — Flapen."
"og:title": "Magnesium 300mg — $6K/mo Amazon US Product Research (2026)"
---
# **Magnesium 300mg**
**Skip it**
A deep review moat (20,452 avg reviews) — this niche doesn't clear our bar today.
Market size 17Growth 18Conversion 86Competition 38Returns 100Price range 73Avg price 86Brand share 34Review moat 16Quality gap 21
**Returns**
**Incredible****0.0%**
return rate — above 5% kills the launch gate
**Conversion**
**Great****9.9%**
search→purchase rate — share of searches ending in a sale
**Avg price**
**Great****$19.52**
avg listing price — sweet spot $15–$100
**Price range**
**Good****$4.10–$45.01**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Competition**
**Okay****62%**
top-5 click share — leaders hold, buyers still browse
**Brand share**
**Okay****85%**
top-5 brand share — brands hold most of the demand
**Quality gap**
**Bad****4.7★**
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**
**Bad****20,452.28**
avg 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 ~~](https://flapen.com/research/methodology)
## **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.
13K8KSpike '24Spike '25Spike '26 seasonSepDecMarJunAugNovMarMay
Peak months: Jan, Feb, Mar · busiest ÷ quietest = 4.2×
[**Open Trend **](https://flapen.com/research/us/health-household/magnesium-300mg/trend)
## **Top magnesium 300mg search terms shoppers use**
The exact queries shoppers type, with yearly volume, growth and conversion.
- **magnesium 300mg**19K/yr-15.7%9.5% conv. - **magnesium 300 mg**5K/yr+11.2%10.0% conv. - **magnesium 300mg for women**4K/yr-7.3%7.0% conv. - **magnesium 300**4K/yr-19.2%10.5% conv. - **300 mg magnesium**3K/yr-28.4%7.4% conv. [**All search terms **](https://flapen.com/research/us/health-household/magnesium-300mg/search-terms)
## **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.
0%10%$7K20%$13K30%$20K40%$26K101001K10K100K1.0M Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 18 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**Nature Made Magnesium Glycinate 300 mg per 3 Capsules 90 Capsules**Nature Made**$21.13**4.7★2,683 rev](https://www.amazon.com/dp/B0D9MV3YJQ) [2**tnvitamins Magnesium Glycinate 300mg 90 Capsules | High Absorption Chelated Magnesium for Sleep Calm & Muscle Support* | Non-GMO Gentle Non-Laxative | TNVitamins**tnvitamins**$9.82**4.7★3,749 rev](https://www.amazon.com/dp/B0B4PRL1SK) [3**Nature Made Magnesium 250 mg Softgels 90 Softgels**Nature Made**$6.57**4.7★34,776 rev](https://www.amazon.com/dp/B008PQD65M) [4**MegaFood Magnesium Glycinate Malate Citrate 300mg 60 Capsules**MegaFood**$15.71**4.6★4,256 rev](https://www.amazon.com/dp/B081FXFHLJ) [5**Pure Encapsulations Magnesium (Glycinate) - Supplement to Support Stress Relief Sleep Heart Health Nerves Muscles and Metabolism* - with Magnesium Glycinate - 90 Capsules**Pure Encapsulations**$26.10**4.7★49,969 rev](https://www.amazon.com/dp/B07P5K7DQP)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**Built By Nature Magnesium Citrate 300mg Supplement 90 Capsules**Built by Nature**$10.52**48 rev10mo ago](https://www.amazon.com/dp/B0FPGPV5D2) [**THORNE - Magnesium Glycinate - Supports Restful Sleep Muscle Relaxation Heart Health & Metabolism* - Chelated Magnesium Capsules - Third-Party Certified - Gluten Dairy & Soy-Free - 90 Servings**THORNE**$25.39**2,847 rev1y ago](https://www.amazon.com/dp/B0F5XYHRPV) [**Qunol Magnesium Glycinate Tablets 300mg 100% Chelated Gluten-Free 150ct**Qunol**$28.24**6,509 rev1y ago](https://www.amazon.com/dp/B0DNV31VXS) [**Nature Made Magnesium Glycinate 300 mg per 3 Capsules 90 Capsules**Nature Made**$21.13**2,683 rev1y ago](https://www.amazon.com/dp/B0D9MV3YJQ) [**Nutricost Triple Magnesium Complex 300mg 120 Capsules 60 Servings**Nutricost**$19.49**314 rev1y ago](https://www.amazon.com/dp/B0DJ1NFCS3)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**Built By Nature Magnesium Citrate 300mg Supplement 90 Capsules**Built by Nature**$10.52**4.6★**▲ 107%**](https://www.amazon.com/dp/B0FPGPV5D2) [**Qunol Magnesium Glycinate Tablets 300mg 100% Chelated Gluten-Free 150ct**Qunol**$28.24**4.6★**▲ 107%**](https://www.amazon.com/dp/B0DNV31VXS) [**Nature Made Magnesium Oxide 250 mg for Muscle Relaxation 200 Tablets**Nature Made**$6.80**4.7★**▲ 84%**](https://www.amazon.com/dp/B0002VG3QC) [**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**$8.74**4.7★**▲ 51%**](https://www.amazon.com/dp/B00H5PJ0HW) [**Nature Made Magnesium Glycinate 300 mg per 3 Capsules 90 Capsules**Nature Made**$21.13**4.7★**▲ 24%**](https://www.amazon.com/dp/B0D9MV3YJQ)
**~~View all trending →~~**
## **What reviews say buyers love and hate about magnesium 300mg**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Quality-Overall**20%
*“Amazing quality”*
**Sleep Quality**20%
*“Great night sleep”*
**Magnesium**14%
*“Best magnesium supplement”*
**Value For Money**5%
*“Great deal”*
**Vitamin**5%
*“Quality vitamins”*
**Advertised Vs Actual Product**4%
*“exactly as advertised”*
**Muscle Pain Relief**3%
*“muscle recovery”*
**Efficiency**2%
*“it gets the job done”*
**Stress/Anxiety**2%
*“less stress”*
**Ease Of Chewing/Swallowing**2%
*“Easier to swallow”*
### **What buyers complain about **
**Sleep Quality**12%
*“I was having trouble sleeping”*
**Magnesium**10%
*“Know magnesium is low”*
**Size-Overall**8%
*“Too Big”*
**Dosage**6%
*“Misleading dosage”*
**Acid Regulator/Stomach Ache Relief**5%
*“Hard on my stomach”*
**Side Effects**5%
*“This was really upsetting my stomach even right after I ate something”*
**Functionality-Overall**4%
*“noticed no results”*
**Ease Of Chewing/Swallowing**4%
*“VERY DIFFICULT TO SWALLOW”*
**Quality-Overall**4%
*“Poor quality control”*
**Value For Money**3%
*“Waste of money”*
### **Top return reasons **
**Magnesium**31%
**Dosage**11%
**Functionality-Overall**9%
**Acid Regulator/Stomach Ache Relief**7%
**Value For Money**6%
**Sleep Quality**5%
**Size-Overall**5%
**Ease Of Chewing/Swallowing**4%
**Advertised Vs Actual Product**3%
**Vitamin**3%
## **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.
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