---
title: "Fos — $81K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/health-household/fos"
last_updated: "2026-08-11T20:43:55.043Z"
locale: en
meta:
description: "Niche score 43/100 · $81K/yr market · 126K searches/yr · $18.51 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:description": "Niche score 43/100 · $81K/yr market · 126K searches/yr · $18.51 avg price. Doesn't clear our bar today. Data updated Jul 2026."
"og:title": "Fos — $81K/yr Amazon US Niche (2026) - Flapen"
---
# **fos**
**Skip it**
Soft demand (-15.8% this quarter) — this niche doesn't clear our bar today.
Market size 20Growth 17Conversion 44Competition 25Returns 100Price range 73Avg price 84Brand share 35Review moat 63Quality gap 47
**Returns**
**Incredible****0.0%**
return rate — above 5% kills the launch gate
**Avg price**
**Great****$18.51**
avg listing price — sweet spot $15–$100
**Price range**
**Good****$8.78–$31.56**
cheapest to priciest tracked listing — scored on the share inside $15–$100
**Review moat**
**Good****968.4**
avg incumbent reviews — the moat a new listing must climb
**Quality gap**
**Okay****4.5★**
avg incumbent rating — lower means beatable quality
**Conversion**
**Okay****3.5%**
search→purchase rate — share of searches ending in a sale
**Brand share**
**Okay****84%**
top-5 brand share — brands hold most of the demand
**Competition**
**Okay****70%**
top-5 click share — leaders hold, buyers still browse
**Market size**
**Bad****$81K**
$81K/yr · 126K searches
**Growth**
**Bad****-15.8%**
90-day search growth — must beat 0% to launch
**Signals**[** Low Review Barrier**](https://flapen.com/research/niches?market=us&signal=low_review_barrier "Top brand's reviews < 500")
According to Flapen's Amazon United States niche tracking, fos is a $81K/yr Amazon United States market (126K searches/yr). The top 5 brands hold 84% of demand. Demand peaks in Aug–Dec. Verdict: Skip it — 43/100.
Data updated Jul 25, 2026 · scored weekly · [~~How we score niches ~~](https://flapen.com/research/methodology)
## **fos market data**
- **Units sold / yr**
- **4K–5K**
- avg 250–500/product
- **Revenue / yr**
- **$74K–$93K**
- units × avg price
- **Conversion rate**
- **3.5%**
- **Avg BSR**
- **#898**
- **Page quality**
- **0%**
- **Prime**
- **100%**
- **Sponsored**
- **73%**
- **Out of stock**
- **0.9%**
- **Avg brand age**
- **72 months**
- **Avg seller age**
- **153 days**
## **Competition & brand share**
The top 5 products take 70% of clicks — established leaders, but buyers still shop beyond them.
**Brands**
**10 **▼falling
**Sellers**
**27**
**Top-5 brand share**
**84%**
Top 20: 100%
**Top-5 click share**
**70%**
Top 20: 100%
**Open market**
**10%**
- NOW Foods22% - PURE ORIGINAL INGREDIENTS18% - Supersmart18% - Micro Ingredients17% - Source Naturals10% - Kidney Restore7% - Open — no brand owns it (4 brands, 10%)
## **Demand & seasonality**
Weekly Amazon search volume, last 98 weeks — -15.8% search growth over the last 90 days.
5K3KSpike '24Holiday '24Spike '25Prime Day '25Black Friday '25Holiday '25Spike '26 seasonDecMarJunAugNovMarMay
Peak months: Aug, Dec · busiest ÷ quietest = 1.8×
[**Open Trend **](https://flapen.com/research/us/health-household/fos/trend)
## **Top fos search terms**
- **fos**91K/yr-2.7%0.9% conv. - **fructooligosaccharides**11K/yr-33.8%6.3% conv. - **fos powder**10K/yr-39.7%10.7% conv. - **fos powder organic**4K/yr-20.8%9.9% conv. - **fos supplement**3K/yr-46.1%7.8% conv. - **fructooligosaccharides powder**3K/yr-51.6%10.2% conv. - **fructooligosaccharide**2K/yr-74.3%3.0% conv. - **fructooligosaccharides prebiotic**2K/yr-84.2%0.0% conv. [**All search terms **](https://flapen.com/research/us/health-household/fos/search-terms)
## **Top fos 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%$8K20%$16K30%$24K40%$32K101001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
Beatable (≤4.3★) Contested Strong incumbent (>4.7★)
All 15 tracked products in this niche — three views at once, no toggling.
### **Top sellers**
by 90-day click share
[1**NOW Foods Supplements NutraFlora FOS (Fructooligosaccharides) Pure Powder Prebiotic Fiber 4-Ounce**NOW Foods**$11.63**4.5★341 rev](https://www.amazon.com/dp/B0002JIXLM) [2**Supersmart Fructo Oligosaccharides Powder (Prebiotics FOS) - Oligofructose Inulin - Fiber Supplement | Non-GMO & Gluten Free - 200 g**Supersmart**$17.17**4.3★93 rev](https://www.amazon.com/dp/B00LPJNOB2) [3**Pure Original Ingredients Fructooligosaccharides 4oz No Additives FOS Powder**PURE ORIGINAL INGREDIENTS**$9.88**4.5★116 rev](https://www.amazon.com/dp/B0B5VV219L) [4**Micro Ingredients Organic Inulin FOS Fiber Powder 2.2 lbs | Quick Water-Soluble Prebiotic | Natural Fiber for Smoothies & Drinks | Vegan Friendly Dissolves Clear**Micro Ingredients**$29.92**4.6★5,239 rev](https://www.amazon.com/dp/B074WKCPS4) [5**Perfect Gut: Inulin FOS Powder for Gut Health. Prebiotic Inulin. Unique Prebiotic 95% FOS Agave Fiber**Kidney Restore**$31.56**4.4★139 rev](https://www.amazon.com/dp/B0DGRFFKWJ)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**Micro Ingredients Organic Inulin FOS Fiber Powder 1.1 lb | Quick Water-Soluble Prebiotic | Natural Unflavored Fiber for Yogurt Smoothies & Drinks | Vegan Friendly Dissolves Clear Non-GMO**Micro Ingredients**$19.72**5,239 rev1y ago](https://www.amazon.com/dp/B0FGFJFFBY) [**Nutricost Prebiotic Fiber Unflavored (1 Pound) Gluten Free**Nutricost**$19.62**251 rev1y ago](https://www.amazon.com/dp/B0F22L62DC) [**Perfect Gut: Inulin FOS Powder for Gut Health. Prebiotic Inulin. Unique Prebiotic 95% FOS Agave Fiber**Kidney Restore**$31.56**139 rev1y ago](https://www.amazon.com/dp/B0DGRFFKWJ) [**Micro Ingredients Vitality Prebiotic Fiber Powder 1lb | Easy Mix Powder for Digestive & Gut Health | Daily Prebiotic Soluble Fiber Supplement for Women and Men | Unflavored Sugar Free & Vegan**Micro Ingredients**$13.26**289 rev1y ago](https://www.amazon.com/dp/B0DK69WWNQ) [**Prebiotic Fiber Supplement 5-in-1 Capsules - Natural Flow 5X Fiber XOS GOS FOS Acacia and Agave Inulin Daily Soluble Fiber Formula for Gut Support and Boost Good Bacteria Diversity 120 Caps**Natural Flow Supplements**$26.20**500 rev3y ago](https://www.amazon.com/dp/B0BM8GP89S)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**Sprout Living Organic Inulin with FOS Prebiotic Powder Soluble Fiber for Leaky Gut Bloating Digestion Feed Friendly Bacteria (Probiotics) 1 Scoop Daily 1 lb (90 Servings)**Sprout Living**$19.76**4.7★**▲ 90%**](https://www.amazon.com/dp/B075S7M8XN) [**Swanson Prebiotic Fiber Capsules with NutraFlora FOS for Gut-Health-Conscious Adults Seeking Digestive Flora and Immune Support - 750 mg (120 Vegan Capsules)**Swanson**$15.86**4.6★**▲ 65%**](https://www.amazon.com/dp/B075NDQP5B) [**Micro Ingredients Organic Inulin FOS Fiber Powder 1.1 lb | Quick Water-Soluble Prebiotic | Natural Unflavored Fiber for Yogurt Smoothies & Drinks | Vegan Friendly Dissolves Clear Non-GMO**Micro Ingredients**$19.72**4.6★**▲ 45%**](https://www.amazon.com/dp/B0FGFJFFBY) [**Nutricost Prebiotic Fiber Unflavored (1 Pound) Gluten Free**Nutricost**$19.62**4.5★**▲ 44%**](https://www.amazon.com/dp/B0F22L62DC) [**Prebiotic Fiber Supplement 5-in-1 Capsules - Natural Flow 5X Fiber XOS GOS FOS Acacia and Agave Inulin Daily Soluble Fiber Formula for Gut Support and Boost Good Bacteria Diversity 120 Caps**Natural Flow Supplements**$26.20**4.5★**▲ 22%**](https://www.amazon.com/dp/B0BM8GP89S)
**~~View all trending →~~**
## **What buyers say about fos**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Quality-Overall**13%
*“Excellent product”*
**Solubility**11%
*“The powder mixes well”*
**Nutritional Content**11%
*“I believe it's a good overall probiotic”*
**Regulates Digestion**9%
*“it completely cleared up my constipation which had been a problem on”*
**Value For Money**7%
*“Good price”*
**Taste-Overall**7%
*“Good taste and healthy”*
**Efficiency**5%
*“Works well”*
**Sweetness**4%
*“It has a mild sweet flavor”*
**Advertised Vs Actual Product**4%
*“As advertised”*
**Flavor**2%
*“enjoy without affecting their flavor”*
### **What buyers complain about **
**Taste-Overall**8%
*“I cant taste in water”*
**Ingredients-Overall**7%
*“not the bag's ingredients list”*
**Solubility**5%
*“I don't like that it dissolves well in water”*
**Side Effects**5%
*“This product gives HORRIBLE GAS”*
**Advertised Vs Actual Product**4%
*“I don't appreciate deceptive product description”*
**Nutritional Content**4%
*“There are not enough carbs or calories for this product to contain whole milk powder”*
**Dosage**4%
*“the amount is too much for me”*
**Acid Regulator/Stomach Ache Relief**3%
*“and my stomach told me that it was way too much”*
**Functionality-Overall**3%
*“Doesnt work”*
**Regulates Digestion**3%
*“I don't recommend it to people with digestive problems”*
### **Top return reasons **
**Functionality-Overall**40%
**Advertised Vs Actual Product**20%
**Artificial Sweeteners**20%
**Acid Regulator/Stomach Ache Relief**20%
## **Common questions**
- **Is fos profitable to sell on Amazon United States?**
- The niche generates $81K/yr across 15 tracked products. 90-day search growth is -15.8%. Flapen's verdict: Skip it (43/100).
- **How competitive is the fos niche?**
- 10 brands and 27 sellers compete. The top 5 products take 70% of clicks and top 5 brands hold 84% of demand.
- **What do buyers complain about in fos?**
- Top complaints mined from reviews: Taste-Overall, Ingredients-Overall, Solubility. The return rate is 0.0%.
- **When does demand for fos peak?**
- Demand peaks in Aug–Dec; the busiest month runs 1.8× the quietest.
- **What does it cost to enter the fos niche?**
- Listings span $8.78–$31.56; the average listing price is $18.51 (sweet spot $15–$100). The average incumbent carries 968 reviews — the moat a new listing must climb.
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