Is l theanine profitable to sell on Amazon United Kingdom?

The niche generates £742K/yr across 15 tracked products. 2 of 4 products launched in the last 360 days are still selling. 90-day search growth is +1.8%. Flapen's verdict: Worth a look (53/100).

How competitive is the l theanine niche?

14 brands and 18 sellers compete. The top 5 products take 73% of clicks and top 5 brands hold 73% of demand.

What do buyers complain about in l theanine?

Top complaints mined from reviews: Dosage, Sleep Quality, Smell. The return rate is 0.0%.

When does demand for l theanine peak?

Demand peaks in Apr–May; the busiest month runs 2.0× the quietest.

What does it cost to enter the l theanine niche?

Listings span £4.98–£17.18; the average listing price is £8.63 (sweet spot $15–$100). The average incumbent carries 1,516 reviews — the moat a new listing must climb.

l theanine

Worth a look

Shows low returns (0.0%), but prices mostly outside the sweet spot ($4.98–$17.18) keeps it on the watch list.

Returns

Incredible0.0%

return rate — above 5% kills the launch gate

Conversion

Incredible14.8%

search→purchase rate — share of searches ending in a sale

Market size

Good£742K

£742K/yr · 580K searches

Quality gap

Good4.4★

avg incumbent rating — lower means beatable quality

Brand share

Good73%

top-5 brand share — brands hold most of the demand

Review moat

Okay1,515.67

avg incumbent reviews — the moat a new listing must climb

Growth

Okay+1.8%

90-day search growth — must beat 0% to launch

Avg price

Bad£8.63

avg listing price — sweet spot $15–$100

Competition

Bad73%

top-5 click share — a locked-up shelf

Price range

Bad£4.98–£17.18

cheapest to priciest tracked listing — scored on the share inside $15–$100

Signals Low Review Barrier

According to Flapen's Amazon United Kingdom niche tracking, l theanine is a £742K/yr Amazon United Kingdom market (580K searches/yr). The top 5 brands hold 73% of demand. Demand peaks in Apr–May. Verdict: Worth a look — 53/100.

Data updated Jul 25, 2026 · scored weekly · How we score niches

l theanine market data

Units sold / yr: 60K–80K; avg 5,000–6,000/product
Revenue / yr: £518K–£690K; units × avg price
Conversion rate: 14.8%
Avg BSR: #120
Page quality: 0%
Prime: 100%
Sponsored: 93%
Out of stock: 10.3%
Avg brand age: 36 months
Avg seller age: 168 days

Competition & brand share

The top 5 products capture 73% of clicks — a locked-up shelf that new listings rarely crack.

Brands

14 falling

Sellers

Top-5 brand share

73%

Top 20: 100%

Top-5 click share

73%

Top 20: 100%

Open market

18%

NUTRINATION22%
NEW LEAF PRODUCTS21%
Nutrivo12%
Nutricost10%
SS Sport Supplies9%
WeightWorld8%

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — +1.8% search growth over the last 90 days.

Peak months: Apr, May · busiest ÷ quietest = 2.0×

Open Trend

Top l theanine search terms

l theanine265K/yr +10.7%12.5% conv.
l-theanine169K/yr -6.2%12.0% conv.
l theanine 400mg22K/yr +108.3%17.0% conv.
ltheanine25K/yr +17.8%12.4% conv.
theanine26K/yr -3.4%11.5% conv.
l-theanine 400mg10K/yr +9.6%15.4% conv.
suntheanine7K/yr +4.9%2.4% conv.
l theanine supplement34K/yr -80.2%9.6% conv.
l theanine 100mg5K/yr -2.1%3.0% conv.
l- theanine5K/yr -15.9%7.2% conv.

All search terms

Top l theanine 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.

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

L Theanine 400mg Capsules - 99.6% Pure L-Theanine | 5 Months Supply - 150 Capsules | Supports Relaxation & Focus Promotes Calm | Zero Additives Vegan & Non-GMO | GMP - Certified Lab Tested

NUTRINATION£9.484.6★171 rev

L Theanine Enriched with Vitamin B6 - High Strength L-Theanine Capsules 400mg Natural Nootropics from Green Tea - 120 Vegan Capsules - Made in The UK Supplements by New Leaf

NEW LEAF PRODUCTS£7.994.5★729 rev

L Theanine 400mg | 120 Vegan Capsules - 4 Months Supply | Good Alternative to L-Theanine Powder Gummies and Drops | UK Made LTheanine Supplement

Nutrivo£7.734.6★473 rev

Nutricost L-Theanine 200mg 120 Capsules - Non-GMO Gluten Free

Nutricost£6.664.4★9,555 rev

L-Theanine Green Tea Extract with Added Lemon Balm Extract and Chelated Magnesium Glycinate - Derived from Green Tea Leaves - Sleep & Relaxation Support - Mental Clarity

SS Sport Supplies£5.534.0★46 rev

Newest

by launch date

L-Theanine Green Tea Extract with Added Lemon Balm Extract and Chelated Magnesium Glycinate - Derived from Green Tea Leaves - Sleep & Relaxation Support - Mental Clarity

SS Sport Supplies£5.5346 rev

6mo ago

L Theanine Gummies - 200 mg L-Theanine Supplement with Lemon Balm & Vitamin B6 - Supports Nervous System & Hormonal Function - Vegan Halal - 60 Count - Novomins

novomins£11.4735 rev

6mo ago

Natures Best L Theanine 200mg 60 Capsules (2 Month Supply)

NATURE'S BEST£10.7149 rev

9mo ago

NutriVolv£5.7359 rev

10mo ago

L Theanine 400mg Capsules - 99.6% Pure L-Theanine | 5 Months Supply - 150 Capsules | Supports Relaxation & Focus Promotes Calm | Zero Additives Vegan & Non-GMO | GMP - Certified Lab Tested

NUTRINATION£9.48171 rev

1y ago

What buyers say about l theanine

What buyers praise and complain about, mined from review topics.

What buyers love

Sleep Quality15%

“Helpful for sleep”

Quality-Overall11%

“appears to be well made”

Stress/Anxiety9%

“Great for anxiety”

Value For Money9%

“Good value for money”

Focus Enhancement5%

“less brain fog”

Ease Of Chewing/Swallowing4%

“I found the chewy”

Vitamin4%

“Good supplement”

Soothing Effect4%

“Very calming”

Ease Of Use3%

“Ease of use”

Advertised Vs Actual Product3%

“As advertised”

What buyers complain about

Dosage9%

“Not enough to be clinically effective at all”

Sleep Quality8%

“Didn't help with Sleep”

Smell8%

“Smelled absolutely awful”

Ingredients-Overall6%

“Ingredients have changed”

Side Effects5%

“After taking these for a few day I was experiencing really bad pain in my abdomen”

Functionality-Overall5%

“Dont work”

Advertised Vs Actual Product5%

“misleading”

Stress/Anxiety5%

“Stress and anexity”

Quality-Overall3%

“Just wish the quality control was a bit better”

Vitamin2%

“Think the vit B6 levels is low for a supplement”

Top return reasons

Certifications100%

Common questions

Is l theanine profitable to sell on Amazon United Kingdom?: The niche generates £742K/yr across 15 tracked products. 2 of 4 products launched in the last 360 days are still selling. 90-day search growth is +1.8%. Flapen's verdict: Worth a look (53/100).
How competitive is the l theanine niche?: 14 brands and 18 sellers compete. The top 5 products take 73% of clicks and top 5 brands hold 73% of demand.
What do buyers complain about in l theanine?: Top complaints mined from reviews: Dosage, Sleep Quality, Smell. The return rate is 0.0%.
When does demand for l theanine peak?: Demand peaks in Apr–May; the busiest month runs 2.0× the quietest.
What does it cost to enter the l theanine niche?: Listings span £4.98–£17.18; the average listing price is £8.63 (sweet spot $15–$100). The average incumbent carries 1,516 reviews — the moat a new listing must climb.