Is tryptophan profitable to sell on Amazon United Kingdom?

The niche generates £37K/yr across 10 tracked products. 0 of 3 products launched in the last 360 days are still selling. 90-day search growth is -12.7%. Flapen's verdict: Skip it (42/100).

How competitive is the tryptophan niche?

10 brands and 11 sellers compete. The top 5 products take 81% of clicks and top 5 brands hold 81% of demand.

What do buyers complain about in tryptophan?

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

When does demand for tryptophan peak?

Demand peaks in Oct; the busiest month runs 1.5× the quietest.

What does it cost to enter the tryptophan niche?

Listings span £6.59–£16.21; the average listing price is £9.52 (sweet spot $15–$100). The average incumbent carries 773 reviews — the moat a new listing must climb.

tryptophan

Skip it

A small market ($37K/yr) — this niche doesn't clear our bar today.

Returns

Incredible0.0%

return rate — above 5% kills the launch gate

Conversion

Great8.6%

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

Quality gap

Great4.3★

avg incumbent rating — lower means beatable quality

Review moat

Good772.7

avg incumbent reviews — the moat a new listing must climb

Brand share

Okay81%

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

Avg price

Okay£9.52

avg listing price — sweet spot $15–$100

Growth

Bad-12.7%

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

Competition

Bad81%

top-5 click share — a locked-up shelf

Price range

Bad£6.59–£16.21

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

Market size

Bad£37K

£37K/yr · 45K searches

Signals Low Review Barrier

According to Flapen's Amazon United Kingdom niche tracking, tryptophan is a £37K/yr Amazon United Kingdom market (45K searches/yr). The top 5 brands hold 81% of demand. Demand peaks in Oct. Verdict: Skip it — 42/100.

Data updated Jul 24, 2026 · scored weekly · How we score niches

tryptophan market data

Units sold / yr: 4K–5K; avg 250–500/product
Revenue / yr: £38K–£48K; units × avg price
Conversion rate: 8.6%
Avg BSR: #683
Page quality: 0%
Prime: 100%
Sponsored: 80%
Out of stock: 3.1%
Avg brand age: 43 months
Avg seller age: 184 days

Competition & brand share

The top 5 products capture 81% of clicks — a locked-up shelf that new listings rarely crack.

Brands

10 falling

Sellers

Top-5 brand share

81%

Top 20: 100%

Top-5 click share

81%

Top 20: 100%

Open market

15%

ALPHA0134%
Vegavero24%
Horbäach11%
Nutrition Geeks7%
Nutriodol5%
swiss bioenergetics4%
Open — no brand owns it (4 brands, 15%)

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — -12.7% search growth over the last 90 days.

Peak months: Oct · busiest ÷ quietest = 1.5×

Open Trend

Top tryptophan search terms

tryptophan19K/yr -10.2%8.0% conv.
l tryptophan12K/yr +4.7%7.8% conv.
l-tryptophan10K/yr -30.3%8.5% conv.
tryptophan supplement4K/yr -23.5%11.1% conv.

All search terms

Top tryptophan 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 10 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

L-Tryptophan 220mg with BioPerine - 90 Vegan Capsules Naturally Fermented L-Tryptophan Supplement with Black Pepper Extract for Increased Bioavailability - 3 Months Supply - By Alpha01

ALPHA01£6.594.5★114 rev

Vegavero£13.734.4★142 rev

L-Tryptophan 220mg | 120 Vegan Tablets | High Strength Amino Acid | Suitable for Vegetarians and Vegans | by Horbaach

Horbäach£7.174.0★170 rev

Ashwagandha KSM 66 Complex 3000mg Enhanced with L-Tryptophan & Vitamin B6 (2 Month Supply) Ashwagandha High Strength Capsules with 250mg Extract (Not Gummies or Powder) - Vegan UK Made

Nutrition Geeks£7.264.4★6,943 rev

Nutriodol£7.084.6★14 rev

Newest

by launch date

Ashwagandha High Strength KSM-66 Valerian Root & L-Tryptophan Supplement with Magnesium Zinc & Vitamin B6 UK Made 2 Month Supply 60 Vegan Capsules

STRENGTH & SPICES100% Natural Vegan Food Supplements£8.3330 rev

6mo ago

NaturaVive+ L-Tryptophan Complex 120 Capsules | One a Day | with Vitamin B6 Niacin and Magnesium | Food Supplement

NaturaVive£16.2114 rev

10mo ago

Nutriodol£7.0814 rev

10mo ago

L-Tryptophan Sleep Complex with Lemon Balm & Chamomile Enhanced with Magnesium Niacin & Vitamin B6 - Natural Night Complex Alternative to Melatonin - 120 Capsules (4-Month Supply) - Made in the UK

Xspan Labs£8.2472 rev

2y ago

Vegavero£13.73142 rev

2y ago

What buyers say about tryptophan

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

What buyers love

Sleep Quality20%

“Helped me sleep”

Quality-Overall14%

“Excellent product”

Stress/Anxiety8%

“calming daily stressors”

Value For Money7%

“Not to expensive”

Ease Of Chewing/Swallowing6%

“Good value, easily swallowed supplement”

Vitamin5%

“Good supplement”

Ease Of Use5%

“Ease of use”

Soothing Effect3%

“They help me relax”

Efficiency3%

“Seem effective”

Ingredients-Overall2%

“Great mixture of ingredients”

What buyers complain about

Dosage13%

“Not enough to be clinically effective at all”

Ingredients-Overall12%

“Ingredients have changed”

Sleep Quality10%

“Disrupted sleep”

Side Effects8%

“I've found a strange side effect at the outset of taking a capsule, a weird”

Advertised Vs Actual Product7%

“misleading”

Acid Regulator/Stomach Ache Relief4%

“However I started noticing lots of bloating, stomach issues and acne”

Functionality-Overall3%

“Didnt work for me”

Quality-Overall3%

“Just wish the quality control was a bit better”

Size-Overall3%

“Just a small thing”

Vitamin3%

“And explains why so many supplements do absolutely nothing”

Top return reasons

Certifications100%

Common questions

Is tryptophan profitable to sell on Amazon United Kingdom?: The niche generates £37K/yr across 10 tracked products. 0 of 3 products launched in the last 360 days are still selling. 90-day search growth is -12.7%. Flapen's verdict: Skip it (42/100).
How competitive is the tryptophan niche?: 10 brands and 11 sellers compete. The top 5 products take 81% of clicks and top 5 brands hold 81% of demand.
What do buyers complain about in tryptophan?: Top complaints mined from reviews: Dosage, Ingredients-Overall, Sleep Quality. The return rate is 0.0%.
When does demand for tryptophan peak?: Demand peaks in Oct; the busiest month runs 1.5× the quietest.
What does it cost to enter the tryptophan niche?: Listings span £6.59–£16.21; the average listing price is £9.52 (sweet spot $15–$100). The average incumbent carries 773 reviews — the moat a new listing must climb.