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Cheapest Suntheanine? L-Theanine on iHerb

Ranked by real cost per 10 mg of Suntheanine? L-Theanine — cheapest value first.

Prices updated Jul 25, 2026 · 17 products · Prices in USD

The priciest option here costs about 13.2× more per 10 mg of Suntheanine? L-Theanine than the best-value pick Natural Factors. For the same daily dose, choosing by cost per unit instead of sticker price can meaningfully cut your yearly spend.
#ProductDoseServingsPrice (USD)Cost per 10 mg
1
Natural Factors, Stress-Relax, Suntheanine, L-Theanine, 60 Vegetarian Capsules (125 mg per Capsule)
Natural Factors, Stress-Relax, Suntheanine, L-Theanine, 60 Vegetarian Capsules (125 mg per Capsule)
Natural Factors
250 mg3018.870.025View on iHerb →
2
Natural Factors, Stress-Relax, Suntheanine L-Theanine, 100 mg, 120 Chewable Tablets
Natural Factors, Stress-Relax, Suntheanine L-Theanine, 100 mg, 120 Chewable Tablets
Natural Factors
200 mg6035.670.030View on iHerb →
3
Natural Factors, Stress-Relax, Tranquil Sleep, 45 Enteric Coated Softgels
Natural Factors, Stress-Relax, Tranquil Sleep, 45 Enteric Coated Softgels
Natural Factors
200 mg2213.970.032View on iHerb →
4
NaturesPlus, Pro, Suntheanine L-Theanine 200, 60 Capsules (100 mg per Capsule)
NaturesPlus, Pro, Suntheanine L-Theanine 200, 60 Capsules (100 mg per Capsule)
NaturesPlus
200 mg3019.510.033View on iHerb →
5
Natural Factors, Stress-Relax, Tranquil Sleep, 5-HTP, Suntheanine & Melatonin, 120 Chewable Tablets
Natural Factors, Stress-Relax, Tranquil Sleep, 5-HTP, Suntheanine & Melatonin, 120 Chewable Tablets
Natural Factors
200 mg6041.970.035View on iHerb →
6
Natural Factors, Stress-Relax®, Tranquil Sleep®, 60 Chewable Tablets
Natural Factors, Stress-Relax®, Tranquil Sleep®, 60 Chewable Tablets
Natural Factors
200 mg3022.370.037View on iHerb →
7
Allergy Research Group, Zen, 120 Vegetarian Capsules
Allergy Research Group, Zen, 120 Vegetarian Capsules
Allergy Research Group
200 mg6058.690.049View on iHerb →
8
Dr. Mercola, L-Theanine Plus Gaba, 60 Capsules
Dr. Mercola, L-Theanine Plus Gaba, 60 Capsules
Dr. Mercola
200 mg3032.990.055View on iHerb →
9
Futurebiotics, EstroComfort®, Menopausal Balancing Complex, 56 Vegetarian Capsules
Futurebiotics, EstroComfort®, Menopausal Balancing Complex, 56 Vegetarian Capsules
Futurebiotics
100 mg2816.770.060View on iHerb →
10
Emerald Laboratories, Sleep Health, 60 Vegetable Caps
Emerald Laboratories, Sleep Health, 60 Vegetable Caps
Emerald Laboratories
150 mg3031.460.070View on iHerb →
11
Futurebiotics, Stressassist®, L-Theanine Stress Complex, 60 Vegetarian Capsules
Futurebiotics, Stressassist®, L-Theanine Stress Complex, 60 Vegetarian Capsules
Futurebiotics
100 mg3022.370.075View on iHerb →
12
Vthrive, Magnesium Relax, Raspberry Lemon, 8.5 oz (235 g)
Vthrive, Magnesium Relax, Raspberry Lemon, 8.5 oz (235 g)
Vthrive
50 mg5021.990.088View on iHerb →
13
Nature's Answer, Liquid Tart Cherry, 8 fl oz (240 ml)
Nature's Answer, Liquid Tart Cherry, 8 fl oz (240 ml)
Nature's Answer
50 mg2418.740.156View on iHerb →
14
Oregon's Wild Harvest, Stress Guard, 90 Vegan Capsules
Oregon's Wild Harvest, Stress Guard, 90 Vegan Capsules
Oregon's Wild Harvest
50 mg3027.960.186View on iHerb →
15
MaryRuth's, Sleep Dissolving Strips, Cranberry, 30 Strips
MaryRuth's, Sleep Dissolving Strips, Cranberry, 30 Strips
MaryRuth's
40 mg3024.990.208View on iHerb →
16
MaryRuth's, Energy Dissolving Strips, Strawberry, 30 Strips
MaryRuth's, Energy Dissolving Strips, Strawberry, 30 Strips
MaryRuth's
40 mg3024.990.208View on iHerb →
17
Revive, Blood Pressure, 180 Vegetarian Capsules
Revive, Blood Pressure, 180 Vegetarian Capsules
Revive
25 mg6049.990.333View on iHerb →

How we rank Suntheanine? L-Theanine

Two supplements can list the same dose per serving yet cost very differently once you account for how many servings are in the bottle. We calculate the total nutrient in each container (dose per serving × servings per container), divide the current price by that total, and rank by the resulting cost per unit. Lower is better. Because prices are refreshed automatically, this ranking reflects today's iHerb pricing rather than a snapshot from months ago.

Cost per unit is a starting point, not the whole story — the ideal form, third-party testing, and other ingredients matter too. Always check the label and consult a healthcare professional before starting a supplement.

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Prices update automatically and may differ from iHerb at checkout. Rankings are based on cost per unit of the listed nutrient and are for informational purposes only — not medical advice. Links to iHerb are affiliate links.