The short answer · Perceived exertion
Take caffeine anhydrous for perceived exertion. This is the one to buy.

Applied Nutrition, Green Tea Fat Burner®, 90 Fast-Acting Liquid Soft-Gels
4.2· 6,990 ratings· $0.36/serving
Caffeine Anhydrous 160 mg — inside the studied 150-600 mg window
Of 251 products scored for Perceived exertion, Applied Nutrition, Green Tea Fat Burner®, 90 Fast-Acting Liquid Soft-Gels ranks #1 with a DoseRank score of 84. Caffeine Anhydrous is the strongest evidence signal for this outcome.
Retailer links may be affiliate links. Rankings and placement are never paid.
The form“Why Caffeine Anhydrous?”Evidence Strong evidence
Caffeine Anhydrous is the strongest evidence signal for this outcome.
- Caffeine AnhydrousThe pick
Strong evidence · 160 mg
Dehydrated, water-free caffeine; delivers a precise, fast-acting stimulant dose, which is why it dominates pre-workout and weight-management formulas.
The dose“Is the dose actually effective?”Dose fit 67
Caffeine Anhydrous at 160 mg lands inside the studied 150-600 mg window.
Caffeine Anhydrous
Studied window 150-600 mg · this pick 160 mg
The ranking“Why should I trust this pick?”Trust 80
Solid trust signals from buyer ratings, with room to grow. Each product gets a DoseRank score blending clinical strength, evidence, dose fit, trust and value. Retailer links may be affiliate links — the scoring model decides placement, never payment from a brand.
- 251 products scored
- Never paid placement
- Evidence level: Strong · 92
- 90 brands
- 1 ingredients
The price“Can I do better than $0.36 a serving?”Value 69
$0.36 per serving — mid price tier for this outcome. The cheapest ranked pick here is $0.08 per serving.
- 3Nutricost, Caffeine, 200 mg, 120 CapsulesScore 83 · $0.08/servingiHerb
- 4Nutricost, Guarana Powder, 3.5 oz (100 g)Score 82 · $0.14/servingiHerb
Why not the absolute cheapest? The DoseRank score also weighs clinical strength, evidence, dose fit and trust — the very cheapest listings rarely hold up everywhere else.
Ready?
The #1 pick is $0.36 a serving.Applied Nutrition, Green Tea Fat Burner®, 90 Fast-Acting Liquid Soft-Gels — in stock at a tracked retailer.
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Applied Nutrition, Green Tea Fat Burner®, 90 Fast-Acting Liquid Soft-Gels ranks #1 for Perceived exertion with a DoseRank score of 84. The score blends clinical strength, evidence, dose fit, trust signals and value across 251 products scored for this outcome.