Is a higher dose always better?

No. Dose-fit rewards landing inside the range studied for the outcome — over-dosing (common with melatonin) or under-dosing both lower the score. The goal is the effective dose, not the biggest number.

What does the Value score mean?

The Value score compares a product's price per serving with clinically relevant products ranked for the same outcome. A score of 50 is the typical price; above 50 means better value than typical, while below 50 means the product costs more than typical. It is a 0–100 value signal, not a percentile.

Why is the cheapest product not #1?

Cost is only one input. The cheapest pick here is a citrate form with weaker absorption and a stock-risk flag, so it leads on Value-for-cost but trails on the composite that also weighs evidence, dose fit and availability.

Are these affiliate links?

Retailer links may be affiliate links and DoseRank may earn a commission. Rankings and placement are determined by the scoring model only — never by payment from a brand.

Is this medical advice?

No. DoseRank summarizes evidence to help you choose; it is not a substitute for a clinician, especially if you are pregnant, breastfeeding, on medication, or managing a health condition.

Reduce fatigue

What this outcome means

Fatigue is a persistent sense of tiredness and low stamina that lingers even after rest and makes everyday effort feel harder. On DoseRank it maps to a defined health outcome built from human studies on validated fatigue scales, perceived energy levels, and exertion tolerance – data sourced from open sources and specialized resources. DoseRank is not medical advice.

Who it's for

Afternoon crashEnergy that drains away by mid-day most days.

Run-down and drainedHeavy, depleted tiredness that rest does not fully lift.

Low staminaTiring quickly during tasks that once felt manageable.

Stack buildersAlready taking supplements such as Caffeine Anhydrous and want the dose right.

Evidence level

92Strong

Caffeine Anhydrous – has strong public evidence. DoseRank looks at both evidence quality and formula fit. A DoseFit Score of 67 means this product's ingredient forms and doses are close to what was used in the studies behind this ranking - DoseRank weights each product ingredient.

Best ingredients

Caffeine Anhydrous is the best supported ingredient signal for this outcome.

Dose partly matchedDoseFit 67

Scores reward products dosed inside or above the studied range, not just the right ingredient. Examples: In range: Caffeine Anhydrous 100 mg vs 100-400 mg.

Processed

8.8k

Available

8.8k

Ingredients

Brands

591

Coverage

100%

How to read the scores

What every metric means

Each score is 0–100. Higher is better for every metric below.

CompositeThe overall DoseRank score — a weighted blend of clinical strength, evidence, dose fit, trust and value.Higher is better

ClinicalHow strongly the formula's ingredients and doses match what clinical studies used for this outcome.Higher is better

EvidenceHow much published human research backs the formula's key ingredients for this outcome — both how many studies exist and how strong they are.Higher is better

ValueHow the price per serving compares with similar products for this outcome — 50 is the typical price, higher means better value for your money.Higher is better

TrustHow well customers rate this product, with extra weight given to ratings backed by a large number of reviews.Higher is better

PopularityHow strongly this product sells compared with the other ranked products for this outcome.Higher is better

This legend covers the scores on this page — for data sources, scoring weights, and limits, read the full methodology →

Not sure which is right for you?

Answer a few questions about your goals, habits, stack, and budget. Then, DoseRank will find the products that best match your needs based on your answers. It's free and only takes 60 seconds! No account is required.

Take 60-sec quiz

Get a personal report

A saved, shareable breakdown: your matched products, dose math, interaction flags to discuss with a clinician, and a price-tracked stack you can revisit.

Questions

Frequently asked

Each product gets a composite score blending clinical strength, evidence, dose fit, trust and value. The #1 on the DoseRank tab has the highest composite; the other tabs re-rank the same products by Value, Trust, or Popularity. Placement is never paid.

Reduce fatigue

What this outcome means

Who it's for

Afternoon crashEnergy that drains away by mid-day most days.

Run-down and drainedHeavy, depleted tiredness that rest does not fully lift.

Low staminaTiring quickly during tasks that once felt manageable.

Stack buildersAlready taking supplements such as Caffeine Anhydrous and want the dose right.

Evidence level

92Strong

Best ingredients

Caffeine Anhydrous is the best supported ingredient signal for this outcome.

Dose partly matchedDoseFit 67

Scores reward products dosed inside or above the studied range, not just the right ingredient. Examples: In range: Caffeine Anhydrous 100 mg vs 100-400 mg.

Processed

8.8k

Available

8.8k

Ingredients

Brands

591

Coverage

100%

Relevant ingredients

Which ingredient types matter for fatigueOpen to see which ingredient types matter for fatigue

8.5k products across 6 ingredient types — open to filter the ranking.

Use types to filter ranked products

Alkaloids & Stimulants

229 products

Plant-derived nitrogen compounds like caffeine that stimulate the nervous system. Effective but dose-sensitive, with real tolerance and dependence risk.

Typical:

Botanicals/Herbal Extracts

520 products

Concentrated plant and herbal extracts standardized to actives. Potency depends on the extract ratio and marker content, not raw weight.

Typical: , ,

Minerals & Trace Elements

2.7k products

Inorganic nutrients from calcium to zinc. The chemical form drives absorption – chelates and citrates usually beat cheap oxides.

Typical: ,

Amino Acids & Derivatives

998 products

The building blocks of protein, taken singly for targeted effects – leucine for muscle, theanine for calm. Free-form versions absorb fast on an empty stomach.

Vitamins

3.4k products

Essential micronutrients the body can't make in sufficient amounts. Fat-soluble ones (A, D, E, K) store up; water-soluble ones need regular topping-up.

Antioxidants & Bioactive Compounds

605 products

Molecules that neutralize free radicals and tune cell signaling. Helpful in balance; mega-doses can blunt the body's own adaptive defenses.

Top decision cards

Best products for fatigue

Ranking by · Composite outcome score

Best overall — the composite outcome score.

Top pick · DoseRank

Why this ranks #1 for fatigue

Nutricost, Caffeine with L-Theanine, 240 Capsules

Nutricost$0.05 / serving4.8 · 973Available now

Also helps with

Reaction time

Alertness

Calmness or relaxation

Why this ranks here

Evidence fitCaffeine Anhydrous is the strongest evidence signal for this outcome.
Dose fitCaffeine Anhydrous at 100 mg lands inside the studied 100-400 mg window.
Price / serving$0.05 per serving — low price tier for this outcome.
AvailabilityIn stock across major retailers; 99% availability confidence.
TrustSolid trust signals from buyer ratings, with room to grow.

The numbers

100 mgIn rangeinside the studied 100-400 mg window

100 mg

Compare top 3 Product data Open at retailer

The rest of the ranking · DoseRank

Top 10 ranked products

Force Factor, ProbioSlim®, Weight Loss Essentials, 120 Vegetable Capsules

Force FactorClinical88Dose fit67Popularity96$0.15/ serving

Swanson Vitamins, Full Spectrum® Rhodiola Rosea Root, 400 mg, 100 Vegan Capsules

Swanson VitaminsClinical88Dose fit78Popularity91$0.12/ serving

California Gold Nutrition, TheanineUP®, L-Theanine & Caffeine Plus Cocoa and Matcha, 60 Veggie Capsules

California Gold NutritionClinical88Dose fit67Popularity91$0.19/ serving

Nutricost, Guarana Powder, 3.5 oz (100 g)

NutricostClinical89Dose fit76Popularity68$0.14/ serving

Applied Nutrition, Green Tea Fat Burner®, 90 Fast-Acting Liquid Soft-Gels

Applied NutritionClinical89Dose fit71Popularity84$0.36/ serving

Micro Ingredients, Bariatric Multivitamin, 240 Vegetarian Capsules

Micro IngredientsClinical91Dose fit77Popularity68$0.22/ serving

MuscleTech, Hardcore® Elite, 110 Rapid-Release Thermo Caps

MuscleTechClinical89Dose fit78Popularity80$0.49/ serving

NOW Foods, Panax Ginseng, 500 mg, 250 Veg Capsules

NOW FoodsClinical86Dose fit77Popularity89$0.20/ serving

Nutricost, Women, Pre-Workout Complex With Vitamin B12 & Folate, Blue Raspberry, 12.2 oz (342 g)

NutricostClinical94Dose fit72Popularity30$0.67/ serving