Acetyl-L-Carnitine

Acetylated form of L-carnitine that crosses the blood-brain barrier to support cognitive function, energy production, and neuroprotection

Scientific nameN-Acetyl-L-carnitine FormulaC9H17NO4 Molecular weight203.24 g/mol CAS5080-50-2

95 absorption score

8 safety / 10

40 USD per month

5 documented interactions

Check it against something

Evidence level A

Acetyl-L-Carnitine with:

82 out of 100

Works better together Compatible. Timing differs, so follow each supplement's own window.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Enhanced cognitive function and memory

Improves memory, learning, and overall cognitive performance

Supports mitochondrial function in brain cells and acetylcholine production Evidence B-grade 2-8 weeks

Increased mental energy and focus

Boosts mental energy and improves concentration

Enhances brain mitochondrial energy production and neurotransmitter synthesis Evidence B-grade 1-4 weeks

Neuroprotection and brain health

Protects brain cells from aging and oxidative damage

Antioxidant effects and supports nerve growth factor production Evidence B-grade 4-12 weeks

Mood enhancement and depression support

May improve mood and reduce symptoms of depression

Supports neurotransmitter production and brain energy metabolism Evidence C-grade 4-8 weeks

Peripheral neuropathy relief

May help with nerve pain and diabetic neuropathy

Supports nerve cell energy and promotes nerve regeneration Evidence B-grade 8-16 weeks

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Creatine Monohydrate Strength & power enhancement 3-5g A 95% Calcium Bone health & muscle function 1,000-1,200 mg A 30% Ashwagandha Stress management & energy 300-600mg A 75% Magnesium Glycinate Superior absorption sleep & muscle support 200-600 mg A 90% Vitamin B12 (Cyanocobalamin) Energy & nerve support 250-1000 mcg A 70% Coenzyme Q10 (CoQ10) Heart health & cellular energy 100-200mg A 10%

Every pair we checked

12 combinations scored by the engine

Acetyl-L-Carnitine + Caffeine No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Creatine Monohydrate No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Vitamin D3 No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Calcium Carbonate No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Whey Protein No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Lactase No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Bovine Collagen No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + DHA No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Turmeric No documented interaction either way No known interaction 70

Acetyl-L-Carnitine + Coenzyme Q10 (CoQ10) Enhanced cellular energy and brain function Works better together 78

Acetyl-L-Carnitine + Alpha-Lipoic Acid (ALA) Enhanced mitochondrial function and neuroprotection Works better together 82

Acetyl-L-Carnitine + Phosphatidylserine Enhanced memory and cognitive function Works better together 86

Dosage

Morning empty stomach

Daily1000-3000mg

Cognitive enhancement1000-2000mg daily

Neuroprotection1500-3000mg daily

Mood support1000-2000mg daily

Neuropathy support2000-3000mg daily

When to expect it

First Effects1-2 weeks for mental energy and focus

Peak Benefits6-12 weeks for sustained cognitive and neuroprotective benefits

Deficiency DevelopmentGradual decline in mental energy and cognitive function

Toxicity OnsetRare, mainly digestive upset

How to measure it

$100-200

MarkerCarnitine levels or cognitive function tests

OptimalAdequate carnitine levels and improved cognitive markers

Deficient belowLow carnitine levels

FrequencyEvery 6-12 months for cognitive health monitoring

What people actually reported to the FDA

CAERS, 37 reports naming it as the suspect

Most reported effects

Dyspnoea 4

Fatigue 4

Headache 4

Nausea 4

Diarrhoea 4

Named as the suspect 37 reports of 50 that mention it at all

Serious outcome 81% hospitalisation, emergency room or worse

Other Serious or Important Medical Event21

Hospitalization16

Visited Emergency Room15

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

What actually reaches you

The label counts the carrier, your body does not

Absorption Very high 95 of 100 · best absorbed form of this compound

Delivered daily 1900 mg

Cost per 100 mg delivered $0.07 comparative — uses the absorption score, not a measured percentage

Works better with

3 documented

Alpha Lipoic Acid

Enhanced mitochondrial function and neuroprotection

Both support mitochondrial energy and antioxidant protection · level A

Coq10

Enhanced cellular energy and brain function

Both support mitochondrial energy production · level B

Phosphatidylserine

Enhanced memory and cognitive function

Both support brain cell membrane function and neurotransmitters · level B

What not to take with Acetyl-L-Carnitine

2 documented

Alcohol Excess

Alcohol impairs brain function and mitochondria

Alcohol damages brain cells and reduces cognitive benefits · moderate significance

Anticonvulsants

Some seizure medications may reduce carnitine levels

Certain drugs deplete carnitine stores · moderate significance

Medication interactions

Discuss these with a pharmacist before combining

thyroid-medications Minor

May enhance thyroid hormone effects

What to do: Monitor thyroid function

anticoagulants Minor

May have mild anticoagulant effects

What to do: Monitor bleeding parameters

stimulants Minor

May enhance stimulant effects

What to do: Monitor for overstimulation

Available forms

bioavailability compared

Acetyl-L-Carnitine HCl 95

Acetyl-L-Carnitine HCl: Brain penetration, Cognitive support, High bioavailability, Well-researched

Food sources

before you supplement

Red meat (especially lamb) Highest dietary source · 75

Dairy products Moderate amounts · 70

Fish and poultry Good sources · 70

ALCAR supplements 500-1000mg per capsule · 95

Too little

deficiency signs

Mental fatigue and brain fog
Poor memory and concentration
Age-related cognitive decline
Depression and low mood
Nerve pain and neuropathy
Poor mental energy and motivation
Difficulty learning new information

Too much

toxicity signs

Generally safe but potential effects:
Nausea and digestive upset
Restlessness and overstimulation
Insomnia if taken late in day
Fishy body odor in some individuals

Who benefits most

cognitive-enhancement-memory

Excellent for improving memory, focus, and mental clarity

1000-2000mg daily

aging-adults-cognitive-decline

May help prevent or reverse age-related cognitive decline

1500-3000mg daily

students-mental-performance

Enhances learning, memory, and mental energy

1000-2000mg daily

depression-mood-support

May improve mood and energy in depression

1000-2000mg daily

diabetic-neuropathy

May help with nerve pain and diabetic complications

2000-3000mg daily

Where to buy it

compare forms first

Look for Acetyl-L-Carnitine at 1000-3000mg per serving. The form that matters here is Acetyl-L-Carnitine HCl.

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What else affects it

Beyond other supplements

Alcohol excess

Alcohol impairs brain function and mitochondria

Alcohol damages brain cells and reduces cognitive benefits

How it works

Crosses blood-brain barrier providing carnitine to brain mitochondria
Enhances acetylcholine synthesis supporting memory and learning
Improves mitochondrial energy production in brain cells
Provides antioxidant protection against neuronal damage
Supports nerve growth factor (NGF) production
Enhances neurotransmitter synthesis and brain metabolism

Key findings

what the evidence supports

Good evidence for cognitive enhancement and neuroprotection
May help with age-related cognitive decline and dementia
Effective for diabetic neuropathy and nerve pain
Generally safe with excellent bioavailability

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of Acetyl-L-Carnitine?

Documented effects: Enhanced cognitive function and memory; Increased mental energy and focus; Neuroprotection and brain health; Mood enhancement and depression support. Improves memory, learning, and overall cognitive performance

How much Acetyl-L-Carnitine should you take per day?

The common daily range is 1000-3000mg. By goal — cognitive enhancement: 1000-2000mg daily; neuroprotection: 1500-3000mg daily; mood support: 1000-2000mg daily; neuropathy support: 2000-3000mg daily.

When is the best time to take Acetyl-L-Carnitine?

Morning empty stomach. First effects are typically reported within 1-2 weeks for mental energy and focus.

What are the side effects of Acetyl-L-Carnitine?

At excessive doses: Generally safe but potential effects:, Nausea and digestive upset, Restlessness and overstimulation, Insomnia if taken late in day, Fishy body odor in some individuals. Safety rating at normal doses is 8 out of 10.

What should you not take with Acetyl-L-Carnitine?

Separate it from Alcohol Excess, Anticonvulsants by two to four hours. Alcohol impairs brain function and mitochondria

Does Acetyl-L-Carnitine interact with medications?

Documented interactions with thyroid-medications, anticoagulants, stimulants. Discuss these with a pharmacist before combining.

How do you know if you need Acetyl-L-Carnitine?

The marker is Carnitine levels or cognitive function tests, optimal range Adequate carnitine levels and improved cognitive markers. Common deficiency signs: Mental fatigue and brain fog, Poor memory and concentration, Age-related cognitive decline, Depression and low mood.

Taken for

52 Brain & Focus

Caffeine · DHA · Fish Oil (EPA/DHA)

62 Energy & Metabolism

Vitamin B12 (Methylcobalamin) · Ashwagandha · Vitamin B12 (Cyanocobalamin)

43 Performance

Caffeine · Creatine Monohydrate · Whey Protein