Nootropic
Acetyl-L-Carnitine (ALCAR)
Also known as: ALC, Acetyl L-Carnitine HCl, ALCAR, Acetyl-L-Carnitine
Acetyl L-Carnitine is a form of carnitine that crosses the blood-brain barrier and supports mitochondrial energy production and acetylcholine synthesis. It has shown modest benefits for cognitive function and energy metabolism in some studies, with stronger evidence in elderly populations and carnitine-deficient states.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Acetyl-L-Carnitine (ALCAR) product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Nootropics Depot Acetyl L-Carnitine HCL (ALCAR) Capsules | 94 A | $0.22 |
| 2 | Nutricost Acetyl L-Carnitine Powder | 94 A | $0.08 |
| 3 | Nootropics Depot Acetyl L-Carnitine ALCAR Powder | 94 A | — |
| 4 | Jarrow Formulas Acetyl L-Carnitine 500 mg | 94 A | $0.38 |
| 5 | Momentous Acetyl L-Carnitine | 94 A | $0.50 |
| 6 | NutraBio Acetyl L-Carnitine (500mg) | 94 A | $0.44 |
| 7 | Thorne Acetyl-L-Carnitine | 92 A | $0.53 |
| 8 | Pure Encapsulations Acetyl-l-Carnitine | 92 A | $0.75 |
| 9 | Natural Factors Acetyl-L-Carnitine | 92 A | $0.70 |
| 10 | Pure Encapsulations Cognitive Aminos | 91 A | $0.98 |
| 11 | Pure Encapsulations CogniPhos | 91 A | $1.25 |
| 12 | Pure Encapsulations MotilPro | 90 A | $1.10 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Acetyl-L-Carnitine (ALCAR) should I take?
The typical range is 500-2000 mg daily. Safe long-term
When should I take Acetyl-L-Carnitine (ALCAR)?
Morning (mildly stimulating). Optional.
Which form of Acetyl-L-Carnitine (ALCAR) is best?
Capsules — Common. Other forms in the catalog: Powder, HCl salt (hydrochloride), Tablets.
Is Acetyl-L-Carnitine (ALCAR) safe?
Commonly reported: GI upset, Fishy odor, Insomnia if late. Serious warnings: None significant. Safe
Which Acetyl-L-Carnitine (ALCAR) supplement scores highest?
Nootropics Depot Acetyl L-Carnitine HCL (ALCAR) Capsules, at 94/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Daily target & upper limit
1000 mg / dayAcetyl-L-Carnitine (ALCAR) has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Acetyl-L-Carnitine (ALCAR) dosage reference →Primary uses
- Brain energy
- Memory
- Neuroprotection
- Mood
- Cognitive support
- Energy and fatigue
- Age-related cognitive decline
What systematic reviews concluded
Outcomes that systematic reviews of Acetyl-L-Carnitine (ALCAR) reached a verdict on: 6 with a benefit, 1 with no effect, 1 unclear. Each is quoted from a review and linked to it on PubMed. How these were read.
Reviews found a benefit (6)
“L-carnitine (2 g/day) and acetyl-L-carnitine (LAC; 1 g/day) combined (SMD 0.57 for asthenozoospermia)” PMID 31160241 · 2 reviews
“L-Arginine and the mix PLC + ALC appeared to be of some usefulness in improving erectile function, especially in combination with PDE5i in organic ED.” PMID 39279185
“The current evidence suggests that ALC has a moderate effect in reducing pain measured on VAS in PNP patients with acceptable safety.” PMID 25751285
“Supplementation with Chlorella green algae, coenzyme Q10, acetyl-l-carnitine or a combination of vitamin C and E significantly improved measures of pain.” PMID 32878326
“ALC supplementation significantly decreases depressive symptoms compared with placebo/no intervention” PMID 29076953
“Acetyl-L-carnitine reduces blood ammonium levels compared with placebo.” PMID 30610762
Reviews found no effect (1)
“We found no clear differences in effect between acetyl-L-carnitine and placebo regarding quality of life, fatigue, and non-serious adverse events.” PMID 30610762
Not enough to say: diabetic peripheral neuropathy pain.
1 finding from reviews in specific patient groups (such as cancer, pregnancy or surgery) is not shown here.
How it works
- Crosses BBB
- Acetyl donor for acetylcholine
- Supports mitochondrial function in brain
Dosage
- Typical range
- 500-2000 mg daily
- Timing
- Morning (mildly stimulating)
- With food
- Optional
- Duration
- Safe long-term
- Special populations
- Cognitive aging, depression
Forms
- Capsules
- Powder
- HCl salt (hydrochloride)· 70/100
- Tablets· 70/100
Safety
Common side effects
- GI upset
- Fishy odor
- Insomnia if late
Contraindications
- Seizure disorders (caution)
Products containing Acetyl-L-Carnitine (ALCAR)
Top-scoring supplements in our catalog that list Acetyl-L-Carnitine (ALCAR) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Brain-penetrating carnitine
Grade B: Some human trials support key claims; further confirmation needed.
Cited research for Acetyl-L-Carnitine (ALCAR)
Clinical studies referenced across Formulate guides that mention acetyl-l-carnitine (alcar). Each links to the full study page with PubMed source + the guides that cite it.
- Sima AA, Calvani M, Mehra M, Amato A (2005)Diabetes Care
Acetyl-L-carnitine for the treatment of diabetic peripheral neuropathy: a long-term, randomised, double-blind, placebo-controlled study
- Montgomery SA, Thal LJ, Amrein R (2003)International Clinical Psychopharmacology
Acetyl-L-carnitine for the treatment of mild cognitive impairment and mild Alzheimer's disease: a meta-analysis of clinical trials
Acetyl-L-Carnitine (ALCAR) compared head-to-head
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.