Acetyl-L-carnitine
Summary
Acetyl-L-carnitine is a carnitine ester. Pooled trials found fewer depressive symptoms than placebo (12 RCTs, grade B) and small gains in mild cognitive impairment. For nerve pain, a 2015 analysis found moderate pain relief, but a 2019 Cochrane review called diabetic nerve-pain evidence very uncertain.
Key facts
- Carnitine with an acetyl group; used to move fatty acids into mitochondria[1]
- Depressive symptoms (12 RCTs, 791 people; grade B)[1]
- A 2003 pooled analysis in MCI and mild Alzheimer disease found a small advantage over placebo (effect size 0.20)[3]
- Cochrane (2019): very uncertain benefit for diabetic nerve pain; manufacturer funding in included trials[4]
- 2 graded human outcomes on this page
- October 11, 2026
How it works
ProposedAcetyl-L-carnitine supplies carnitine for fatty-acid transport into mitochondria and acetyl groups for acetylcholine. Effects on mood and nerves are proposed to involve mitochondrial energy and neurotransmitter support.[1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Mood | Grade B | Improved | Meta-analysis of 12 trials · n = 791 · 2018 | 1 row |
| Nerve pain | Grade C | Improved | Meta-analysis of 4 trials · n = 523 · 2015 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Depressive symptoms | Improved | Grade B | Meta-analysis · n = 791 · 2018 Adults (mean age 54) in 12 RCTs Form: Acetyl-L-carnitine · Dose: Varied across trials · Duration: Varied across trials Depressive symptoms fell versus placebo or no treatment; effects were similar to antidepressants in head-to-head trials, with fewer side effects. | 29076953 (opens PubMed)Source [1] |
| Peripheral nerve pain | Improved | Grade C | Meta-analysis · n = 523 · 2015 Adults with peripheral neuropathic pain in 4 RCTs Form: Acetyl-L-carnitine · Dose: Varied across trials · Duration: Varied across trials Pain on a visual scale fell moderately versus placebo, more clearly in diabetic neuropathy. | 25751285 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Acetyl-L-carnitine HCl | Varies | The form used in most trials cited here; no head-to-head absorption data versus other salts. | Adverse events were similar to placebo in the pooled nerve-pain trials.[2] | Mood, memory and nerve-pain trials |
| Acetyl-L-carnitine arginate | Varies | No outcome trials of this salt in the sources cited here. | No separate tolerance data in the sources cited here. | Sold as a supplement form |
Studied doses
Doses studied in human trials ranged from about 1 g/day to 3 g/day, usually for 3 to 12 months in memory and nerve-pain studies.[1][2][3]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Diabetic nerve pain
- Cochrane judged the evidence very uncertain and noted that included trials were funded by, or had authors tied to, ALC manufacturers.[4]
- Pregnancy and breastfeeding
- The trials cited here enrolled non-pregnant adults.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Where to buy Acetyl-L-carnitine
Products from brands we partner with that contain Acetyl-L-carnitine. Listing a product is not a claim that it works; check the amount per serving against the doses studied above, and the label for other ingredients.
- SupersmartPaid linkAcetyl L-Carnitine Arginate2 capsules: 1,000 mg acetyl-L-carnitine arginate (a different salt from the HCl form used in most trials); 50 servingsShop at Supersmart (opens in new tab)Price and label checked 2026-10-11 on the brand’s site.
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Frequently asked questions
Is acetyl-L-carnitine better than L-carnitine for the brain?
Acetyl-L-carnitine is the form tested in most mood and memory trials; L-carnitine trials focus on exercise and weight.[1]
Does it help depression?
Pooled trials found fewer depressive symptoms than placebo, mostly in older adults. Larger trials are still needed.[1]
Sources
- [1]Acetyl-L-Carnitine Supplementation and the Treatment of Depressive Symptoms: A Systematic Review and Meta-Analysis.. Psychosom Med, 2018. meta-analysis
- [2]Acetyl-L-carnitine in the treatment of peripheral neuropathic pain: a systematic review and meta-analysis of randomized controlled trials.. PLoS One, 2015. meta-analysis
- [3]Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer's disease.. Int Clin Psychopharmacol, 2003. meta-analysis
- [4]Acetyl-L-carnitine for the treatment of diabetic peripheral neuropathy.. Cochrane Database Syst Rev, 2019. systematic-review
What changed
- Corrected the effect arrow (↑ improved, ↓ worsened for participants) on: Depressive symptoms; Peripheral nerve pain.
- First draft. Every PMID checked against NCBI E-utilities (title, journal and year taken from the PubMed record) and each evidence row written from its PubMed abstract.