Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.
| Alpha Lipoic Acid (ALA) | L-Carnitine (ALCAR / Acetyl-L-Carnitine) | |
|---|---|---|
| Category | Supplements | Amino Acids |
| Standard Dose | 300-600mg R-ALA daily | 500-2000mg ALCAR daily or 1000-3000mg L-Carnitine L-Tartrate (for exercise performance) |
| Timing | On empty stomach, 30-60 min before meals. Split doses for higher amounts. | Morning on empty stomach for cognitive effects. Pre-workout for fat oxidation/performance. ALCAR for brain; L-Carnitine L-Tartrate for muscle/exercise. |
| Cycle Duration | ongoing or cycle 12 weeks on, 4 weeks off | ongoing |
| Evidence Level | strong_human | strong_human |
ALA is a dithiol compound that functions as a cofactor for mitochondrial alpha-keto acid dehydrogenases (pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase). Both ALA and its reduced form DHLA are potent antioxidants capable of regenerating other antioxidants including vitamin C, vitamin E, and glutathione. ALA activates AMPK, improving glucose uptake via GLUT4 translocation, and modulates NF-kB-mediated inflammatory signaling. It chelates redox-active metals (Fe2+, Cu2+).
300-600mg R-ALA daily
On empty stomach, 30-60 min before meals. Split doses for higher amounts.
ongoing or cycle 12 weeks on, 4 weeks off
L-Carnitine's primary function is transporting long-chain fatty acids across the inner mitochondrial membrane via the carnitine shuttle (CPT-I/CPT-II system) for beta-oxidation. Acetyl-L-Carnitine (ALCAR) additionally donates its acetyl group to form acetyl-CoA (bypassing pyruvate dehydrogenase) and serves as a precursor for acetylcholine synthesis. ALCAR crosses the blood-brain barrier, providing neuroprotective effects through mitochondrial energetics, reduction of lipofuscin accumulation, enhancement of NGF receptor sensitivity, and modulation of synaptic plasticity. It also reduces oxidative stress via upregulation of heme oxygenase-1.
500-2000mg ALCAR daily or 1000-3000mg L-Carnitine L-Tartrate (for exercise performance)
Morning on empty stomach for cognitive effects. Pre-workout for fat oxidation/performance. ALCAR for brain; L-Carnitine L-Tartrate for muscle/exercise.
ongoing
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