Quick Comparison
| ALCAR | Maca Root | |
|---|---|---|
| Half-Life | 4-5 hours | Bioactive compounds accumulate with daily use |
| Typical Dosage | Standard: 500-2000 mg daily in 1-2 doses. For cognitive support: 1000-2000 mg daily. For neuropathy: 1500-3000 mg daily. Take in the morning — may be mildly stimulating. | Standard: 1500-3000 mg daily of extract (or 5-10 grams of raw powder). Red maca: best for prostate health and bone density. Black maca: best for cognition, endurance, and sperm quality. Yellow maca: most common, general adaptogen. Gelatinized maca is easier to digest. Take in the morning. Effects build over 2-6 weeks. |
| Administration | Oral (capsules, powder). Well-absorbed on an empty stomach. | Oral (capsules, powder). Gelatinized for better digestion. Take in the morning. |
| Research Papers | 9 papers | 10 papers |
| Categories |
Mechanism of Action
ALCAR
ALCAR crosses the blood-brain barrier via the organic cation transporter (OCTN2) more effectively than L-carnitine. In neurons, it is hydrolyzed by carnitine acetyltransferase to donate its acetyl group to coenzyme A, forming acetyl-CoA—which can then be used for acetylcholine synthesis via choline acetyltransferase, effectively providing raw material for the memory neurotransmitter. ALCAR also transports long-chain fatty acids across the inner mitochondrial membrane via the carnitine palmitoyltransferase system for beta-oxidation and ATP production. ALCAR activates nerve growth factor (NGF) signaling, possibly through modulation of NGF receptor (TrkA) expression or downstream MAPK/ERK pathways. It has antioxidant properties, reducing lipid peroxidation in mitochondrial membranes and scavenging free radicals. These mechanisms support cognitive function and neuroprotection.
Maca Root
Macamides (N-benzyl fatty acid amides like macamide N-benzylhexadecanamide) and macaenes are unique compounds that inhibit fatty acid amide hydrolase (FAAH), increasing anandamide levels and modulating the endocannabinoid system — providing mood and stress resilience without CB1/CB2 direct activation. Maca improves endocrine signaling through the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes, normalizing CRH, ACTH, and gonadotropin release without directly altering hormone levels. Glucosinolates (glucotropaeolin) support antioxidant defense via Nrf2. The cognitive effects of black maca are attributed to improved cerebral blood flow (possibly via eNOS), acetylcholinesterase (AChE) inhibition increasing acetylcholine, and reduced oxidative stress. The energy effects may involve improved mitochondrial function (Complex I), glucose metabolism (GLUT4, hexokinase), and dopaminergic tone.
Risks & Safety
ALCAR
Common
Nausea, fishy body odor, restlessness, gastrointestinal discomfort.
Serious
May increase agitation in Alzheimer's patients. TMAO production may be a cardiovascular concern with chronic high doses.
Rare
Seizures in susceptible individuals, increased thyroid activity.
Maca Root
Common
GI discomfort with raw powder (gelatinized form is gentler), insomnia if taken late.
Serious
May be contraindicated with hormone-sensitive conditions (theoretical, no direct hormonal activity proven).
Rare
Headache, mood changes. Goitrogen concerns at very high doses.
Full Profiles
ALCAR →
Acetyl-L-Carnitine is an acetylated form of L-Carnitine that crosses the blood-brain barrier more effectively than regular L-Carnitine. In the brain, it donates its acetyl group for acetylcholine synthesis and supports mitochondrial fatty acid oxidation for energy. Used clinically for age-related cognitive decline, depression, and diabetic neuropathy.
Maca Root →
A cruciferous root vegetable (Lepidium meyenii) grown at high altitude in the Peruvian Andes, used for over 2,000 years for energy, stamina, and libido. Maca does not directly modulate hormones — instead it acts on the hypothalamus and pituitary to normalize endocrine function. It improves energy and mood without stimulation, making it a true adaptogen. Different colors (red, black, yellow) have different properties.