MemoHoney Ingredients: all six, and the dose each one was tested at

What it is. An amino acid the body can normally make for itself and sometimes cannot, and the raw material nitric oxide synthase works on directly.

What the trials used. The 2022 dose-response meta-analysis found blood pressure moved at four grams a day and above, with nothing further gained past nine grams (the 2022 dose-response meta-analysis). A 2026 reassessment using ambulatory monitoring rather than clinic readings narrowed the estimate again (a 2026 reassessment using ambulatory monitoring).

The catch. Oral arginine is heavily metabolised in the gut wall and liver before it reaches the bloodstream. A 2009 meta-analysis found the vascular benefit was measurable mainly in people whose baseline function was already impaired (a 2009 meta-analysis of vascular function), and a later review in cardiovascular and metabolic patients reached a similar place (a 2018 review of endothelial markers).

What it is. Two parts L-arginine to one part alpha-ketoglutarate, a Krebs-cycle intermediate. Sold on the theory that the pairing survives the gut better than arginine alone.

What the trial used. Four grams three times a day, twelve grams in total, in trained men over eight weeks, with pharmacokinetics and safety measured alongside performance (the arginine AKG trial).

What it found. The compound was tolerated and plasma arginine rose. Performance effects were limited and inconsistent. Twelve grams a day is the figure to carry into the dose table below.

What it is. The amino acid the kidney converts into arginine, which is why it raises plasma arginine more reliably than arginine taken by mouth.

What the trial used. Three grams twice a day. In the crossover study that established this, the six-gram daily arm lifted the trough plasma arginine concentration and improved the arginine to ADMA ratio; the lower arm did not (the 2008 pharmacokinetic study).

Why it matters here. This is the technically best decision on the label. Whoever chose two citrulline rows over more arginine understood the first-pass problem, and that deserves saying.

What it is. The form the sports shelf sells, usually as two parts citrulline to one part malic acid.

What the trials used. A meta-analysis of resistance-trained adults pooled doses around eight grams and found a small effect on strength (the citrulline malate strength meta-analysis). A 2025 crossover gave 5.3 g of citrulline with and without 2.7 g of malate and found the malate contributed nothing beyond the citrulline itself (the 2025 head-to-head trial of the two forms).

What follows. Two citrulline rows on one label are two ways of delivering one compound, not two compounds.

What it is. The precursor of NAD, the cofactor every cell uses to release energy from food. Severe deficiency causes pellagra, whose third symptom is a dementia that reverses when the vitamin is replaced.

The amounts that matter. An adult needs 14 to 16 mg a day. The tolerable upper intake level for added niacin is 35 mg, above which flushing becomes common (the NIH Office of Dietary Supplements niacin fact sheet).

The cognition evidence. Higher dietary niacin tracked with fewer cases of Alzheimer's disease and slower decline over six years in the Chicago Health and Aging Project (the Chicago Health and Aging Project analysis), and a separate cohort followed intake from young adulthood into midlife (the CARDIA midlife cognition study). Both are observations about what people ate, not trials of a capsule.

What it is. The rate-limiting precursor for carnosine, a dipeptide that buffers acid inside muscle fibres. It is bought by cyclists and rowers, not by people who forget names.

What the trials used. Four to six grams a day for at least four weeks to raise muscle carnosine, per the sports nutrition position stand (the sports nutrition position stand). A 2017 comparison pushed twelve grams a day of a sustained-release form to load faster while blunting the tingle (a 2017 comparison of two dosing protocols).

The cognition studies. Twelve grams a day for a fortnight, given to soldiers before simulated operational stress (the 2021 cognition and mood trial, the 24-hour operation trial). The review of that literature describes resilience and mood findings rather than better memory (a 2023 review of the soldier studies).