Citrulline (L-citrulline, pure form)
What it is
Converted to arginine in the kidneys, then to nitric oxide for vasodilation. More effective at raising blood arginine than arginine supplements themselves because it bypasses first-pass liver metabolism. Meta-analyses (Mirenayat 2020; Barkhidarian 2019) of short-term RCTs report small-to-moderate reductions in systolic and diastolic blood pressure with 3–6 g/day, though effects in untreated normotensives are less clear. Also improves exercise blood flow and reduces post-exercise muscle soreness. Very safe.
Dose
3–6 g/day L-citrulline for blood pressure; 6–8 g/day 30–60 min before exercise for performance
Time of day & tips
Take on an empty stomach for best absorption. For exercise, take 30–60 min before training. Can be combined with beetroot juice for additive nitric oxide support. Unflavoured powder is the most cost-effective form.
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