Quick Comparison
| Agmatine Sulfate | Rhodiola Rosea | |
|---|---|---|
| Half-Life | 2-3 hours | 6-8 hours (salidroside) |
| Typical Dosage | Standard: 500-2000 mg daily in 1-3 doses. For mood: 1000-2000 mg. For pain: 1000-2500 mg. Take on empty stomach. Agmatine sulfate is the most common supplement form. May enhance the effects of some nootropics and medications — research interactions. | Standard: 200-400 mg daily of extract standardized to 3% rosavins and 1% salidroside. SHR-5 is the most studied extract. Take in the morning — can be mildly stimulating. |
| Administration | Oral (powder, capsules). Take on empty stomach for best absorption. | Oral (capsules, tablets, tincture). Standardized extracts preferred. |
| Research Papers | 10 papers | 10 papers |
| Categories |
Mechanism of Action
Agmatine Sulfate
Agmatine is a polyamine neuromodulator with multiple targets: (1) NMDA receptor antagonist at the polyamine binding site (GluN1/GluN2B) — reduces excitotoxicity, pain signaling, and blocks the receptor's open channel. (2) Imidazoline I1 and I2 receptor agonist — I1 in the rostral ventrolateral medulla reduces sympathetic tone; I2 modulates monoamine oxidase and provides anxiolytic/antidepressant effects. (3) Selective nNOS (neuronal nitric oxide synthase) inhibitor — reduces peroxynitrite formation and oxidative stress while preserving eNOS (endothelial) function for vascular health. (4) Alpha-2 adrenergic receptor agonist — reduces norepinephrine release from locus coeruleus, promoting calm. (5) Modulates opioid receptors — enhances mu-opioid analgesia, potentiates delta-opioid, and may reduce tolerance via nitric oxide and NMDA mechanisms.
Rhodiola Rosea
Rhodiola modulates the hypothalamic-pituitary-adrenal (HPA) axis and reduces cortisol release under stress, possibly through modulation of glucocorticoid receptor sensitivity. Salidroside and rosavins inhibit catechol-O-methyltransferase (COMT) and monoamine oxidase A and B (MAO-A, MAO-B), slowing the breakdown of dopamine, serotonin, and norepinephrine in the brain — increasing catecholamine availability in the prefrontal cortex and limbic system during stress. Rhodiola activates AMP-activated protein kinase (AMPK), a cellular energy sensor that enhances glucose uptake and mitochondrial biogenesis. It has antioxidant effects via activation of Nrf2 and HO-1, protecting neurons from stress-induced oxidative damage. Salidroside may also modulate opioid peptide (beta-endorphin) release and enhance nitric oxide production.
Risks & Safety
Agmatine Sulfate
Common
Mild gastrointestinal discomfort, diarrhea at high doses.
Serious
May potentiate opioid medications (increased sedation risk). May lower blood pressure.
Rare
Headache, nausea.
Rhodiola Rosea
Common
Mild dizziness, dry mouth, jitteriness.
Serious
May have MAOI-like properties at high doses — avoid combining with MAOI medications.
Rare
Insomnia, vivid dreams, agitation.
Full Profiles
Agmatine Sulfate →
A metabolite of L-arginine produced by decarboxylation. Agmatine is an endogenous neuromodulator that acts on multiple receptor systems — it blocks NMDA receptors, activates imidazoline receptors, inhibits nitric oxide synthase, and modulates opioid signaling. This makes it useful for neuropathic pain, mood, stress resilience, and as a complement to other nootropics. Also enhances insulin sensitivity and nitric oxide production.
Rhodiola Rosea →
An arctic adaptogen used traditionally in Scandinavia and Russia for physical endurance and mental resilience. Rhodiola's key compounds, salidroside and rosavin, reduce mental fatigue and improve performance under stress. It is one of the few adaptogens with robust evidence for acute cognitive effects — improvements can be noticed within hours of a single dose.