MitoQ
MitoQ. A ubiquinone head group tethered by a ten-carbon chain to a lipophilic triphenylphosphonium cation; the mitochondrial membrane potential drives the cation to…
A ubiquinone head group tethered by a ten-carbon chain to a lipophilic triphenylphosphonium cation; the mitochondrial membrane potential drives the cation to accumulate in the inner mitochondrial membrane, where the respiratory chain reduces it to the antioxidant quinol that scavenges mitochondrial lipid peroxyl radicals. PMID:20492507 verbatim: "The mitochondria-targeted anti-oxidant mitoquinone combines a potent anti-oxidant with a lipophilic cation that causes it to accumulate several-hundred fold within mitochondria in vivo." The same caution this catalog records on `skq1` applies to that accumulation figure: such numbers are typically the authors' calculation from an assumed membrane potential rather than a measurement. THERE IS NO RECEPTOR, so no occupancy row could exist even in principle.
THE STORED MASS IS THE CATION, AND THE NAME ITSELF IS THE TRAP. PubChem `mitoquinone` returns CID 11388332, C37H44O4P+ at 583.7 — note the explicit `+`, a permanently charged triphenylphosphonium species, so there is no neutral free base and "free cation" is the correct term. PubChem `MitoQ` and `mitoquinone mesylate` BOTH return the salt, CID 11388331, C38H47O7PS at 678.8. All re-queried 2026-09-26. The counter-ion follows from the difference between the two fetched formulae, C38H47O7PS minus C37H44O4P = CH3O3S, one methanesulfonate, a 1:1 monovalent salt matching the single cationic charge. The cation is the active species and is what is stored; 583.7 / 678.8 = 0.860 is the cation fraction by mass. NO dose_moiety_fraction IS SET, DELIBERATELY: not one source states whether the 20, 40, 80 or 160 mg human doses are salt or cation, and MitoQ is a supplement with no FDA label to settle it, so applying 0.860 silently would invent the very fact that is missing (R10). THE CLOSEST THING TO HUMAN PK, AND WHY IT IS NOT A VALUE: PMID:29661838 measured plasma MitoQ in 20 older adults and reports only "plasma MitoQ was higher after the treatment versus placebo period (P<0.05)" — a direction and a p-value. Its full text was read (PMC5945293, body element confirmed) and the number exists ONLY inside Figure 1, in no sentence and no table, so reading it out would be the figure-legend defect R2 names. The authors themselves describe that sample as a 24-26 h trough that "likely represent the lowest values achieved", at 6-week steady state, so it would not license a volume even if printed. Its two citations for the known-pharmacokinetic-profile claim are both reviews, and the one fetched (PMID:20649545) prints no number — the SSRI-to-paroxetine-review pattern. DOSES, verbatim: "6 weeks of oral supplementation with MitoQ (20 mg/d)" with an acute "supratherapeutic MitoQ [160 mg]" arm (PMID:29661838), and "mitoquinone (40 or 80 mg) or placebo once daily for 28 days" in 30 chronic hepatitis C patients (PMID:20492507). The Parkinson's PROTECT trial (PMID:20568096) was negative — "no difference between MitoQ and placebo on any measure of PD progression" — and does not state its doses numerically.
Sources: PMID:29661838, PMID:20492507, PMID:20568096, PMID:20649545