PQQ or Pyrroloquinoline quinone was first discovered in 1979 as a cofactor for enzyme reactions in bacteria where it serves a similar function to that of B vitamins for humans. This means that PQQ assists enzymes in accomplishing their jobs. There is a class of these cofactor molecules that transfer electrons, which is important for our mitochondria to produce energy.
Natural PQQ Sources
- Fermented soybean products (e.g. Nattō) [R]
- Green soybeans [R]
- Spinach [R]
- Field mustard (5.54 +/-1.50ng/g fresh weight) [R]
- Tofu [R]
- Green tea [R]
- Green peppers [R]
- Parsley [R]
- Kiwi fruits [R]
The PQQ content of even the most PQQ-rich foods is much lower than the amount you can get from a supplement (5 to 20 mg).
In rats, 62% of PQQ was absorbed in the gut when taken with a meal [R]. In rodents, PQQ is mostly (86%) eliminated 24 hours after ingestion. However, some PQQ residues remain in the skin and kidneys [R]. PQQ is almost entirely metabolized before being eliminated and dubbed safe for human consumption [R].
Benefits of PQQ
PQQ Decreases Inflammation and Free Radicals
Healthy humans who took 20 mg of PQQ (for a 150-pound male) had a significant decreases in the levels of C-reactive protein (by 45% after 3 weeks) and IL-6. A lower dosage didn’t decrease inflammation [R]. Various urinary markers of oxidative stress also improved, which is consistent with enhanced mitochondria-related functions.
PQQ Creates New Mitochondria: The Role of PGC-1a
Compounds reported to stimulate mitochondrial biogenesis are linked to many health benefits such as increased longevity, improved energy utilization, and protection from free radicals.
Mice and rats fed diets lacking in pyrroloquinoline quinone (PQQ) have reduced mitochondrial content. The creation of new mitochondria by PQQ occurs through the activation of CREB and PGC-1alpha, pathways known to increase mitochondrial biogenesis [R].
As a result of activation of the PGC-1alpha pathway, PQQ increased NRiF-1 and NRF-2, proteins (transcription factors) that protect us more free radicals by increasing our internal antioxidant production. They also protect us from toxins, UV, etc.
PGC-1a is a “master regulator” that directly stimulates genes that promote mitochondrial and cellular respiration, growth, and proliferation [R]. By increasing cellular metabolism it favorably affects blood pressure, cholesterol, and triglyceride breakdown, and the onset of obesity .
PQQ Improves Memory and Reasoning: The Role of CREB
PQQ Improves Brain Function by Increasing Nerve Growth Factor and Schwann Cells
PQQ supplementation stimulates the production and release of nerve growth factors in cells that support neurons in the brain, a possible mechanism for the improvement of memory function it appears to produce in aging humans and rats [R]. PQQ also Increases Schwann cells by increasing the PI3K/Akt signal pathway [R].
PQQ Is Neuroprotective Against Alzheimer’s, Parkinson’s, and Cognitive Injuries
PQQ is a neuroprotective compound that protects memory and cognition in aging animals and humans , as shown in studies [R]. PQQ increases a protein (DJ-1) that is important to brain health and function. This protein, which increases cell function and survival by combating intensive oxidative stress, is likely important to brain health and function [R].
DJ-1 mutations have been conclusively linked to the onset of rare inherited forms of Parkinson’s disease and other neurological disorders. PQQ suppresses reactive nitrogen species (iNOS causes this), which spikes in strokes and brain injuries. In this manner, it provides protection against neuro-related injuries [R].
In animal models, administration of PQQ immediately prior to induction of stroke significantly reduced the size of the damaged brain area [R]. PQQ also protects neurons by preventing the long-term overactivation of the NMDA receptors, which results in excitotoxicity. Long-term, overstimulation of neurons is associated with many neurodegenerative diseases and seizures [R, R].
It also protects the brain against neurotoxicity induced by other powerful toxins, including mercury and oxidopamine, toxins that are suspected to cause Alzheimer’s and Parkinson’s, respectively [R, R, R, R]. PQQ also prevents aggregation of alpha-synuclein and amyloid-beta, proteins associated with Parkinson’s and Alzheimer’s diseases, respectively [R, R].
It also protects nerve cells from the toxic effects of the proteins that are already there.
PQQ Protects Your Heart Against Stroke
Administration of PQQ reduces the size of damaged areas in animal models of acute heart attack. This occurs irrespective of whether the chemical is given before or after the ischemic event itself, suggesting that administration within the first hours of medical response may offer benefits to heart attack victims [R].
It could be useful to keep this on hand in case loved ones have an incident. Researchers compared PQQ with the standard post-heart attack clinical treatment (metoprolol, a beta blocker). Both treatments reduced the size of the damaged areas and protected against heart muscle dysfunction. Only PQQ favorably reduced cellular damage (lipid peroxidation) and the effects were more significant. These results led the researchers to conclude that “PQQ is superior to metoprolol in protecting mitochondria from ischemia/reperfusion oxidative damage” [R].
PQQ Improves Sleep, Mood, and Fatigue
PQQ improves sleep quality and lessens the time it takes to fall asleep.
One open-label human study conducted with 20 mg of PQQ for 8 weeks in 17 persons with fatigue or sleep-impairing disorder noted that PQQ was able to significantly improve sleep quality, with improvements in sleep duration and quality appearing at the first testing period after 4 weeks. It also led to a decrease in the time it took to fall asleep, but required 8 weeks to reach significance.
This study also noted improved appetite, obsession, and pain ratings that may have been secondary to improved sleep; contentedness with life trended toward significance over 8 weeks, but results were inconclusive [R].
While this study was done in people with sleep problems, I’ve had similar benefits without sleep issues and others have reported similar subjective experiences.
PQQ Decreases Insulin Resistance
PQQ alleviates fat-induced insulin resistance by increasing mitochondrial biogenesis in muscle cells, similar to exercise [R]. PQQ also has some pro-oxidant potential by increasing hydrogen peroxide, but by doing this, it can inhibit an enzyme called PTP1B, which increases insulin sensitivity [R, R].
Mice lacking the capability of making this protein showed resistance to obesity and were more insulin sensitive. People with breast cancer have an increased level of this protein [R]. Inhibiting PTP1B also increases the activity of epidermal growth factor.
PQQ Treats Obesity
In rats, a deficiency in PQQ reduced metabolic rate by 10% [R]. Although not studied yet, this could mean that extra PQQ supplementation could increase overall metabolism.
PQQ May Treat Cancer
In one study, PQQ was toxic to certain leukemia cells [R]. PQQ might reduce the formation of melanoma cancers by reducing melanin-producing protein expression (by inhibiting tyrosinase expression and reducing gene activity) [R].
PQQ Improves Immune Health
Depriving mice of dietary PPQ caused abnormal immune function, e.g., dysfunctional immune response to stressors [R, R]. The addition of PQQ to the diet of mice increased levels of CD8+ cells and lymphocytes (important immune regulators) [R].
Is PQQ Safe?
A study found that a week’s consumption of up to 0.3mg/kg PQQ (20 mg for a 70 kg male) is perfectly safe [R]. Extremely high IV doses of PQQ (500 to 1000mg/kg bodyweight) can cause death in rats [R, R].
Side Effects of PQQ
Based on these findings, a no-observed-adverse-effect level of 100mg/kg/day was determined for BioPQQ in rats, the highest dose tested in the 13-week study (R).