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Pyrroloquinoline quinone

Synonyms: PQQ

What is PQQ?

In the scientific literature, Pyrroloquinoline Quinone (PQQ) is defined as an enzyme cofactor that acts as a growth factor in plants and animals (1). This basically means that PQQ is involved in the activation and expression of cellular factors involved in the regulation of the body's energy metabolism pathways (1). In other words, PQQ plays a role in the remodeling of muscle tissue towards a muscle fiber composition that focuses more on fat burning and less on carbohydrate oxidation (2, 3). As such, PQQ supplementation is of most interest to endurance athletes.

Where does PQQ come from?

PQQ is present in body tissues and body fluids of humans and animals at very low concentrations (i.e. in the nanogram range) (4). Several studies have shown that PQQ is also present in a wide range of foods (2). Studies suggest that humans consume between 0.1 and 1 mg of PQQ (and its derivatives) daily through food.

Benefits of PQQ

Much of the research on the therapeutic properties of PQQ has been carried out in animals, but it is not yet clear how far these benefits can be transferred to humans. However, there are a number of recent human studies that suggest that the benefits observed in animals may also be transferable to humans.

Increased growth rate

Studies conducted with rats and mice show that PQQ, when added to a nutritionally complete diet free of PQQ, as little as 300 µg of PQQ per kilogram of food improves reproduction and increases growth after birth compared to a diet free of PQQ (1).

Antioxidant

The reduced form of PQQ used in supplements has been shown to be a powerful antioxidant that is relatively stable and therefore more effective than other endogenous antioxidants in terms of its effects (1).

Inhibition of inflammation

One of the few human studies has shown that orally supplemented PQQ dramatically reduced C-reactive protein levels (1). C-reactive proteins are one of the most reliable indicators of inflammation. Inflammatory responses are associated with a wide range of chronic diseases, so any nutrient or agent that can reduce inflammation will generally have a positive effect on health.

Fat oxidation

Animal and human studies show that PQQ has the potential to promote a process known as beta-oxidation, which is the body's primary pathway for producing energy from fat (5, 6). This is the area where PQQ could potentially improve performance in athletes.

Anabolic effects

Animal and human studies suggest that supplementation with PQQ may increase nitrogen retention in muscle and thus have anabolic properties with respect to muscle growth (1, 7).

Safety and side effects

There are no formal safety data on PQQ in humans, but given the low levels found in food and the relatively high cost, the potential for consuming high levels is likely to be limited. In addition, the results of studies conducted in animals do not indicate any potential side effects from the consumption of PQQ.

Recommended intake and timing of intake

Human studies have used between 0.2 to 0.3 mg PQQ per kilogram of body weight, which corresponds to about 14 to 21 mg PQQ for a 70 kilogram person. Although the timing of intake is not critical, many recommend taking it in the morning due to the presumed positive effects on brain function.

Supplements

At the time this article was written, there were very few PQQ supplements available on the market. The products available to date typically provide between 5 and 15mg of PQQ per serving. Some of these supplements are available in liquid form, which is believed to have superior absorption, although there is little evidence to support this.

Combinations with other supplements

PQQ is most commonly combined with CoQ10, a popular mitochondrial booster and antioxidant. From its suspected positive effects on neuronal function, PQQ could be combined with other nootropics to complete its effects.

References

  1. Harris CB, et al. Dietary pyrroloquinoline quinine (PQQ) alters indicators of inflammation and mitochondrial-related metabolism in human subjects. Journal of Nutritional Biochemistry. 2013;24:2076-2084.
  2. Kumazawa T, et al. Levels of pyrroloquinoline quinine in various foods. Biochemistry Journal. 1995;307:331-333.
  3. Liang H & Ward WF. PGC-1 alpha: a key regulator of energy metabolism. Adv Physiol Educ. 2006;30:145-151.
  4. Kumazawa T, et al. Failure to verify the presence of pyrroloquinoline quinone (PQQ) in bovine plasma amine oxidase by gas chromatography/mass spectrometry. Arch Biochem Biophys. 1990;283(2):533-536.
  5. Chowanadisai W, et al. Pyrroloquinoline quinone stimulates mitochondrial biogenesis through cAMP response element-binding protein phosphorylation and increased PGC-1alpha expression. J Biol Chem 2010;285:142-52.
  6. Bauerly K, et al. Altering pyrroloquinoline quinone nutritional status modulates mitochondrial, lipid, and energy metabolism in rats. PLoS One 2011;6:e21779.
  7. Adhihetty PJ, et al. The role of PGC-1 alpha on mitochondrial function and apoptotic susceptibility in muscle. Am J Physiol Cell Physiol. 2009;297:C217-25.