Summary of Pyruvate
Primary Information, Benefits, Effects, and Important Facts
Pyruvate is a 3-carbon energy intermediate produced in cells from glucose, en route to creating ATP (the main energy currency of working cells). Pyruvate supplementation has been proposed to enhance work output and weight loss by providing more efficient energy that bypasses the ability of the body to store glucose as body fat.
Studies in humans with pyvuate supplementation show promise at high dosages when pyruvate replaces dietary carbohydrates.
Pyruvate has a lacklustre pharmacodynamic profile, and is not well absorbed. Some studies fail to note increases in blood pyruvate or muscle pyruvate in response to supplementation due to its inability to be absorbed and utilized well. Low doses of pyruvate (3-5g) tend to return null results rather than positive results in healthy persons.
Due to its poor absorption, high dose pyruvate is known to cause stomach distress and loose stools in dosages exceeding 15g.
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How to Take
Recommended dosage, active amounts, other details
Most studies on pyruvate substituted dietary carbohydrates for pyruvate as pyruvate itself does contain calories. The dose used in studies showing most fat loss is in the range of 20-50g daily, or replacing 10-20% of caloric intake (initially from carbohydrates) with supplemental pyruvate.
The lowest effective range noted in the aforementioned studies is replacing 6-12g of carbohydrates with pyruvate, but even then the results seen with pyruvate are variable and lacklustre enough to warrant caution in buying this supplement.
In a study using calcium pyruvate capsules, dosages of 7-25g pyruvate equivalence did not influence blood pyruvate levels nor did they influence whole body pyruvate levels. The lack of urinary pyruvate (less than 0.1%) indicated poor bioavailability. The authors hypothesized that either pyruvate is being lost in the feces, or is being decarboxylated in the stomach and intestines, although low fecal loss rates have been noted in humans.
2Interactions with Obesity and Fat mass
Pyruvate is theorized to work via increased the metabolic rate, although a lack of evidence exists for this claim according to one review.
2.2. Human Studies
Multiple studies have been conducted in persons with pyruvate for fat loss, although the most promising studies were done in the early 90s. When energy intake is restricted to 500kcal, weight loss is enhanced (6.5kg rather than 5.6kg) over a period of 21 days with 12g pyruvate. A lesser deficit, 1015kcal, also results in some weight loss, although the degree was lessened to about 0.4kg more than placebo, and very high dosages (22-44g) can induce some fat loss even near caloric maintenance, although the degree is minor (0.7kg versus 0.1kg loss over 6 weeks).
When dosed at 2g per day, pyruvate appears to be ineffective at changing parameter of body mass even in conjunction with an exercise program although it shows trends of fat loss. This may be a dose issue, as 6g pyruvate appears to be statistically significant, with 2.5kg fat loss rather than 1.2kg over a period of 6 weeks in otherwise healthy overweight persons.
3Interactions with Exercise Metabolism
It has been hypothesized that the mechanism is through preserving muscle glycogen by acting directly as a fuel source, and thus prolonging time to glycogen exhaustion.
Studies in humans using large amounts of pyruvate (100g of a Dihydroacetone:Pyruvate mixture in a 3:1 ratio) find increased time to exhaustion in exercises of muscular endurance. This dosage increased blood glucose extraction, which can reduce the rate of perceived exertion.
An oral dose of 7g dose not increased blood levels in trained athletes, nor does it increase performance on aerboic exercise.
One review notes that there do not appear to be any significant adverse effects noted with pyruvate supplementation, but that no long term studies are done in humans at this moment in time.
The most common side effect is gastrointestinal upset, which occurs with higher dosages. One study noted loose stools in 58% of the pyruvate group relative to 28% of the control group, which was significantly different. A pharmacodynamic study using 15-25g noted that all subjected complained of increased gurgling/rumbling (borborygmus) and flatulence.