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D-Aspartic Acid or DAA

Increasing testosterone naturally

D-Aspartic Acid

A naturaly occurring amino acid

Aspartic Acid - An acidic amino acid

  • The L-Aspartic Acid amino acid isomer is a proteinogenic amino acid i.e. it is used along with the 20 other amino acids to form proteins in the body.
  • Along with glutamic acid, aspartic acid is classified as an acidic amino acid.
  • It is not an essential amino acid and is found in animal meats, vegetables and sweeteners such as young sugar cane and molasses and is the basis of artificial sweeteners such as Nutrasweet® or Equal®.
  • The function of the D-isomer of Aspartic Acid or D-Aspartic Acid (DAA) was less known until recently.

D-Aspartic Acid (DAA) and Testosterone Production

  • D-Aspartic Acid is found in many tissues but importantly, it is found in the pituitary gland and in the Leydig cells of the testes where testosterone is produced as a result of stimulation by pituitary Leutinizing Hormone (LH). The production of  LH is also stimulated by DAA50.
  • The other exciting fact is that DAA in the pituitary also stimulates the production of growth hormone (GH)50.
  • Both testosterone and growth hormone slowly decline as men age.
  • D-Aspartic Acid works by increasing a regulatory protein called steroidogenic acute regulatory (StAR) protein, a critical transport protein that regulates the transfer of cholesterol into mitochondria used in the production of testosterone51.
  • It is important to note that cholesterol is the starting point for all steroid hormones and for cholesterol to be converted to steroid hormones it needs to be transferred from the outer mitochondrial membrane to the inner mitochondrial membrane where an enzyme called cytochrome P450scc  cleaves the cholesterol side chain to begin the process of steroid hormone creation. It is now known that the principal inter-membrane mitochondrial cholesterol transport protein is StAR protein.
  • StAR promotes the transfer of cholesterol into mitochondria where it is converted to the "mother" of all hormones pregnenolone.
  • To see where StAR acts in the conversion of cholesterol to hormones please view the NutriDesk Flash tutorial: Steroidogenesis
  • 20 out of 23 subjects aged 27 - 37 years of age, treated with D-Aspartic Acid had a 42% increase in testosterone levels and a 33% increase in LH50.
  • This is quite an amazing finding that a natural substance like DAA can increase testosterone levels in normal healthy men with already normal testosterone levels.
  • The dose used in the study was 3 grams50.

Testosterone being converted to 17ß Estradiol

  • In animal studies (boar, lizard), D-Aspartic Acid was shown to increase gonadal (testes, ovary) aromatase activity which is an enzyme responsible for the  conversion of  testosterone to 17ß Estradiol (an estrogen).
  • Whether this aromatase activity is increased in humans is uncertain. However, in Western obesogenic societies where abdominal fat is a major concern in countless millions of individuals, we know this deep visceral fat is very active tissue and we also know this active fatty tissue has significant aromatase activity.
  • Increased testosterone levels induced in overweight individuals by D-Aspartic Acid, will indeed drive the conversion of testosterone to estrogen in this abdominal fat store thus increasing 17ß Estradiol.

The use of Chrysin a natural flavone to block aromatase?

  • Chrysin is a naturally occurring flavone that is produced by chemical extraction from the blue passion flower (Passiflora caerulea).
  • It has long been used in supplements and included in hormone preparations by compounding pharmacists as a natural aromatase inhibitor.
  • It is tempting to think that Chrysin in addition to D-Aspartic Acid will negate the possible conversion of testosterone to estrogen by suppressing aromatase activity.
  • Many studies however, have shown little if any in vivo suppression of aromatase activity. This may be due to Chrysin's low bioavailability when taken orally. However, the addition of piperine to Chrysin can increase chrysin's bioavailability significantly.
  • Flavonoids like chrysin have also been shown to suppress thyroid activity by inhibiting deiodinase activity and preventing the conversion of T4 to T353. This may be a problem in individuals who may be suffering from incipient (early) hypothyroidism.

So how can we use D-Aspartic Acid's important testosterone stimulating effect without the estrogen effect?

  • Pharmaceutical aromatase inhibitors are available but will require a prescription and supervision by a doctor. These are also very expensive.
  • Two naturally occurring compounds found in cruciferous vegetables  such as broccoli and broccoi sprouts, kale, watercress, collard greens and called dietary indoles are Indole-3-Carbinol (I3C) and diindolylmethane (DIM), both these compounds cause the body to shift metabolism of estrogen via the 2-hydroxylation pathway to safer, less estrogenic compounds for excretion.
  • Many studies have been done and shown relative safety of these compounds in human studies and showing the benefit of these compounds in protecting against glandular tumours (breast, prostate)55,56.
  • Just 400 mg to 500 mg per day of indole-3-carbinol, can significantly shift conversion of the more powerful estrogen forms to weaker metabolites through the cytochrome P450 system. You can explore the important effects of dietary indoles by following this link: Glucosinolates
  • Many researchers believe that the use of indoles in the diet are a powerful chemopreventative strategy to prevent (or modify) estrogen dependent tumours55,56.
  • Ginger is also thought to help increase the production of testosterone and has been shown to have androgenic activity. In fact, an animal study showed not only increased testosterone production but increased testicular weight57.
  • Red wine, non-alcoholic red wine, green tea and black tea can significantly decrease aromatase activity58.
  • Quercetin and Resveratrol have potent inhibitory effects on Estrogen Sulfotransferase (EST)59 the sole sulfotransferase expressed in human breast epithelial cells. It is the EST that determines the free estrogen level in breast tissue. The addition of Quercetin and Resveratrol to the use of D-Aspartic Acid may be prudent to decrease the tissue effects of possible increased estrogen production through the conversion of the increased testosterone levels brought about by D-Aspartic Acid.
  • The Norway spruce plant lignan hydroxymatairesinol (HMR), is metabolized to “enterolactone” in the gastrointestinal tract and then absorbed into the bloodstream. Enterolactone can work through various mechanisms to antagonize the effects of estrogen and enterolactone can also block the action of aromatase60,61.
  • Lignans from Flaxseed meal is also converted to enterolactone and enterodiol in the gastrointestinal tract. A NutriDesk tutorial shows how lignans can be of enormous benefit in protecting the breasts and prostate against cancerous change. Click on this link: Lignans

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