Ginko and Prolactin

crowbar46

Active member
Awards
1
  • Established
Animal study: ginkgo is prolactin inhibitor (from ergo-log.com)



Ginkgo biloba supplements decrease the production of the testosterone-inhibiting hormone prolactin in the body, according to Taiwanese researchers in Hormones & Behavior. Ginkgo probably increases the dopamine levels in the brain. Dopamine inhibits the release of prolactin.


The Taiwanese tested male rats, which were given ginkgo daily for four weeks. The researchers used four groups of animals, which were administered zero, 10, 50 or 100 mg of ginkgo per kg body weight per day. During the month the researchers put the male rats together with female rats and recorded the number of times they had sex. The figure on the right shows the number of times the rats had sex during the last day of the test.


Because the researchers wanted to know how ginkgo stimulates the sexual behaviour of rats, they measured the testosterone and prolactin levels. The effect was most clear in the group of animals that had received 50 mg per kg body weight a day.






In high concentrations, prolactin inhibits the production of testosterone. But even when prolactin levels are too low to reduce the production of testosterone, prolactin can still reduce the sex drive. When the researchers examined the brains of the rats in the 50 mg group, they discovered higher concentrations of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid. The Taiwanese researchers think that this is why ginkgo acts as a prolactin inhibitor. They also tested whether ginkgo influences the production of testosterone in the testes directly, but the results were inconclusive.


Ginkgo decreases cortisol levels after stress 16.08.2008
Ginkgo protects elderly against first signs of Alzheimer’s 16.08.2008



Source:
Horm Behav. 2008 Jan;53(1):225-31.
 

crowbar46

Active member
Awards
1
  • Established
Sounds like it could prevent problems with prolactin. For me, at ~275 lbs it would take about 6 g./day. I'll have to check Ginko supplements to see if that's a feasable dose.

Crowbar
 
dsade

dsade

NutraPlanet Fanatic
Awards
4
  • RockStar
  • Legend!
  • Established
  • First Up Vote
Sounds like it could prevent problems with prolactin. For me, at ~275 lbs it would take about 6 g./day. I'll have to check Ginko supplements to see if that's a feasable dose.

Crowbar
Do not take this much ginkgo.

You will notice effects around the 1 gram range, divided into 3 doses.
 

crowbar46

Active member
Awards
1
  • Established
dsade, thanks. Why do you advise against 6 g./day? Is it just because that dosage level is not needed, or is there potential for negative side effects?

The 6 g./day dosage was based on the research study cited above that found the 50 mg./Kg. body weight dose to be the most efficatious (and my weight of ~275 lbs.)

Crowbar
 
dsade

dsade

NutraPlanet Fanatic
Awards
4
  • RockStar
  • Legend!
  • Established
  • First Up Vote
dsade, thanks. Why do you advise against 6 g./day? Is it just because that dosage level is not needed, or is there potential for negative side effects?

The 6 g./day dosage was based on the research study cited above that found the 50 mg./Kg. body weight dose to be the most efficatious (and my weight of ~275 lbs.)

Crowbar
The possibility for side effects is massive at that dose. You also need to convert rat dosage to human dosage...which would be:
It's been a while, but I believe you divide the direct weight conversion by 6-6.5 to account for metabolic differences.
 

crowbar46

Active member
Awards
1
  • Established
dsade, again, MUCH thanks! Now that you mention it, that does sound right; at any rate rat metabolism is overall much higher than human. Wow, thanks for the reminder.

Crowbar
 
dsade

dsade

NutraPlanet Fanatic
Awards
4
  • RockStar
  • Legend!
  • Established
  • First Up Vote
dsade, again, MUCH thanks! Now that you mention it, that does sound right; at any rate rat metabolism is overall much higher than human. Wow, thanks for the reminder.

Crowbar
Looking for the side effects of Gingko overdose right now...yeah, they are bad.

Seizures and extreme blood thinning are the most apparent.

/you owe me a beer
 

Ju1cedUp

Active member
Awards
1
  • Established
i just bought some liquid Ginkgo.. says 1g 1-2 times daily... will 2 times daily have those type of sides?
 
dsade

dsade

NutraPlanet Fanatic
Awards
4
  • RockStar
  • Legend!
  • Established
  • First Up Vote
i just bought some liquid Ginkgo.. says 1g 1-2 times daily... will 2 times daily have those type of sides?
What is it standardized to?
 
dsade

dsade

NutraPlanet Fanatic
Awards
4
  • RockStar
  • Legend!
  • Established
  • First Up Vote

crowbar46

Active member
Awards
1
  • Established
Looking for the side effects of Gingko overdose right now...yeah, they are bad.

Seizures and extreme blood thinning are the most apparent.

/you owe me a beer


If you're ever in Bloomington, In. I'll take you to a kick ass hardcore gym--the Iron Pit--and to the very nearby tit bar for a beer!

Crowbar
 

crowbar46

Active member
Awards
1
  • Established
dsade, what sort of standardization should I be looking for in a Ginko supplement?

THanks,

Crowbar
 
dsade

dsade

NutraPlanet Fanatic
Awards
4
  • RockStar
  • Legend!
  • Established
  • First Up Vote
sethroberts

sethroberts

Active member
Awards
1
  • Established
The possibility for side effects is massive at that dose. You also need to convert rat dosage to human dosage...which would be:
It's been a while, but I believe you divide the direct weight conversion by 6-6.5 to account for metabolic differences.
Dsade is correct, yu have to adjust for body surface area so you need to divide the dose by 5 or 6 for rat studies -- I generally go with 5.
 

crowbar46

Active member
Awards
1
  • Established
OK, another question dsade or Seth, what am I basing the 1 g./day dosage on: the mg. of extract in a product OR the total mg. of ginko leaf the extract is produced from? Now brand ginko--which Nutra carries--is 120 mg. of extract per capsule (at a 50:1 extract ratio). So, I'd need 9 caps/day divided into 3 doses at my bodyweight of ~275 lbs.?

Thanks,

Crowbar
 

crowbar46

Active member
Awards
1
  • Established
Seth Roberts cleared it up: say you weigh 220 lbs.=100Kg.. You take your weight in Kg.=100 x 10 mg. (1/5 the most effective dosage in the rat studies, in order to adjust for rats having a much greater metabolic rate)= 1000 mg. Now if your extract is a 50:1 extract (which the NOW brand is), a 60 mg. cap of extract is produced from 3 g. of Ginko--much more than the 1 g. you need.

In other words seth was saying that one 60 mg. cap/day should be enough to see prolactin inhibiting effects in anyone.

Pop those caps!


Crowbar
 
dsade

dsade

NutraPlanet Fanatic
Awards
4
  • RockStar
  • Legend!
  • Established
  • First Up Vote
Seth Roberts cleared it up: say you weigh 220 lbs.=100Kg.. You take your weight in Kg.=100 x 10 mg. (1/5 the most effective dosage in the rat studies, in order to adjust for rats having a much greater metabolic rate)= 1000 mg. Now if your extract is a 50:1 extract (which the NOW brand is), a 60 mg. cap of extract is produced from 3 g. of Ginko--much more than the 1 g. you need.

In other words seth was saying that one 60 mg. cap/day should be enough to see prolactin inhibiting effects in anyone.

Pop those caps!


Crowbar
did they use whole leaf or extract in the study?
 

crowbar46

Active member
Awards
1
  • Established
It just says Ginko, it never specifies it as an extract.

Seth also thinks (though he said he wasn't sure) that Ginko probably has a short half-life, and thus one would benefit from multiple doses of a lower potency extract: e.g., 20 mg. (at the 24/6% standardization) 3 x day, rather than 60 mg. 1 x day.

Although, as inexpensive as it is I see no reason not to just use 60 mg. 3 x day--that's still within the safety margin to avoid negative side effects. Another person commented that 240 mg. of a standardized extract is generally as high as people go on dosing Ginko.

Crowbar
 
Thread starter Similar threads Forum Replies Date
Nootropics 3
one8seven Supplements 2
Post Cycle Therapy 3
Supplements 20
Supplements 2

Similar threads


Top