Alpha-GPC gave man (79) uncontrollable libido
Neurologists sometimes use supplements containing L-alpha glycerylphosphorylcholine – Alpha-GPC for short – to treat early and mild forms of dementia or Alzheimer's. One side effect that these supplements can have is an unhealthily large increase in libido, write neurologists at the Italian IRCCS Centro Neurolesi Bonino-Pulejo in the Archives of Sexual Behavior.
Alpha-GPC, the supplement referred to in the Italians' publication, is also called choline-alfoscerate. Its structural formula is shown here.
When taken in doses of 400 to 1200 mg alpha-GPC can reduce forgetfulness. [Clin Ther. 2003 Jan;25(1):178-93.]
That was also the reason why a 79-year-old man approached the authors of the article. He was the picture of health, his testosterone level was normal, but his short-term memory was declining. This is why the doctors prescribed alpha-GPC for the man.
After using the supplement for six weeks the man's sexual behaviour had changed. Before supplementation he had sex about once a month, after taking the supplement he wanted sex several times a day. He also asked his wife to perform oral sex, something he had never done before. In addition he wanted sex in unusual places, and had started to masturbate 'to alleviate his psychological discomfort'.
Both the man himself and his wife also reported that alpha-GPC made his erection harder.
When the researchers got the man to stop taking the supplement his sexual drive decreased within five days.
After that the man started taking the product secretly for a month, during which time the hypersexuality returned.
The researchers speculate that alpha-GPC converts into the neurotransmitter acetylcholine in the body, and that this boosts the blood supply to the genitals.
Another mechanism that may be at work is that alpha-GPC converts into trimethylglycine. Trimethylglycine contributes by donating methyl in the synthesis of pro-sexual neurotransmitters and hormones.
The Italian case study is novel: it is the first report of hypersexuality as a result of taking alpha-GPC. There is extensive literature on hypersexuality caused by dopaminergic substances.
"As hypersexuality may be an underreported and overlooked adverse effect of drugs and dietary supplements acting on the cholinergic and aminergic pathways in predisposed individuals, this should be considered when treating and counseling older patients with inappropriate sexual behaviors", the researchers conclude.
Arch Sex Behav. 2014 Jan;43(1):187-9.
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