The biochemistry of sex is complex, and much remains to be determined. Discoveries about some aspects of sexual function, however, allow individuals more control of sexual expression and satisfaction. In this column, we discuss a few ways to augment sex experiences.
Areas of the brain involved in sex use the primitive neurotransmitters (substances used by nerve cells to communicate with each other) acetylcholine, dopamine, norepinephrine, and serotonin. When there are inadequate quantities of these neurotransmitters or the nerve-cell receptors are insensitive or too few in number, there can be a decrease in sexual interest and activity.
Depression is usually accompanied by a decline in sexual interest. In several clinical trials, depression often responded to small quantities of the amino acids phenylalanine and tyrosine, which are used by the brain to make both dopamine and norepinephrine. In one clinical trial, about 80 percent of depressions of a wide variety of types were completely alleviated by 100–500 milligrams of phenylalanine a day for two weeks.
Excess phenylalanine can cause irritability, aggression, and insomnia. For best results, take on an empty stomach (some amino acids compete with each other to enter the brain). Tyrosine has also been found effective in similar doses. A word of caution: persons with high blood pressure should use tyrosine or phenylalanine with care because, at high doses, a small percentage of sensitive persons may experience higher blood pressure. Start at a low dose and increase slowly over a period of days to a few weeks, measuring blood pressure frequently while doing so.
Dopaminergic stimulants (substances that activate parts of the brain using dopamine as a neurotransmitter) such as the amino acid prescription drug L-Dopa and the ergot derivative prescription drug bromocriptine frequently cause an increase in libido as a side effect. Medical authorities often consider this a problem in institutionalized patients!
Sometimes, depression may be alleviated by increasing brain supplies of acetylcholine (except in the depression of manic-depressive psychosis, which may be worsened). This may increase sexual activity as well; in our limited clinical experience, nobody under the age of 40 has had this experience, but it is common in people in their 50s and 60s.
Choline, lecithin, and the prescription drug Deaner® (Ricker Laboratories) increase brain acetylcholine. Effective dosages were 3 grams a day of choline or 80 grams a day of lecithin. Vitamin B-5 is required for the conversion to acetylcholine, so a supplement of this vitamin should also be taken for best results. In some clinical trials involving older persons, only a minority benefited, which we think may be due to inadequate availability of vitamin B-5. Too much cholinergic stimulation results in aching or stiff muscles or headache.
The amino acid tryptophan has recently been found to be very effective in alleviating some depressions, especially those involving excessive aggression and sometimes violent suicidal attempts. Tryptophan is converted in the brain to the inhibitory neurotransmitter that decreases nervous activity, serotonin. In some patients given tryptophan, hypersexuality developed. Typical human doses are 1–3 grams taken at bedtime on an empty stomach. Too much tryptophan can cause drowsiness, headache, and stuffy nose.
One of the chemical events leading to orgasm is a release of histamine, a substance with many functions. For example, it is a growth promoter required for healing (it causes that itchy sensation in healing wounds). In people and animals having inadequate histamine release, orgasm may be difficult or even impossible to achieve. Histidine is an amino acid that is converted into histamine in the body. It is found in foods such as meats, dairy products, and some wines. In order for the histidine to be made into histamine, vitamin B-6 is required.
Niacin is of interest because it causes the release of histamine, producing the flushing and itching some people complain of when they take large doses of niacin and the sex flush described by Masters and Johnson. We often take a dose of niacin a half-hour or so before having sex, because it augments the natural histamine release associated with orgasm.
About 20–25 percent of male impotence results from the pituitary gland's excess secretion of the hormone prolactin. Inadequate dopaminergic stimulation, which generally declines with age, is one cause of such excess secretion. The prescription drug bromocriptine (Parlodel®, Sandoz) suppresses prolactin and is very effective in reversing this type of male impotency.
Bromocriptine also increases libido in about 80 percent of those who take it, whether male or female. It has other unusual effects, as well. Some postmenopausal women given bromocriptine for excess prolactin begin menstrual cycling again and are warned to use contraceptives to prevent possible pregnancy at advanced ages. This phenomenon has interested us in the possible use of bromocriptine and related compounds for use against aging clocks (of which menopause is one).
Vasopressin is another pituitary hormone that has several functions, including regulation of urine volume. It is also involved in learning and memory. In a study of men in their 50s and 60s, 16 iu a day (about 8 snorts) of the intranasally administered prescription drug Diapid® (Sandoz), a synthetic version of vasopressin, caused a significant increase in memory and learning, as well as a faster reaction time, and did not have any side effects. (Vasopressin should be avoided by those with angina pectoris, however, because it may initiate an attack.)
We have been using vasopressin for its intelligence-boosting effects for a few years and also found that it prolongs and intensifies orgasms, an effect not mentioned in the scientific literature! It has a short half-life in vivo, less than two hours, and should therefore be used just before sex if it is to have the orgasm-enhancing effect.
A vitamin may be able to increase your sexual stamina. Vitamin B-5 (pantothenic acid or calcium pantothenate) is a part of the co-factor acetyl coenzyme A that is required to produce energy in the body via the Krebs cycle, and also for the manufacture of acetylcholine. B-5 should be taken with choline, lecithin, and, possibly, Deaner®. In one experiment, rats were provided with diets either deficient, adequate, or high in calcium pantothenate. They were then swum to exhaustion in 18 degrees C (64 degrees F) water. Swimming times were:
deficient 16 + ? 3 minutes
adequate 29 + ? 4 minutes
high 62 + ? 12 minutes
Human experiments with cold-water stress are in agreement with these findings.
A reasonable dose of calcium pantothenate (the most stable form of vitamin B-5) is 1–2 grams a day for a healthy adult. Start at a low dose and work up to the 1–2 grams over a period of a few days or so. Vitamin B-5 is a peristaltic stimulant and can be used as a very effective nonirritating laxative.
We have not yet mentioned the classical steroid sex hormones such as the androgens and estrogens. We have written quite a bit on this topic, including instructions for minimal-risk postmenopausal hormone replacement therapy, in our just-published book, Life Extension: a Practical Scientific Approach.
A list of scientific literature on this topic is available through REASON. Send a stamped, self-addressed envelope and ask for H&W references, July.
Durk Pearson and Sandy Shaw are consulting scientists and authors.
This article originally appeared in print under the headline "Health & Welfare: Sex Play".