We humans like the idea of spontaneity in our romantic relationships, we look for drugs and other agents that may help stimulate sexual desire, but love is a rebel bird that nobody can ever tame and lust is a fickle mistress not well understood.

We have seen considerable interest in using chemical communication based on human pheromones to help stimulate sexual desire, just like the gipsy moth. The idea is that every bead of sweat that evaporates from the skin creates invisible chemical messages of a sexual nature in the air behind us.

Androstadiene is one of the pheromones released in male sweat and may be the closest thing to a natural aphrodisiac, this happens to transmit from male to female, yes well not really the sweet fragrance that Afrodite brings to mind!

Nevertheless, it has an affect but not in the carnal sense, the result in humans is not the same as in the gipsy moth. In humans the compound affects the vomeral nasal organ (two small cavities located either side of the nasal bridge) that in turn stimulates pleasure centres (ie the hypothalamus and the limbic systems) in the brain, these are basically the seat of human emotions.

However the results are not consciously felt ie the subject has no feeling of arousal or attraction, so not the archetypal response we would expect from a true "aphrodisiac". The affect is more relaxing; it makes you feel more positive.

Typically the subject simply becomes more "friendly" and communicative, there is a sensuous feeling but you would not necessarily even be aware of the fact that you are having an uncharacteristically positive "reaction" to someone. Nevertheless, under the correct conditions this can be enough to get things going as it were.

There is now a sizeable industry built around pheromones, again these are not direct aphrodisiacs, they simply create a reduction in negativity but that said I can't ignore the potential here in the preparation for sexual behaviour, this could easily be part of the natural process or the message may not be remotely sexual.

It is worth noting that pheromones are not a new discovery, the affect was known to some of the ancient cultures; for example "white magic" used in Brazil is just coffee made using soiled undergarments as a filter, this is based on the idea of pheromones, and may well have had some impact, maybe :-)

Pheromones are clearly not the complete answer, but that doesn't mean the source of passion can't be bottled or soled, yet!

When we fall in love, we suffer from uncharacteristic changes in behaviour resulting from an overdose of dopamine and norepinephrine, which are naturally produced stimulants. Here we have a semi-aphrodisiac in the form of a chemical cocktail found in the brain.

The result is that we can feel elated one minute but then very depressed because of a dramatic change in the levels of these neurotransmitters, which indirectly affects our higher reasoning and emotional responses.

More dopamine and norepinephrine changes the association between romantic love and sex, the feelings of warmth and intimacy are triggered by serotonin which is a relaxant, this explains romantic infatuation ie obsessive love, but again this is not a recipe for love!

We may well understand the chemistry of romantic love but we cannot use this as an aphrodisiac. That is we can not direct the feelings one way or another, the human brain is just too complex!

Testosterone is the sex hormone, and this is the one true aphrodisiac in male and female biology, it is responsible for desire and directly affects the lebedo.

Testosterone has the affect of increasing cravings for sexual gratification; the number and intensity of sexual fantasies and in fact can also help create better sex overall!

I'm not implying we should go around secretly slipping testosterone additives into our lovers' drinks, mainly because excessive amounts can result in aggressive, irritable behaviour and it typically takes about 36 hours before the results are felt.

This will only work as an aid to a preexisting relationship but it will never make someone fall in love with you.

However if all you want is just the illusion of love, than you would be better-off attempting to achieve an advanced state of mental incompetence by the repeated consumption of fermented vegetable drinks instead!

I am the website administrator of the Wandle industrial museum (http://www.wandle.org). Established in 1983 by local people determined to ensure that the history of the valley was no longer neglected but enhanced awareness its heritage for the use and benefits of the community.