While a night out on the booze is often considered an extremely masculine activity, heavy drinking can actually be a man's worst enemy. Jennifer Paterson explores exactly what knocking back more than a few drinks does to the male of the species and his sex drive.

I'm sure most of us are familiar with the term "beer goggles" - the amazing way in which alcohol seems to make the average male see Elle Macpherson in anything with a pair of X chromosomes. The reality, however, is that excessive alcohol consumption often results in a total loss of libido (sex drive).

Not so virile

So what does alcohol do to a man's sex drive? Alcohol lowers the amount of the sex hormone testosterone in the blood. In a male, testosterone is responsible for the regulation, and maintenance, of the sex drive. Alcohol work on the testes in different ways. Directly, it suppresses the testicular cells which make and release testosterone. Indirectly it increases the levels of some hormones that inhibit these cells.

And there's more

Alcohol also interferes with the nerve impulses which allow an erection to occur. Alcohol acts directly on the nervous system, high levels decreasing the conduction of nerve impulses from the brain to the penis. Regular consumption of alcohol at high levels can permanently damage a man's virility - causing inflammation of the nerves and eventually impotence.

And you'll be less fertile

Research has shown that even moderate alcohol consumption can decrease sperm production - leading to reduced fertility. As little as five standard drinks per day can stop sperm developing in its three month life cycle. Moderate alcohol intake may also alter the shape and structure of the sperm, reducing its capacity to fertilise an egg.

What about women?

Ironically enough, alcohol may actually increase a woman's sex drive. Research has shown that even low 'doses' of alcohol quickly increases the level of the sex hormone testosterone in a woman's blood. This increase is most apparent for women on the pill, and during ovulation, and may explain why women often become aroused when drinking socially.

The news isn't all good for women however. Heavy drinking can have detrimental affects on a woman's sexuality, often disrupting or halting her period altogether. Chronic heavy drinkers are more likely to experience a cessation of menstruation, or early 'menopause'. Alcohol seems to keep Oestrogen levels abnormally high, disrupting the menstrual cycle.

Alcohol also seems to increase the risk of spontaneous abortion, as it surpresses progesterone, the hormone that prepares the wall of the womb for a fertilised egg - crucial to a successfully early pregnancy.

What's a 'safe' level then?

As with anything, moderation is the key. The National Health and Medical Research Council of Australia (NHMRC) defines low risk drinking as:

No more than 2 standard drinks per day for women

No more than 4 standard drinks per day for men

At least 2 alcohol free days per week

Date written: September 20, 2000