John Fisher, a 31-year-old mortgage adviser from Salford, Manchester, is not talking about an under-the-counter aphrodisiac. He is describing some of the welcome side effects of his involvement in the British trials of the male contraceptive pill.
The prospect of its widespread availability moved a little closer yesterday with latest results from a worldwide trial showing that a contraceptive injection can be effective in almost 99 per cent of men - a figure as efficient as that of the female pill.
Women around the country, according to experts, can now look forward to a new age of contraceptive equality: one when men are the ones who worry whether they've taken their contraceptives, which will eventually be available in either injection, pill or patch form.
Kirsty, John's wife, is enthusiastic about their time on the 18-month trial. "It was great. I can't take the oral pill, it makes me very poorly and it just came along at the right time," she said. "The injections were weekly. I'm a qualified nurse so it didn't bother me and he got used to them. Definitely his sex drive increased. It wasn't just due to being more relaxed - we'd used other types of contraception." Eighteen months after the trial, was she concerned about the risk of infertility? "No, I'm due to have our first baby this week."
The unlikely prospect of the male pill has raised its head many times before, spawning countless articles doubting its efficacy, under headlines like: "But can he be trusted to take it?"
It has taken 20 years and hundreds of thousands of pounds' worth of research to come anywhere near conquering the prodigious efforts of the male reproductive system, reducing its production of 100 million sperm a day to the paltry 3 million per millilitre required to avoid pregnancy.
Like any form of contraception, it is not infallible. Kevin McQuaide recently became the first man in Britain to father a child while on the contraceptive. He had been on the pill for 18 months and was thought to be "technically infertile".
But according to experts, the results from the latest trials, conducted over two years on 400 couples, are said to be "significant". Yesterday's results show, for the first time, an efficacy of 98.6 per cent, giving it a pregnancy rate of 1.4 per cent- the same as the female pill - without affecting sexual functions or virility.
They also, according to Dr David Griffin, who co-ordinated the World Health Organisation's studies, explode many of the myths that surround the male pill, the two major ones being that the excess testosterone will make men more aggressive or less fertile, and that men are not interested in taking responsibility for the contraceptive process.
The weekly injection (into the buttock), soon to be extended to three- monthly intervals, contains testosterone, which fools the body into believing it has already produced its requisite amount of sperm. "It's like a thermostat, a self-regulating system," he said.
There is little evidence that the testosterone caused increased aggression, "unless you use very high doses. They're very close to normal range anway," he said.
John Fisher said he had noticed a slight increase in aggression, but was able to rationalise it. "That was normally noticeable 24-36 hours after the injection. I normally had it Monday morning and Tuesday night I could be a right nasty little bugger," he said, but added that it was "a small price to pay".
Like John, men who had come off the trials had since fathered "perfectly normal offspring", leading scientists to conclude that hormone levels soon return to normal, as they do in women who come off the pill. And like John, the behavioural changes they have noticed appear to be far less negative.
"This is a common report that their sex life has improved," Dr Griffin said. "How much that is due to the treatment and how much that is a placebo effect because the couples are happier and more relaxed, it's hard to say," he said.
Either way, it has proved a good incentive for men to have the injection. According to Dr Griffin, the trials were heavily oversubscribed, with more than 400 volunteers for the 37 couples monitored by Dr Fred Wu, who headed the most recent trial.
"Whenever we've started a trial we're overwhelmed by men who want to take part," Dr Griffin said. "There is a myth that men are not interested in family planning but I think this is partly down to the fact that the options for men are very limited and not very attractive.
"Men liked the approach [of the injection]. There were some comments that if we had something that didn't require weekly injections it would be much more acceptable. But they were all highly motivated to take part in the study, the majority because the partner had experienced problems," Dr Griffin added.
The latest studies had for the first time incorporated the female partners' views. Perhaps unsurprisingly, there was a "positive reaction". "They did feel that this in many cases improved their relationship because they felt their partner was taking an active role," he said.
Researchers are quick to stress that the male pill is not being touted as a replacement method, or even for exclusive use - rather "just another option to be added to the list". The question of trust, said Dr Griffin, was pertinent, but not to these couples.
He added that many men who were unable to come to the clinic for weekly injections had been given doses for their partners to administer - "and that's the ultimate control for women."
This all bodes well for sexual equality. But the male pill has been largely the result of publicly-funded research, and without the backing of the massive pharmaceutical industry, it is unlikely that it will ever make beyond the laboratory and on to the shelves of the chemist.
According to scientists, there has been a lack of interest in the contraceptive market for some time, largely because in developed countries, where the profits are greatest, it is seen to be saturated. It is also seen as highly risky and potentially litigious, especially in the light of recent scares about the female contraceptive pill.
Of Schering, Wyeth and Roche, traditionally three of the biggest producers of the female pill, only Wyeth has expressed any interest in the male contraceptive market, although it stressed yesterday that its interest was in monitoring, rather than in any funding of large-scale pharmaceutical trials.
Schering says: "It is not an area we are interested in", while Roche recently sold its contraceptive interests altogether. "It was a corporate decision," said a spokeswoman.
According to Marie Stopes, one of the main providers of contraceptive advice, it doesn't matter how efficient and popular the male pill proves in trials if it does not receive the backing of the industry.
"Certainly, if it came on to the market it would be brilliant but I think it's years away. Realistically it won't happen without [the big pharmaceutical companies] unless they have funding and resources to do big trials and marketing," said spokeswoman Sranca Tranza.
She said the fact that so many people volunteered for trials suggested that it could be commercially viable, but added that the potential for litigation was probably even greater than that for women. "It's a real shame and it's a downside of the kind of bad press that contraception has got recently, especially with the pill scare. But it's a very risky business and if men started getting side effects from contraception it would be taken far more seriously than with women," she said.
According to Dr Griffin, the more research that is done, the more interested the pharmaceutical industry may become.
"We do have one or two companies that are interested. They tend to sit back and see whether any problems arise," he said.
And many believe that should the industry take a commercial risk and back what has largely been seen as an alien concept, it may reap rich rewards.
"I think there will be a lot of men who think no way, not for me. But people have become more responsible and I think things are changing, especially with the onset of Aids," said Sranca Tranza. "When people are having stable relationships more choice in the market can only be a good thing. Perhaps a situation will arise where men and women split the responsibility. Women go on the pill for five years and then have a rest while their men have a turn."
John Fisher thinks this may not be such an unlikely scenario. "I'd definitely use it if it became available," he said. "A lot of my mates would, too, now that they know someone who's used it. Quite a few wish they'd had the bottle to give it a go."
It may work, but what's
in it for me?
James, 25, banker
`I'd be prepared to take it, but I can't say I like the idea of having an injection every week - I'd rather it came in another form. I'm not really worried about the drop in sperm count so much as the possible side- effects I've heard about like acne and putting on weight.'
Martin, 24, accountant
`The idea sounds good, but it would be better if it really was a pill. Injections don't bother me, but it's probably all as much of a hassle as a condom. They say lowering the sperm count doesn't affect virility or sex life, but we still don't know very much about it yet. You'd want to make sure it didn't permanently affect sperm production.'
Peter, 33, London Transport worker
`This is one of those things you hear about every so often, and nothing ever seems to happen with it. I think it would be better than using condoms, though, and I wouldn't have a problem with taking it if or when it finally appears. The sperm count issue doesn't really worry me, as long as it was proved there were no other side-effects.'
Tim, 29, technology consultant
`It all sounds good, but the injection would be a bit of a nuisance, and would put a lot of people off. I'm not sure about the idea of interfering with hormone levels, but as long as it didn't make me feel any different then it would be all right.'
Nick, 24, student
`I think I would take it, if I was in a relationship that warranted use of long-term contraception, though I'm not sure about injections. It depends on your personal circumstances. Also there would have to be a guarantee that sperm production would resume on stopping taking it, which is a medical worry rather than one about virility.'
Colin, 29, in marketing
`I suppose I'd have to decide between the pain of the injection and the inconvenience of using a condom. At least once you've had your injection for the week or however long it is you can be a bit more spontaneous. I think the success rate would outweigh any worries you might have about it. Yes, I think I would take it.
INTERVIEWS BY SCOTT HUGHESReuse content