Lubricants may increase disease risk of anal sex, studies show

The use of lubricants may make anal sex more comfortable, but they may also increase the risk of spreading sexually transmitted infections, including HIV, researchers said Tuesday. Many experts have been concerned about the potential effects of such lubricants, but there have previously been virtually no studies about how they affect disease.

In the United States, as many as 90% of gay men practice anal sex, according to International Rectal Microbicides Advocates, a group that has been lobbying for the development of microbicides — chemical agents that can kill HIV during sexual acts. Estimates in the U.S. also suggest that as many as 35% of women have participated in anal sex at least once. The majority of both sexes are thought to use lubricants to ease penetration.
Epidemiologist Pamina H. Gorbach of UCLA's Geffen School of Medicine and her colleagues studied 879 men and women between October 2006 and December 2008. The participants were tested for gonorrhea and chlamydia and queried about their sexual behavior in private, computer-based interviews, which have been shown to elicit more truthful answers than face-to-face interviews. Of the 879 participants, 229 men and 192 women reported having receptive anal intercourse in the past year, and about half said they used lubricants. When the team analyzed the data, Gorbach told a Pittsburgh microbicides meeting, they found that those who used lubricants were three times as likely to have contracted a rectal infection.

A partial explanation for the increased risk may have been provided by Charlene Dezzutti, a reproductive science specialist at the University of Pittsburgh, and her colleagues. They studied the effects of six of the most popular lubricants on rectal cells and tissues in laboratory dishes.They found that many of the products had high concentrations of dissolved salts and sugars that draw water out of cells, weakening and even killing the cells. Some of them even stripped away significant portions of the surface epithelial cells on the rectal tissue, the layer of cells that serves as a protective barrier. They also studied the effect of the lubricants on beneficial bacteria in the rectum.

Two of the six lubricants, PRE and Wet Platinum, were shown to be safest for the cells, while Astroglide was the most toxic to cells and tissue. KY Jelly had the worst effect on rectal bacteria, essentially wiping out the entire colony. ID Glide and Elbow Grease had intermediate effects, the team found. None of the lubricants was found to have measurable anti-HIV activity.

The team now plans to investigate the effect of the lubricants on HIV infections.
- Thomas H. Maugh II


Written by Dr John Dean, specialist in sexual medicine, and Dr David Delvin, GP and family planning specialist

What is it?

Anal sex means sexual activity involving the bottom – in particular, the type of intercourse in which the penis goes into the anus. It is often referred to as ‘rectal sex'. Anal sex does carry some health risks, so please read our advice carefully.

Our impression is that anal sex has become rather more common in heterosexual couples, partly because they have watched ‘blue movies’ in which this activity so often occurs.

One small study carried out in 2009 suggested that 30 per cent of pornographic DVDs which are on sale in the UK feature rectal intercourse. Often, it is presented as something that is both routine and painless for women. In real life, this is not the case.

Other types of sexual activity which involve the anus include:

‘postillionage’ – which means putting a finger into the partner’s bottom.

insertion of ‘butt plugs’ – which are sex toys that dilate the anal opening and create a sensation of fullness.

use of vibrators on or in the anus (please see cautionary note below).

'rimming’ – which is oral-anal contact; this carries a significant risk of infection.

‘fisting’ – which means putting the hand into the rectum; this activity is rare among heterosexual couples.

Taboos and infection

There are taboos surrounding the various types of anal sex – and particularly anal intercourse. These may arouse strong feelings of moral indignation, guilt and anxiety.

It is important to remember that while some people find these activities repugnant, others may find them stimulating, exciting, and a normal part of their sexual intimacy.

Research shows that, whether we like it or not, the anal area is equipped with many erotic nerve endings – in both men and women. So it is not surprising that many couples (including a lot of heterosexual ones) derive pleasure from some form of ‘bottom stimulation'.

What about infection? Most sexual activities carry a risk of transmission of sexually transmitted diseases (STDs) from gonorrhoea and herpes to hepatitis B and HIV. There is evidence that anal intercourse carries a higher transmission risk than almost any other sexual activity. Information about these risks is given below.


What consenting adults enjoy sexually in the privacy of their homes is their own business provided that the law does not prohibit it.

The key issues are legality and consent. In the UK, anal intercourse is a legal activity between consenting men and women aged 16 and over, in both heterosexual and homosexual relationships, except in Northern Ireland where it's 17 and over.

In some countries it is still a criminal offence punishable by long custodial sentences, corporal or even capital punishment. It remains forbidden in some states of the USA, and in some former colonies of Britain.

Consent freely given by both partners is an essential feature of sexual activity in a loving relationship. Many individuals, both men and women, may have secret fantasies involving anal intercourse but feel unable to discuss them with their partner.

Some may try and pressurise their partner to have anal intercourse, even though the partner does not share their interest. Some partners will reluctantly acquiesce, others may be pressured or even physically forced to allow it.

Forcing or pressurising a partner to submit to an activity that they find distasteful or degrading is completely unacceptable behaviour.

Intoxication with drugs or alcohol is associated with lowering inhibitions and experimentation with unusual or unsafe sexual behaviour – and can lead to serious consequences.

It should be remembered that in the absence of freely given consent, the very serious criminal offences of assault and rape are committed. Therefore, it is essential that both partners agree that they wish to try anal sex as a part of their sexual repertoire and that they are sure of the legal position on anal intercourse in the country that they are in.

Who does it?

There is a common misconception that anal sex is practised almost exclusively by gay men. This is certainly not the case. An estimated one third of gay couples do not include anal intercourse in their lovemaking. About one third of heterosexual couples try it from time to time.

It is thought that about 10 per cent of heterosexual couples have anal intercourse as a more regular feature of their lovemaking. In absolute numbers, more heterosexual couples have anal sex than homosexual couples, because more people are heterosexual.

Is it safe?

Anal sex, if practised with care, is possible for most couples. It does, however, carry additional health risks and there are safer sexual practices that couples can enjoy. The main health risks, which affect both heterosexual and homosexual couples, are described below.

Human immunodeficiency virus (HIV): there is no doubt that anal intercourse carries a greater risk of transmission of HIV - the virus that can cause acquired immunodeficiency syndrome (AIDS) - than other sexual activities, particularly for the receptive partner.

Human papilloma virus (HPV, wart virus): this can be transmitted during anal intercourse and lead to anal warts, which in turn could perhaps predispose infected individuals to cancer of the anal canal.

Hepatitis A (infectious hepatitis): this is a viral infection that can cause jaundice and abdominal pain. Hepatitis A is not usually a life-threatening illness, although sufferers can feel quite ill. It can be transmitted by oral-anal contact.

Hepatitis C: is a cause of progressive and sometimes fatal chronic liver disease. Hepatitis C may be transmitted by anal intercourse, although this seems to be a rare occurrence. Sharing of equipment for intravenous drug use is a far more important risk for transmission.

Escherichia coli (E. coli): may sometimes cause mild to severe, or even (rarely) fatal, gastroenteritis. It is one of many viruses and bacteria that can be transmitted by oral-anal contact. Some E. coli strains (uropathic E. coli) can also cause urinary tract infections (UTIs), ranging from cystitis to pyelonephritis - a serious kidney infection. E. coli very readily crosses the short distance between the female anus and the female urinary opening, so causing a urinary infection. Anal intercourse can facilitate this ‘transfer’ – particularly if it is immediately followed by vaginal intercourse.


Avoiding anal sex altogether is of course the best way of avoiding these risks. There are other, safer sexual practices that can be exciting and rewarding, but many couples may still wish to try the anal route.

The use of condoms and water-based lubricants, such as K-Y Jelly, will offer some protection. Other lubricants may cause condoms to split, as will over-energetic thrusting without adequate lubrication. Specially toughened condoms designed for anal intercourse may offer more protection.

How to have anal intercourse safely

Anal intercourse involves the penetration of the anus and rectum with the erect penis for the purpose of sexual stimulation. It is possible for both men and women to ‘receive’ it, although care is needed for it to be safe and comfortable.

Ensure the anal area is clean and the bowel is empty. This is important both aesthetically and practically. If the bowel is empty, there is no risk of the receptive partner passing faeces.

The 'receptive' partner must be able to relax the anal sphincter in order to accommodate the erect penis. The anal sphincter is a ring of muscle that can be contracted or relaxed under voluntary control. Forced penetration may result in tearing of the sensitive skin around the anus or the sphincter itself. This may result in severe anal pain or even faecal incontinence.

Try gently inserting a lubricated finger, perhaps covered by a condom or glove into the anus first. This will enable the receiving partner to find out whether penetration is comfortable and enjoyable. Having managed to accommodate one finger, you can run the finger around the anal canal - gently stretching it. This must be done delicately so as not to cause pain or injury.

Next, you can, if you wish, try and insert two fingers. If this is successfully achieved, the couple may agree to try with a well-lubricated penis or with a butt plug (a broad-based anal dilator), dildo or vibrator (see below about the risks of sex aids and anal sex).

Gentleness, care, adequate lubrication and anal relaxation are required, not the insertive partner pushing harder! If condoms are used for penile penetration, which is advisable to reduce the risk of sexually transmitted disease, it is important to use a water-based lubricant. The insertive partner must control any thrusting, so as to give the receptive partner time to allow the sphincter to relax. With time and practice, this may become easier.

Drugs and anal sex

Muscle relaxant drugs (amyl nitrate, butyl nitrate, glyceryl trinitrate) have been tried to make anal intercourse easier or more comfortable. We do not recommend this. Amyl nitrate 'poppers' sold in small bottles for inhalation, are popular in the gay community and have a reputation both for enhancing the intensity of orgasm and helping relax the anal sphincter. There is no real evidence to support these assertions and its use is not recommended by medical authorities. It is important to remember that amyl nitrate is a potent drug with many side effects, including facial flushing, headaches, dizziness and low blood pressure, which may lead to faintness and loss of consciousness. Amyl nitrate, when taken with Viagra (sildenafil), may cause a catastrophic drop in blood pressure with potentially fatal consequences. Other nitrates may have the same effect. All erection-inducing drugs, including Viagra (sildenafil), Cialis (tadalafil)and Levitra tablets (vardenafil), can be very dangerous if you are using nitrates.

Local anaesthetics, such as lignocaine (lidocaine) cream or even locally applied cocaine, have been used to reduce anal pain during intercourse. Again, we strongly advise against this. By numbing the anal skin there is a real risk of causing serious injury to the anal sphincter through over-vigorous thrusting. By following the steps above it is possible to gently dilate the sphincter for comfortable intercourse. The purpose of pain is to make us aware that we are causing injury and, therefore, local anaesthetics should be avoided. Another problem with local anaesthetics is that they may make the penis of the insertive partner numb. This may lead to problems with erection, orgasm and ejaculation.


This involves the insertion of the whole hand or forearm into the anus (or indeed the vagina) for sexual stimulation. With adequate relaxation it is physically possible and may be acceptable and enjoyable for some couples. But the diameter of the hand or forearm is so much greater than that of the penis there is an increased risk of anal injury. For that reason, we do not recommend this practice.

Good anal relaxation in the receptive partner and care by the insertive partner are essential.

In practice, anal fisting is very rarely used by heterosexual couples.


Rimming involves oral contact with the anus for sexual stimulation. This involves a high risk of transmission of infection. So we cannot recommend this practice.

Sex aids and anal sex – a cautionary note

Some couples like to use sex aids for insertion into the anus. Certain individuals may use them for solitary sexual stimulation.

The same principles apply as for genital insertion in that relaxation is essential. Sex aids must be kept clean and washed carefully between use. Condoms may be placed over sex aids as an additional precaution.

One additional risk from the use of sex aids in anal sex is that of losing the aid into the rectum.

Some medical school pathology museums have a wide selection of novel foreign bodies recovered from the rectums of both men and women, ranging from vibrators to milk bottles.

Human ingenuity seems to know no bounds in this area, but it is incredibly foolish to insert potentially breakable objects into the anus and terrible injuries may result.

If you do lose a sex aid into the rectum you should attend the Accident and Emergency department of your local hospital as soon as possible, however embarrassing it may be. The situation will only get worse if it is neglected and the object may break or become more difficult to recover.

In general, you should only use a sex aid which is designed for the anus. Butt plugs and anal vibrators have a broad base which makes it very difficult to ‘lose’ them inside the rectum.

Vaginal vibrators are not designed in this way, and can easily slip inside and buzz their way up the colon. Some have been recovered by surgeons from far inside the abdomen. If they are still vibrating when the patient arrives at the hospital, they produce an interesting but alarming phenomenon called ‘the rotating umbilicus sign'. Don’t let this happen to you.



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