How Using Lubricants During Sex Can Affect STD Risk

Lubricant gel

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If you're having penetrative sex, whether it's anal sex or vaginal sex, whether it involves fingers, toys, or a penis, sexual lubricants are a good idea. Lubricants reduce the friction when skin slides against the skin.

Even more importantly, if you're practicing safer sex, they reduce the friction when skin slides against latex or polyurethane. That makes repeated penetration less likely to cause microscopic damage, or even tearing, of the vaginal or anal canal, which could increase the risk of STDs.

Lubricants also make safer sex, not to mention unprotected sex, hotter sex. When skin slides slickly against the skin, sex is a lot more fun. Insufficient lubrication can be uncomfortable, or even painful. But with proper lubrication, sex can last longer and be far more satisfying.

Why Lubrication Is Important

Some people worry that, for vaginal penetration, needing to use a lubricant means that the female partner isn't really "into it." However, the body doesn't always respond to the mind and even women who do lubricate well don't necessarily produce enough lubrication for comfort, particularly during sex that involves latex. There's absolutely nothing wrong with including lubricant as part of your foreplay as well as during intercourse. It makes things feel better and it takes a lot of the pressure off the bodies to perform.

For anal sex, a lubricant is an absolute must. The rectum is lined with mucus, but the body doesn't produce nearly enough to protect a thin layer of cells lining the rectum during penetration. Lubrication is particularly needed if people use an enema before sex. Furthermore, if someone does use an enema, they should wait at least an hour before having sex for the rectal mucous barrier to restore itself. Rectal mucus is clear and odorless, and it does a lot to protect the anal canal.

How to Choose a Lubricant

There are a number of factors that should be considered when you are choosing a sexual lubricant. These include:

  1. Will latex or other barrier methods be used with the lubricant?
  2. Where will the lubricant be used? (Penis only, vagina, anus, mouth)
  3. Do the people using the lubricant have any allergies?

Consider Use with Condoms and Barriers

First things first, if you are using latex condoms, dental dams, or other latex barriers, it is important to only use water- or silicone-based lubricants during sex. Look for water as a primary ingredient in water-based products or dimethicone in silicone products.

Oil-based lubricants should never be used with condoms. This includes vegetable oils, baby oil, and Vaseline. Any oil-based product can quickly break down latex, causing a condom to burst. In particular, be careful of using any masturbation cream as a lubricant with a condom. These products are often oil-based.

You shouldn't use oil-based lubricants with condoms for penetrative sex but embrace water- and silicone-based lubricants. A number of studies have shown that proper lubrication significantly decreases condom failure rates, particularly during anal sex.

Consider Where and How the Lubricant Will Be Used

Lubricants can be used for many different types of sex, and thus there are many types of lubricants. Masturbation creams, for male masturbation, are designed only to be used on the skin of the penis, and in general, should not be inserted into the vagina or rectum.

Many lubricants formulated for internal use are formulated to maintain a healthy vaginal pH of around 4. This pH helps to support the normal vaginal flora, and is safe for both vaginal and rectal use, although a rectal lubricant would ideally be formulated at a higher pH -- between 5.5 and 7. What is more of a concern, particularly for lubricants used in anal sex, is a concept called osmolality.

It has become clear that high-osmolality lubricants can cause rectal damage, and possibly vaginal damage, which could increase the rate of STD transmission during intercourse. Osmolality refers to a number of dissolved particles in a solution, such as a lubricant. Since the body tries to equalize osmotic pressure across cell membranes, high osmolality lubricants cause the vaginal or anal linings to push out water to dilute the lubricant, leading to the possibility of cell damage or even death. Such damage is particularly dangerous in the rectum, as it is only lined with a single layer of cells, and damaging these cells provides a very efficient access route for pathogens to get into the bloodstream.

Osmolality is only a concern for water-based lubricants, which may make silicone-based lubricants a better option for anal use. However, if you prefer water-based lubricants, look for ones with low concentrations of glycerol and propylene glycol. These compounds increase osmolality and should be less than 8-9% of the mass of the product. 

Ingredients You May Want to Avoid

There are a number of ingredients in lubricants that you may want to avoid for internal use because they have the potential to increase STD risk through skin reactions or other problems. These include

  • Nonoxynol-9 - which can serve as an irritant
  • Glycerols and glycols, which increase osmolality
  • Petroleum-based oils
  • Polyquaternium compounds, some of which (particularly polyquaternium-15) may increase the risk of HIV through enhancing viral replication

Fragrances, numbing agents, and preservatives can also be allergenic or irritants for some people. Therefore, lubricant experts recommend looking for products with the shortest ingredient lists possible, particularly for those with sensitive skin or contact allergies. This may be particularly a concern when choosing a water-based lubricant, as more variety is available, and therefore there is a larger range of potentially problematic ingredients.

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Article Sources

  • Mueller, S (2015) "Lube! An In-depth Look at Personal Lubricants." Sex Education Networking and Community Building Conference
  • World Health Organization (2012) "Use and procurement of additional lubricants with male and female condoms: WHO/UNFPA/FHI360 - Advisory Note." WHO/RHR/12.33