A personal lubricant (or “lube”) is a liquid or gel that individuals can apply to the vulva, vagina, penis, and/or anus before or during sexual activity to make the area more slippery and facilitate easier penetration.

Using a personal lubricant is perfectly normal, and it can go a long way towards enhancing a sexual experience. In fact, large-scale national studies on the prevalence of lubricant usage have repeatedly shown that people of all gender identities and sexual orientations use lube for sexual activity.

In one study, over 90% of both gay and bisexual male participants reported lifetime lubricant use. Another study that focused on lube use for women in the United States showed that 65.5% of the respondents had used a lubricant at some point in their lives, and 20% had used one in the past 30 days.

People choose to use lube for a number of reasons. The most commonly reported reasons for using a lubricant among the gay and bisexual men of the aforementioned study were to increase comfort during anal intercourse, curiosity, and to make sex more comfortable.

The female participants of the other study cited similar reasons for using lube, including making sex more comfortable, fun, and pleasurable, and decreasing pain/discomfort. (Even though the vagina naturally lubricates itself as a woman becomes aroused, sometimes factors such as aging and hormonal changes result in insufficient lubrication, which can make penetration painful).

Despite its near universal appeal, the properties and composition of personal lubricants can vary greatly from one lube to another. Therefore, a couple should carefully consider which type of lubricant will be best for their purposes because every situation is different.

Consider the following when selecting a personal lubricant:

Type of Lubricant

• Water-based lubricants are generally inexpensive and easy to find. They are safe to use with condoms and silicone sex toys, they do not leave stains, and they wash off easily. However, they may not last as long as other lubricants and may need to be reapplied during sex.
• Silicone-based lubricants are usually longer-lasting than water-based lubes, and they can be good for people with sensitive skin. They are safe to use with condoms and are often considered the preferred lube for anal sex. However, they can deteriorate silicone sex toys.
• Oil-based lubricants are the longest lasting and likely do not need to be reapplied at all during a sexual encounter. However, they should not be used with latex condoms as they increase the risk of ripping or tearing the condom, and they can leave stains on clothing and sheets.

Osmolality

• Osmolality refers to the concentration of particles dissolved in cells or other substances. Substances with a high osmolality have a higher concentration of particles, while substances with a low osmolality are more diluted.
• Personal lubricants have different osmolality levels, and this is important because the vaginal and rectal cells are always striving to maintain an equilibrium of osmolality when a new substance is introduced.
• If a lubricant is hyperosmolar, meaning that it has a higher osmolality than the vaginal/rectal cells, the body’s cells will compensate by releasing moisture and shrinking/shriveling as a result. This scenario is damaging to the vaginal/rectal mucosa, making it more susceptible to irritation and possibly even infection. Some widely available lubricants are hyperosmolar.
• A personal lubricant is considered iso-osmolar if it has the same osmolality level as the cells in body. Iso-osmolar lubricants are preferable because they keep the cells in harmony.
• The World Health Organization (WHO) recommends that individuals use a personal lubricant with an osmolality level below 380 mOsm/kg. However, since most lubricants available worldwide have an osmolality level between 1,000 and 10,000 mOsm/kg, a lubricant with an osmolality of 1,200 mOsm/kg or below is generally accepted.

pH Level

• pH is a measure of how acidic or alkaline an environment is. If the pH level of the vagina or rectum becomes imbalanced, a person may be at higher risk of infection.
• For healthy individuals of reproductive age, a normal vaginal pH level is between 3.8–4.5 and a normal rectal pH level is about 7.
• To avoid creating an imbalance in vaginal or rectal pH, it is a good idea to select a personal lubricant that has a neutral pH, meaning that its pH level is in the same range of that of a healthy vagina or rectum.

Ingredients

• Some personal lubricants contain ingredients that may be harmful to the body. Although research on this topic is limited, early studies indicate that some ingredients in lube could be harmful to the vaginal microbiota and/or toxic to cells.
• Glycols like glycerol/glycerin and propylene glycol are ingredients that are used in products to soften and moisten the skin, including some lubricants. Some studies have demonstrated that personal lubricants that contain glycols may damage the vaginal mucosa. Glycol-containing lubes have been shown to increase the risk of herpes simplex virus 2 (HSV-2) infection in mice.
• Parabens are preservatives that are used in some personal hygiene and cosmetic products. They are also sometimes included in personal lubricants. There is considerable debate about whether or not parabens negatively impact the microflora and cells of the vagina, and further research would be helpful in illuminating the impact of parabens on cells.

Personal lubricants can enhance sexual activity in many ways, making it more enjoyable and, in some cases, less painful. However, it is wise to carefully review the properties and ingredients of a lubricant and/or speak with a health care provider in order to select one that is a good fit for your body and your intended use. 

Resources:

• Dezzutti, C.S., Brown, E.R., Moncla, B., Russo, J., Cost, M., et al. (2012). Is Wetter Better? An Evaluation of Over-the-Counter Personal Lubricants for Safety and Anti-HIV-1 Activity. PLOS ONE, 7(11): e48328. https://doi.org/10.1371/journal.pone.0048328.
  
  
• Dodge, B., Schick, V., Herbenick, D., Reece, M., Sanders, S.A., Fortenberry, J.D. (2014). Frequency, Reasons for, and Perceptions of Lubricant Use among a Nationally Representative Sample of Self‐Identified Gay and Bisexual Men in the United States. The Journal of Sexual Medicine, 11(10), 2396-2405. DOI: https://doi.org/10.1111/jsm.12640.
  
  
• Edwards, D., & Panay, N. (2016). Treating vulvovaginal atrophy/genitourinary syndrome of menopause: how important is vaginal lubricant and moisturizer composition? Climacteric, 19(2), 151-161. DOI: 3109/13697137.2015.1124259.
  
  
• Herbenick, D., Reece, M., Schick, V., Sanders, S.A., Fortenberry, J.D. (2014). Women's Use and Perceptions of Commercial Lubricants: Prevalence and Characteristics in a Nationally Representative Sample of American Adults. The Journal of Sexual Medicine, 11(3), 642-652. DOI: https://doi.org/10.1111/jsm.12427.
  
  
• Wendee, N. (2014). A Question for Women's Health: Chemicals in Feminine Hygiene Products and Personal Lubricants. Environmental Health Perspectives, 122(3). DOI: https://doi.org/10.1289/ehp.122-A70.