Personal Lubrication – What You Don’t Know About Osmolarity May Be Hurting You

Osmolarity is more than a difficult word to say quickly, three times in a row.

A chemist or a biologist would probably define osmolarity as a measurement of the total amount of chemicals dissolved in a liquid, cream, lotion or gel. Stated in a slightly different manner, osmolarity is the overall component concentration of a liquid.

Osmolarity occurs to help produce an equilibrium, when a substance in a solution (such as a fluid) crosses a membrane from an area of lower concentration to an area of higher concentration. As well, osmolarity is sometimes also referred to as osmolality. Solutions containing the same concentration of particles are said to be iso-osmotic or (isotonic).

The medical community must be aware of the osmolarity of a wide range of fluids, because for example, putting fluids into the blood that are not isotonic with blood may have profoundly negative impact. Whereas fluids that are isotonic or iso-osmotic with blood, may enter the body and remain there in harmony.

Blood osmolarity is normally between 275 to 295, urine can range from 50 to 1200, but after 12 to 14 hour fluid restriction this number should be over 850, while normal saline solution (often put into the body) has an osmolarity of 286.

In addition to this small list, the normal osmolarity of the following items, should also be noted:

  • Female vaginal secretions (a woman’s natural lubrication): 260 to 290
  • Human semen: 250-380
  • Coconut Oil: 180-340
  • Most commercial personal lubricants: 1,000 to over 10,000 (1)

As you may have noticed, the osmolarity of coconut oil is in the same range as the osmolarity of many core elements of the human body (the blood, vaginal secretions and sperm, for example). Therefore, these items are all iso-osmotic and may therefore be expected to exist in harmony. Stated slightly differently, they all contain the same concentration of dissolved particles permitting them to exist happily together in a cheerful state of equilibrium.

In comparison and nestled unhappily, in a dark place far away from the sunny bliss of coconut oil and body fluids, you will find the land of the personal lubricants. As noted by the short list above, the osmolarity of most commercial lubricants is much higher. But, what does this mean?

When two fluids combine that have a similar osmolarity, as mentioned, they create an equilibrium. Because of this equilibrium, the two fluids can peacefully co-exist. For example, coconut oil can be expected to play quite nicely with the human body, because the natural range for the osmolarity of coconut oil (180-340) is quite close to the osmolarity of vaginal secretions and sperm (260-380).

However, when two fluids combine that do not have the same osmolarity, they combine and then try to create a balance. Unfortunately, in an effort to form this new equilibrium, damage is caused by movement in or out of endothelial cells. And, the bigger the difference is between osmolarities, the greater the chance is for cellular damage and the faster that damage should be expected to occur. In fact, some research has already shown that personal lubricants can damage the cell lining of the vagina and the rectum. One such study, a January 2012 study published by the U.S. National Library of Medicine and the National Institute of Health, concluded that “lubricant products may increase vulnerability to STI’s (sexually transmitted diseases). Because of wide use of lubricants and their potential as carrier vehicles for microbes.” Additionally, when the protective lining of the rectum or the vagina becomes damaged, one of the body’s normal defense mechanisms is weakened. (2)

In addition to this study, one other study also seems quite significant in its ability to document the impact of the osmolarity of personal lubricants. This study was published by the World Health Organization (WHO) in 2012. It was titled “Use and Procurement of Additional Lubricants for Male and Female Condoms”. (3)

According to this study:

  • Several papers (13-16) suggest that lubricants with high osmolality might cause vaginal and anal epithelial damage. Confirmation that lubricants with high osmolality can cause epithelium damage when applied rectally to humans has been demonstrated in a group of 10 volunteers.
  • Epithelial damage could in turn increase the risk of infection, for example by HIV and other sexually transmitted infections (STIs), particularly when condom use is inconsistent.
  • Most commercial personal lubricants have high osmolalities (2000-6000 mOsm/kg). This study reviewed over 40 personal lubricants.
  • Ideally, the osmolality of a personal lubricant should not exceed 380 mOsm/Kg to minimize any risk of epithelial damage.
  • Do not use oils (or coconut oil) with latex condoms, because they “have a highly damaging effect on latex.”

In summary, Osmolarity is important for the following, simple-to-understand reason:

  • High Osmolarity = High Risk for STIs (sexually transmitted infections)
  • Low Osmolarity = Low Risk for STIs

It should also be noted that the components that increase the osmolarity of coconut oil are dramatically different than the ingredients that increase the osmolarity of most commercial personal lubricants.

Conventional, non-organic lubricants contain ingredients like chlorhexidine, petrochemicals, parabens, silicon, glycerin, propylene and artificial fragrances, dyes or flavorings.

In 2002, during a Phase II/III clinical trial, even the highly touted nonoxynol-9 came face-to-face with the cold, hard truth that in addition to being a powerful spermacide, it also damages the cell lining of the vagina and rectum, thus increasing the risk of HIV infection in the people tested. And yet, nonoxynol-9 is still used on condoms today. (4)

Comparatively, coconut oil osmolarity is increased by the presence of natural constituents like amino acids, enzymes, minerals, and fatty acids which combine to create a pure, well-balanced source of healthy and hydrating nutrients.


(1) “Studies Raise Questions About Safety Of Personal Lubricants” by Lauren K. Wolfe of Chemical & Engineering News: Volume 90, Issue 50, pp. 46-47 (link to complete article, listed below).
(2) “The slippery slope: Lubricant Use and Rectal Sexually Transmitted Infections: a newly identified risk”. Sex Transm Dis. 2012 Jan;39(1):59-64. doi: 10.1097/OLQ.0b013e318235502b. PMID: 22183849.
(3) “Use and procurement of additional lubricants for male and female condoms: WHO/UNFPA/FHI360 – Advisory Note” by the World Health Organization in 2012 (link to complete article, listed below).
(4) “Effectiveness of COL-1492, a nonoxynol-9 vaginal gel, on HIV-1 transmission in female sex workers: a randomised controlled trial” (Lancet, DOI: 10.1016/s0140-6736(02)11079-8).