Here’s Why You Should Choose 70% Isopropyl Alcohol Over 99% Isopropyl Alcohol

Here’s Why You Should Choose 70% Isopropyl Alcohol Over 99% Isopropyl Alcohol

When you head to the nearest medical store to buy a hand sanitizer, here are the first two things that come to mind:

  1. What brand do you want?
  2. What level of alcohol concentration is optimal for killing microbes?

Each bottle of alcohol-based hand sanitizer gel comes with a label that mentions the alcohol percentage, which is usually above 60%. In this post, we will try and gauge what these labels mean and which concentration you should opt for.


Isopropyl is one of the most common forms of alcohol, and is largely used for disinfecting purposes, especially in the healthcare industry. The alcohol is available in different purity grades. Its effectiveness against germs and viruses depends on how concentrated the solutions are. Two of the most commonly available variants are isopropyl 77% and isopropyl 99%. Both of these variants are used for different purposes, and both are used for cleaning and disinfecting.

Isopropyl 99% is alcohol in its pure form. On the other hand, isopropyl 70% is diluted alcohol. The remaining 30% is purified water that is added to dilute the solution.

Let’s compare the two options:

Isopropyl 70%

As discussed above, isopropyl is diluted and has higher moisture content. This makes it safer to be used on the skin. Most hand sanitizers are also based on 70% alcohol content. The lower alcohol concentration makes it less harsh on the skin.

When it comes to alcohol concentrations, it is commonly assumed that the higher the concentration, the more effective the disinfectant. This is not always true. Higher concentrations don’t always mean higher virucidal properties. The presence of water is also important. The remaining 30% water content plays its part in inhibiting the growth of certain pathogenic microbes by denaturing their cell membranes.

Other than that, water content also slows down inter-cellular evaporation within these microbes. In the case of 99% isopropyl, a lack of water content often causes proteins with their cell membranes to coagulate together. This forms a protective layer around the cell, preventing them from breaking down.

Here’s Why You Should Choose 70% Isopropyl Alcohol Over 99% Isopropyl Alcohol

Higher moisture content also allows the disinfectant to stay on the surface for longer. This helps it kill bugs and microbes longer.


Isopropyl 99% is rarely used for hand sanitizers. It is more an industrial ingredient that’s used as a solvent for various industry-grade products. This variant is commonly used for products that are water-sensitive and need a hydrophobic solvent. Isopropyl 99% is also used for specific laboratory formulations.

Due to its low water content, isopropyl 99% also evaporates quickly. This greatly reduces its shelf life and thus, it isn’t a popular choice for sanitization products.

If you’re looking for 77% isopropyl-based hand sanitizer gels, look no further than Safety 1st PPE. Other than sanitizer gels, the company also stocks nitrile gloves, surgical masks, and personal protective equipment. Shop now.