Hand sanitizers are water-less preparations, available commercially as gels, rinses and foams. Many are alcohol based (ethanol or isopropanol, additionally n-propanol is available in Europe). Non-alcohol based preparations contain benzalkonium chloride.
Water-less hand sanitizers are not a substitute for adequate hand washing facilities (running water, soap and disposable towels or air dryers). However they are appropriate in situations where such facilities are not available, or inconvenient for frequent use. Bottles of hand sanitizer are convenient and quick to use. However, when there is visible dirt on hands, the dirt must be removed by washing with soap and water.
The US Centers for Disease Control and Prevention advises “Alcohol solutions containing 60%–95% alcohol are most effective”. Some commercially available preparations available contain less than this amount.
Follow the manufacturer’s instructions for use. The amount to use varies on the type of preparation used. Approximately a palmful (about 2 to 3 ml) of a gel preparation is adequate to cover all surfaces of hands and fingers. Rub the product over the hands and fingers for about 20 to 30 seconds until dry. If hands are dry in a shorter time, it is possible not enough products have been used.
Possible problems with use of hand sanitizers are drying, stinging and irritation of the skin. Generally the products that contain skin conditioning agents are better tolerated. Any abrasions or broken skin on the hands are likely to sting even when less-irritating formulations are used.
Some disposable gloves are powdered on the inside. After removal of these gloves, some powder may remain on hands, and there is the potential to create a “gritty” residue if in contact with certain alcohol-based hand rubs. Before finalizing purchase of large quantities of gloves and hand sanitizer, testing products will allow identification of combinations which avoid this problem.
RECENT STUDIES FACT;
Many studies have found that sanitizers with an alcohol concentration between 60–95% are more effective at killing germs than those with a lower alcohol concentration or non-alcohol-based hand sanitizers. Non-alcohol-based hand sanitizers may 1) not work equally well for all classes of germs (for example, Gram-positive vs. Gram-negative bacteria, Cryptosporidium, norovirus); 2) cause germs to develop resistance to the sanitizing agent; 3) merely reduce the growth of germs rather than kill them outright, or 4) be more likely to irritate skin than alcohol-based hand sanitizers.
Although alcohol-based hand sanitizers can inactivate many types of microbes very effectively when used correctly 1-10, people may not use a large enough volume of the sanitizers or may wipe it off before it has dried 10. Furthermore, soap and water are more effective than hand sanitizers at removing or inactivating certain kinds of germs, like Cryptosporidium, norovirus, and Clostridium difficile.
Many studies show that hand sanitizers work well in clinical settings like hospitals, where hands come into contact with germs but generally are not heavily soiled or greasy. Some data also show that hand sanitizers may work well against certain types of germs on slightly soiled hands. However, hands may become very greasy or soiled in community settings, such as after people handle food, play sports, work in the garden, or go camping or fishing. When hands are heavily soiled or greasy, hand sanitizers may not work well. Hand washing with soap and water is recommended in such circumstances.
Be wise and be smart for your healthy life.
DR IMAN FIRMANSYAH 
hi doctor Iman ,
the reason it was invented was to use them when one has little or no access to clean water and soap. So are they really good for us considering how often we use them? considering the alcohol contain etc?
will the sweet smell can be highly toxic to our skin?
Hai Ms Maya,
Thanks for leaving a comment on here,
Hand Sanitizers is really safe for using it in term of daily practice which sometimes can be used for cleaning your hand without water. In the condition that really solid dirt or others greasy soiled, it’s strongly suggested and still the best when you clean up your hand with soap and rinse with water.
There weren’t such of studies that have mentioned how often you can use it in a day, but it can be very useful when you apply before eating (but you should still wash your hand with water and soap if you would like to eat with your bare hand as traditional common practice in some Asian countries), you may use it urgently instead of soap and water, and also if your hand feels oily or greasy. As long you can manage to use hand sanitizers with proper rub technic (as I attached in the article), I think you should be fine. And recently on the market, many products have contained less irritating for the skin and yes it’s affordable. If there any adverse reactions related in further, you may resume and see your family doctor to obtain immediate medical assistance.