Honey is one of those ingredients that don’t need much introduction. It is one of the most used substances in the world, arguably one of the oldest cosmetic ingredients throughout human history.  In fact there are reports that it was used even as far back as 4500 BC in Egypt, in eye cosmetics  and it is even known that Egyptian women used honey, mixed with sodium bicarbonate, for vaginal irrigations!  If you think that is incredibly bizarre, think again, as honey has anti-bacterial properties which could explain such uses.
Honey is of course derived from bees but it is not a single compound but rather a natural mixture. This mixture contains mainly fructose and glucose (=natural sugars hence why it is sweet) but it also contains proteins, amino acids, vitamins, enzymes, minerals and other minor compounds.  Because of the highly complicated mixture of compounds that make up honey, it is very difficult to scientifically pinpoint exactly how honey works in cosmetics, especially in complicated processes such as skin care. Interestingly, despite the lack of full understanding, the hydrating effect is often attributed to its high sugar content (sugars form hydrogen bonds between them and water) and the amino acids present (mainly proline but also arginine, alanine, glutamic acid, aspartic acid, lysine, glycine and leucine). 
It is well known to have healing properties and has been used since the ancient times on wounds and burns.  It can moisturise wounded tissue, help against microbial infections, sooth inflammation and even though it is sticky, it can prevent dressing from sticking on to the wound. [1, 5] Honey has been proven to induce tissue repair processes such as angiogenesis (=the development of new blood cells), induce the production of tissue repair molecules and more. [6, 7] It has also been trialled in a lot of dermatological treatments such as acne, skin rashes, contact dermatitis  and has been reported to boost skin radiance and depigment (=reduce or remove pigmentation) skin and hair.  Perhaps honey is not your best friend if you have dyed hair!
As expected, honey is mostly used in skin care, for its moisturising properties, but also to help reduce wrinkle formation.  It is a great ingredient for babies or those with sensitive skin or in products that have “irritant molecules”, like sun screens, to help soothen the skin. Hydroxypropyltrimonium honey is particularly good for hair and dry scalps as it can penetrate the hair structure deeply and help restore elasticity and flexibility. [1, 10]
To this day honey is mainly used in the pharmaceutical industry for its antimicrobial properties.  Interestingly, this varies amongst different types of honey, some are better antibacterial agents than others and it usually depends on the honey’s water content (has to be low), pH (also has to be low) and the activity of the enzyme glucose oxidase (how fast/much can it release hydrogen peroxide). 
It is said that floral sources of honey have higher antibacterial activity, with Manuka honey being one of the best for this.  However, other honey types have also demonstrated great activity against Malassezia yeasts, dermatitis, and dandruff, and there is even some evidence that it can be used to alleviate labial and genital herpes. [1, 12, 13]
Another type of honey worth mentioning is the one from black locust (Robinia pseudoacacia L.) also known as “acasia honey” as it can be often preferred in cosmetics for its ability to avoid the formation of crystals.  Have you ever noticed that if you leave honey stand for a while it forms white crystals at the bottom? You can imagine that this sort of behaviour would completely ruin a formulation so you wouldn’t want that to happen in a cosmetic product that contains honey. Acasia honey contains higher amounts of fructose, than glucose sugars, and as fructose is the one that is more water soluble out of the two, it prevents this crystallisation (=solidifying of a compound to make a crystal) from happening in cosmetics. 
Honey of all types can be found in a range of cosmetics, in different amounts, varying from 0.5-5% in foaming products, creams and emulsions (=an emulsion is a mixture of liquids that are suspended in each other and do not dissolve in each other like for example water and oil) and 10-15% in some ointments. [1, 14]
It is also often used as a vehicle to include herbal extracts in a formulation, usually botanical fats in water-in-oil or oil-in-water emulsions.  It can be an alternative emulsifier in body care and can even be used in concentrations as high as 50%! Addition of 3-20% of honey in shampoos has been reported to help maintain waves and make hair easier to comb.  It can also be found in high quantities (1-10%) in lip products such as lip ointments, in cleansing milks, hydrating creams or gels, after sun care products, shampoos and conditioners. [1, 16]
From a chemist’s perspective, honey is made of sugars, mainly fructose and glucose, proteins and amino acids, vitamins like ascorbic acid (=vitamin C), biotin, nicotinic acid, pantothenic acid, pyridoxine, thiamine, enzymes such as diastase, invertase, glucose oxidase and catalase, minerals such as potassium, magnesium, phosphorous, calcium, iron and copper and other minor compounds.  Even though it is a highly complicated mixture of many compounds, honey is a safe ingredient although some people can experience allergies or sensitisation.
Like any other ingredient, honey can be found in cosmetics under many different names including: Honey, Mel, Mel extract, hydrogenated honey, hydroxypropyltrimonium honey, 2-hydroxy-N,N,N-trimethyl, 3-honey ethers or chlorides etc.  It is classed as an emollient (=softens and soothes the skin), humectant (=locks moisture from escaping the skin) and moisturising ingredient. 
Honey has been proven to have all sort of beneficial properties beyond the yummy type. It can be an amazing ingredient in cosmetics and it attracts research and formulation interests even to this day. Further research might shine more light on the chemical and biological properties of this amazing mixture, and chemically modified forms of honey might enhance it even more. This extraordinary natural ingredient can even support the agricultural development of underdeveloped countries  and provide you will all sort of skin care love. It is definitely a good ingredient to find in cosmetics and is worth seeking out. Anyone else craving honey now?
- Marion C., Use of unfermented honey as an agent for depigmenting and/or lightening the skin, body hair or head hair and/or treating liver spots, 2000, patent n FR2788693.