What's wrong with the stuff I can find at my local grocery store?
If you buy the soaps you'll find in the grocery store and read the ingredients you'll find things like etidronate potassium chloride or how about cetyltrimethylamoniumbromide (what a mouthful!). Do you really want to use that on your skin?
Many of the commerically available bars are not even soap, they are detergents. Detergents are great cleaners for your laundry, or your dishes, but not for your skin (Not so good for the environment either). The reason is that detergents clean by stripping away the oils which hold the dirt, and therefore they are very drying to skin.
What's right with the handmade stuff?
Most handmade soap is made with vegetable oils like olive oil, coconut oil, and palm oil. It has extra oil added which stays on your skin to moisturize it after the soap is rinsed away. It also contains glycerin, a byproduct of the chemical reaction that produces soap. Glycerin attracts moisture and holds it so your skin can absorb it. The large manufacturers that do make real soap usually separate out the glycerin and sell it separately to make the lotions and creams you'll need after drying out your skin with detergents.
Goats milk has vitamins and minerals to nourish your skin and it has lipids that help seal in moisture. Goats milk soaps are close to the same pH level as our skin and are therefore more gentle.
Why goats and not cows milk?
All kinds of milk can be used in soapmaking, but goats milk has more vitamins and minerals than cows milk, which is great, but the reason it's better for soapmaking is the structure of it's fatty acids (complicated chemistry stuff). Simply put, it combines more smoothly to make a creamier soap which produces a rich, thick lather. If you like great lather a goats milk soap is the one for you!
Oatmeal has been known as a skincare star since ancient times. Not strait from the carton though. You need to grind it very fine. Ground oatmeal actually binds to the skin and holds moisture there, helping the skin absorb the water.
If you have skin problems (dry, red, itchy, scaly,etc) a 100% natural, perhaps unscented soap with ground oatmeal is a good choice.
Fragrance Oil or Essential Oil
Scent is the most important ingredient for some soap buyers. I've had people buy soap just to make their bathroom smell good. That's great but they need to use it in the bath or shower too. Soap can be scented with either a natural essential oil or a fragrance oil.
Essential oils are concentrated liquids extracted (usually by distillation) from a plant. Fragrance oils are blended synthetic aroma compounds or natural essential oils or a combination of both.
For a soap to be labeled Natural it will usually be scented only with essential oils. But just because it's natural doesn't always mean it's safer than fragrance oil. Some essential oils come with safety warnings. And some essential oils are just too expensive to use in soap making. A half an ounce of sandalwood can cost around $100. Or rose, which is a very popular scent can run you $400. (Yips!) So many soap makers will use both essential oils and fragrance oils in their different selections.
If you are not sensitive to fragrances, choose whatever smells nice to you. But if you have problems with fragrances you should read the ingredients carefully and make an informed decision. All good soapmakers will list their ingredients on the soap labels and on their websites.
Someone needs to invent a way for us to smell things on the internet!
Natural and Synthetic
Color makes soap prettier, but doesn't contribute any skin care benefits. Powdered material from plants can be used to color soap, dyes can be used, or ground mineral pigments can also be used.
Honey is vitamin rich. It has vitamin B,C,D, and E. Also, it's thought to have a
slight natural anti-bacterial benefit.
It adds a light, warm, sweet scent, a bit of extra lathering, and is a humectant (a substance that draws moisture from the air).
Clays have been used since ancient times for masks and skin therapy. They have a slight exfoliating effect and they draw oils and impurities from the skin. A clay mask can unclog the pores and stimulate blood circulation. In soap making clay are most often added to facial and shaving soaps. Except for Koalin, sometimes called white clay, they are slightly astringent since they do take oil away from the skin.
A soap with french green clay added would be a good choice for oily skin.
Herbs are added for color, for healing properties, and just for added decorative interest. There are too many herbs that can be used in soap to list here. If you are interested in a particular one I suggest the website on herbs in the links section.
Other Sites of Interest
Some sites near and dear to me.
MORE OF NATURAL HANDCRAFTED SOAP ON GOOGLE