There is some evidence from a few small studies that the western diet has changed significantly in the last 20 years and there are certain vitamin and mineral deficiencies likely to be found in a typical American diet.

There are nutrients and herbs that have the potential to affect hair growth in a positive or negative way.
There are three basic ways that nutritional diet vitamin supplements and amino acid supplements may act influence the hair follicles. The mineral rich and vitamin supplements may act directly on hair stimulating or inhibiting growth activity or they may act indirectly through other intermediaries. For example, a vitamin supplement or herb may influence the production of a hormone to which hair follicles are sensitive. This change in hormone activity in turn may change the activity of the hair follicles.

Some minerals and vitamins can influence the activity levels of another vitamin and minerals. For example, intake of lysine, vitamin B12 and vitamin C help in absorption of other factors like iron. It is worth bearing in mind that the complexity of the body means there are many potential interactions for even the simplest nutrient.

Vitamins for hair & hair growth
Since Vitamin C, helps the absorption of other factors, it is of some significance. Others are of secondary importance to hair growth like vitamin E. Vitamin E is necessary to provide good blood circulation to the scalp by increasing the uptake of oxygen. Not fundamentally required in a hair growth supplement, vitamin E is often present largely because people expect to see it in the ingredients - and the customer is always right!

Other common ingredients like the amino acids - L-Cysteine and L-methioine are of questionable value. Although they are fundamentally required for good hair growth, even a rather unhealthy diet should provide enough of these amino acids and supplementation is rarely required.

Vitamin supplements' vitamins
The supplement industry is worth several billion dollars a year and it is still growing rapidly. Vitamin supplements, mineral supplements and herbal supplements available on net come in all shapes and forms, many of which are specifically advertised to promote healthy hair growth.

These 'vitamin supplements' vitamins are marketed by different names such as liquid vitamin supplements, natural vitamin supplements, daily vitamin supplements, nutritional vitamin supplements and also by such names as mail order vitamin supplements or best vitamins supplements.

But the for the most part, with a few notable exceptions like vitamin A & Folic acid, taking these supplements probably does not harm hair growth. But whether they can really help promote hair growth depends on what the actual cause of the hair loss is and how the supplements or active ingredients in herbs interact with the hair follicles.

Vitamin and herbal supplements
To buy online health supplements or herbal treatment requires you to go for quality. Unfortunately there is no universal method by which quality supplements can be identified. So it is best to depend upon the natural vitamins supplements or fresh foods.

Typically, vitamins and minerals are most concentrated in fresh foods, the older the food is, and the more processed it is, the less nutritious it is. So in principle, the average diet of the early twenty first century may be more deficient in certain nutrients required for healthy hair growth compared to the average diet of the mid to late twentieth century, but it should be emphasized that vitamin and mineral deficiency is still rarely a cause of hair loss.

Hair loss vitamins & minerals
In other words, do not waste your time on searching for vitamin supplements on net unless you have a deficiency detected by a blood test. A comprehensive test for vitamin and mineral levels when one or more is suspected as a cause of hair loss would include; serum iron, serum ferritin, and total iron binding capacity, serum zinc. The deficiency which directly affects hair growth can be related to vitamin (H) biotin, Vitamin B6 and Vitamin B12. You can go for testing for others if they are on offer, but biotin and B6 testing is enough to cover 95% of vitamin deficiencies related to hair loss. And only when such a deficiency is detected by the tests that you need to buy and eat the 'vitamin supplements' vitamins. So the bottom line is that it is better to have the natural supplements through a balanced diet.