Klorane offers a very good line of shampoos - they are well-known for their plant research - and over the years I have tried many of their products. One I always go back to whenever I need some strengthening action for my hair is their quinine-based shampoo called Klorane Fortifying Treatment Shampoo with Quinine and B Vitamins. My husband who is a more recent user also gives it two thumbs up.
There are a number of other shampoo brands that use Quinquina or Jesuit's Bark or Cinchona and it would be interesting to compare them, but at this point I can only say that this shampoo is effective and this is the reason why I have remained faithful to it. Quinine was used as early as during the Inca period. Klorane's quinine is said to be grown in the Amazon region where the extracts are sun-dried for maximum potency....
"The combination of Klorane Cinchona extract and vitamin B complex provides a mild cleansing, detangling and volumizing base. They activate the scalp's micro-circulation and stimulate the hair to encourage the growth of healthy, strong hair. It is also hypoallergenic."
The fortifying action you may need for reason of seasonal variation or due to stress, for example. Or to maintain long hair. If you start noticing more hair shedding than usual, this is a very good, mild answer to your problem which requires a low level of maintenance. Only one application is necessary and you may choose to use the companion conditioner or not. You may not even need to use it all year round as it seems to work well as an episodic treatment to give a burst of vitamins to your scalp and hair.
Another effect that is not advertised but which I have noticed is that this quinine shampoo leaves some auburn, reddish highlights in your hair, which may be desirable or not, but can bring some nice glow to chestnut and brunette hair. I think that on blond hair it would give them a Venetian hue. Klorane offers a particularly red and dark formulation. The coloring effect is not too strong but it is noticeable.
Places that carry this shampoo are Spalook.com and Cosmeticsolutions.biz starting at $13.