Gopherhead

Rhodiola is typically considered to be an “adaptogen” and is believed to invigorate the body and mind to increase resistance to a multitude of stresses. The key active constituents in Rhodiola are believed to be rosavin, rosarin, rosin and salidroside.

It is supposed to:

Promote weight loss
Work as an aphrodisiac
Relieves stress
Enhance athletic performance
Be a tonic for well-being
Be an immune enhancer
Improve cognitive function
be an anti-depressant

In controlled placebo studies it has been demonstrated to do all of the above. It is thought to be quite safe. There are no known contraindications or interactions with other drugs/herbs, but there is some potential for allergic reactions in some individuals.

Something similar that I've been using for a few weeks now is Maca. It is also called Peruvian Ginseng, and is a Peruvian plant (sort of like a radish) used for restoring energy, vitality and fertility. It helps to :

Boost libido
Regulate hormonal secretion
Increase energy
Improve memory
Fight depression

Maca isn't an herb or vitamin, though, it is a food and because of this it is thought to be quite safe - just like eating sweet potatoes, or oatmeal. Because of this it is difficult to assign a dosage to something that is typically eaten as a food. Maca capsules generally contain 500mg of dried maca with dosage recommendations in the range of 3-5 grams/day. It has not been found to cause toxicity or adverse effects. However, if you are pregnant, lactating, or have any medical condition, you should consult your physician before taking maca as a therapeutic.

Because you seem to develop a tolerance to certain herbs you might try cycling them. Use one for a few weeks and then switch to another for a few, going back to the original and starting over again. You might try going back to Ginseng and cycling this as well (it is an adaptogen like Rhodiola)

HTH
Nat

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A foolish consistency is the hobgoblin of little minds.