Ashwagandha is building by nature, in fact I have noticed increased muscle mass from it's use. It helps strengthen the body and even builds more blood along with its moderate levels of iron to prevent anemia. It rebuilds the nerves and even reverses synaptic loss! It is good for any neurological condition including Dementia, Parkinson's, Multiple Sclerosis, Fibromyalgia and nerve atrophy with clinical herbalists and their clients confirming it's effectiveness. Keep in mind everyone is different and may need a different herbal formula to match the individuals systemic and energetic health patterns that are unique to them.
For a great article about the science behind it's benefit on Alzheimer's disease read this: https://blog.lifeextension.com/2014/09/ashwagandha-for-alzheimers-disease.html?fbclid=IwAR25t99gVEL1OIIZAseSt_8z-IrM-UVnlDYlkgz_IKdiYrrBiAzX4OV58Uk
In Ayurveda ashwagandha is called a "medhya rasayana" which is associated with the brain, memory, cognition, intellect, lifespan, concentration, creativity and those sorts of things.
Yes ashwagandha is even good for the intellect. This factor I would attribute to it's ability to make someone more "grounded" and more present, because when you are not "fully there" or here, then you are more stuck in your head other places not able to see things as clearly and with a more calm collected and more neutral perspective. Along with reducing anxiety, ashwagandha is very popular for regulating sleep cycles, so if you have jet lag then taking it at any part of the day should help. It does not make you tired, but it regulates your hormones so that you may be tired in more appropriate times. If this does not work for insomnia try TCM blood tonics which may help over a long period of time and before bed try albizzia or valerian root (valerian may increase "heat" and cause prone individuals to be too "hot" to sleep). If nothing else works, see a professional herbalist.
Ashwagandha also is great for male reproductive health, but also helps females as well. If a mans sperm is not healthy this will help. In addition it will increase libido for men or women. After all it is said to give the strength of a horse...
This herb will help with inflammation such as joint pain and even has benefit in autoimmunity. Ashwagandha is technically a type of nightshade and some people develop inflammation reactions to nightshades, however ashwagandha seems to be the exception to the rule. Tomatoes are the main nightshade that causes inflammation, so if you don't get it from tomatoes then it's probably not of a concern for you, and ashwagandha would most likely reduced the reaction to tomatoes ironically.
Ashwagandha is a specific remedy for hyopthyroidism through stimulating the thyroid directly as well as helping relieve the associated symptoms.

Shatavari is also amazing but has not yet hit mainstream popularity and therefore has less science. So lets dig into what Ayurveda says!
Shatavari also gives strength to the body and builds the sexual life force but is generally considered more specific for women. In addition to building the sexual energy it also rejuvenates the female sex organs and is good for fertility and said to prevent miscarriages along with increasing breast milk and sperm production. It is moistening and therefore great for dried out itchy skin types along with irritated mucous membranes of the digestive tract such as ulcers , colic, or irritable digestion. It is also great for internal bleeding.
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https://www.youtube.com/watch?v=0Sy7jk4cO30