Ashwagandha and Thyroid Medication: The Interaction

Ashwagandha, Withania somnifera, raises the output of thyroid hormone, and taken alongside levothyroxine or another thyroid replacement it adds to the drug's effect, so that a person on a settled dose can drift into the signs of excess: a racing heart, heat, sweating, sleeplessness, weight loss, and agitation. Modern study has found rises in thyroid hormone levels in people with a sluggish gland who took the root, and case reports of thyrotoxicosis in people taking it with medication or with an already active gland. Ayurveda reads the same thing from the plant's properties. The root is ushna, heating in potency, and balya, strength-giving; it kindles agni, the digestive fire, and the fires of the tissues, and a gland that is already being driven is driven further. The interaction is therefore stated plainly, once: Ashwagandha interacts with thyroid medication and with sedatives, and a person on either who takes it needs the dose of the drug watched.

The plant and its properties

Ashwagandha is bitter, astringent, and sweet in taste; light and unctuous in quality; heating in potency; sweet in vipaka, the post-digestive effect; and its prabhava, the specific action, is that of a rasayana, a rejuvenative, and a vajikarana, a strengthener of virility. It pacifies Vata and Kapha and, in quantity or in a hot constitution, raises Pitta. Its name means the smell of a horse, for the odour of the root and the strength it is said to give. The Bhavaprakasha places it among the plants that build the body and calm the mind, and the modern pharmacopoeia lists the root.

What it does to the thyroid, in the tradition's terms

Ayurveda has no thyroid as an organ, but it has the conditions. Galaganda, the swelling of the neck that the Sushruta Samhita describes, is the goitre. The sluggish state, hypothyroidism, is read as a Kapha and Vata condition with mandagni, dull fire: weight gain, cold, dryness, constipation, heaviness, hair loss, slow pulse, and a slow mind. The overactive state, hyperthyroidism, is a Pitta and Vata condition with tikshnagni, sharp fire: heat, hunger with loss of weight, tremor, a fast pulse, sweating, loose stool, and anxiety.

Ashwagandha, being heating and building, is a plant for the first condition and not the second. It warms a cold, sluggish body, steadies the Vata that drives the anxiety and sleeplessness of the depleted, and builds the tissues that a dull agni has failed to nourish. In hypothyroid Kapha-Vata it is the classical rasayana of choice. In an overactive gland it is contraindicated on the same reasoning: heating added to heat.

With levothyroxine

A person on replacement is, in the tradition's terms, already receiving the heat that the gland does not make. Adding Ashwagandha raises the body's own output and the combined effect overshoots. The signs of overshoot are the Pitta signs listed above, and their appearance is the reason to stop the root and have the medication rechecked, not to reduce the root and continue. Where the plant is used alongside replacement, and it often is in those with autoimmune thyroid disease and a weak, cold constitution, the practice is to begin at the low end of the dose, to give it with milk rather than with a warming vehicle, and to have the hormone level measured after some weeks, since the dose of the drug may need to fall. A person on sedatives is told the same: the root deepens sleep and calms, and it adds to a benzodiazepine or a sleeping drug.

Dose and form

The classical dose of Ashwagandha churna, the root powder, is 3 to 6 grams once or twice a day. The vehicle is warm milk, which is its classical anupana and the one that best carries its building action; ghee for a dry Vata person; and warm water for a Kapha person who does not want the weight of milk. It is taken in the morning for strength and at bedtime for sleep, and not with food. Ashwagandharishta, the fermented preparation, is given at 12 to 24 millilitres with an equal quantity of water after food, and is the form used where digestion is weak. Ashwagandha ghrita and Ashwagandha taila, the medicated ghee and oil, are used for wasting and for massage in Vata disorders. As a rasayana it is taken for a season, autumn and winter being its seasons, and rested in summer, when its heat is unwelcome.

When it is not given

It is not given in an active Pitta condition: hyperthyroidism, fever, acute inflammation, bleeding, a hot rash, or a burning gut. It is not given over ama, the residue of poor digestion, when the tongue is thickly coated, because a building rasayana feeds the residue first. It is not given in pregnancy in the classical practice. It is heavy for a Kapha person with mandagni and is given with warm water, honey, and long pepper if given at all. Herbalism uses the same root under the same name and states the same interaction.

Not medical advice.