Rosemary for Thyroid Health

Rosemary may possibly help with hypothyroidism, but targeted research is lacking.

• Antioxidant and anti-inflammatory activity. These effects may potentially help with hypothyroidism and its symptoms.
• Potential improvement of thyroid signaling through enhance thyroid receptor activity.

Overview

Rosemary (Rosmarinus officinalis) is a woody herb that belongs to the mint family of plants. It is known for its fragment smell, and is used in medicine, food preservation & flavoring, and making perfume. Rosemary has notable health effects such as:

• Stimulating hair growth
• Reducing anxiety and other nootropic benefits
• Reducing inflammation
• Antioxidant activity
• Improving blood flow

In terms of thyroid health, rosemary oil is sometimes used topically to help with hair loss, joint pain, and other symptoms of an underactive thyroid gland. In addition, some believe that rosemary can help enhance thyroid hormone signalling and reduce thyroid inflammation, but these  uses lack strong evidence.

How Rosemary Might Help With Thyroid Health

Rosemary contains bio-active phytochemicals such as rosmarinic acid, camphor, caffeic acid, ursolic acid, betulinic acid, carnosic acid and carnosol that may aid thyroid health through:

Antioxidant and anti-inflammatory activity

Rosemary contains several compounds – most notably rosmarinic acid – which have antioxidant and anti-inflammatory properties.^{1 2} These activities may help manage hypothyroidism symptoms and possibly reduce the inflammation involved in autoimmunity-related thyroid disorders such as Hashimoto’s.

Potential enhancement of thyroid signaling

Another potential way thyroid benefit of rosemary is enhanced thyroid hormone signaling. When thyroid hormone receptors (TRs) found in cells are activated by thyroid hormone, they can exert their effects as one of three molecules:

• Monomer – a single molecule
• Homodimer – two TRs combined together
• Heterodimer – one TR combined with one retinoid X receptor (RXR)

The heterodimer form has the strongest response to thyroid hormone, and as such is considered the most active.³ Because a single study in isolated cells reported that application of carnosic acid (found in rosemary) increased the number of retinoid X receptors (RXR), the theory is that an increase in RXR helps make TR more responsive to thyroid hormone.

However, this mechanism requires further evidence and remains largely theoretical. ^{4 5}

Rosemary’s Popular Uses for Thyroid Health

Multi-ingredient thyroid supplements sometimes include rosemary because of the belief that it enhances thyroid receptor signalling, therefore enhancing the effects of thyroid hormone. However, this potential mechanism has little evidence and remains purely hypothetical.

In addition, some people use rosemary topically to fight certain symptoms of hypothyroidism such as hair loss, hair thinning, and joint pain. Although these uses have not been tested in the context of thyroid issues, there is some evidence that rosemary oil can promote hair growth and reduce inflammation when applied topically. ⁷

Research

There are currently no studies on the use of rosemary for thyroid health. Most of the evidence for rosemary’s benefits is indirect, meaning that it could be beneficial but has not actually been tested in the context of thyroid health. As a result, there is no way to confirm whether it has any thyroid benefits.

Dosage for Thyroid Health

• There is no established dosage of rosemary for thyroid function
• Rosemary supplements typically supply 275 – 500 mg of rosemary extract in capsules or come in the form of essential oil
• Multi-ingredient thyroid supplements typically provide 80 mg of rosemary leaf extract

Available Forms

• Capsule or tablet, which may be standardized to contain a certain amount of carnosic acid
• Essential oil – applied topically
• Tea