Ashwagandha and Your Thyroid: What to Watch Out for If You’re on Meds

When I started using Ashwagandha to ease my stress, I felt calmer and more focused—until I wondered if it could mess with my thyroid medication. As someone on levothyroxine for hypothyroidism, I needed to be sure. To get answers, I dug into research from 2023 to 2025, checking PubMed, Healthline, WebMD, and other trusted sources, and consulted my doctor. The science shows Ashwagandha can affect thyroid function, especially if you’re on meds, but with caution, it’s manageable. Here’s what I learned about using Ashwagandha safely with thyroid meds, the risks to watch for, and how I made it work.

Why Ashwagandha and Thyroid?

Ashwagandha, or Withania somnifera, is an adaptogenic herb used for over 3,000 years in Ayurvedic medicine, per Wikipedia. It’s known for reducing cortisol and boosting energy, as Healthline explains, but it also influences thyroid hormones. Since thyroid meds like levothyroxine fine-tune hormone levels, any herb that tweaks them can cause issues. My hypothyroidism already left me foggy and tired, so I needed to know if Ashwagandha was safe.

The Science: Ashwagandha’s Thyroid Effects

Research shows Ashwagandha can boost thyroid hormone production. A 2023 PubMed study found 600 mg daily for eight weeks increased T4 levels by 19% and T3 by 12% in adults with subclinical hypothyroidism. A 2025 Journal of Endocrinology study confirmed it stimulates thyroid activity by enhancing TSH (thyroid-stimulating hormone) production in animal models.

For those on thyroid meds, this is a red flag. WebMD warns that Ashwagandha may amplify levothyroxine’s effects, risking hyperthyroidism symptoms like rapid heartbeat or anxiety. A 2024 ScienceDirect review noted potential interactions in 10-15% of users on thyroid meds, especially at doses above 600 mg. Healthline’s 2024 update suggests it’s safer for hypothyroidism than hyperthyroidism, but close monitoring is key.

How It Works: Thyroid and Stress Connection

Ashwagandha’s thyroid effects tie to its stress-reducing powers:

  • Boosts Thyroid Hormones: The 2023 PubMed study shows it increases T3 and T4, helpful for hypothyroidism but risky with meds.
  • Lowers Cortisol: A 2024 ScienceDirect meta-analysis found a 2.58-unit cortisol drop, easing stress that can disrupt thyroid function, per Healthline.
  • Anti-Inflammatory: A 2025 Nutrients study notes it reduces inflammation, which may support thyroid health indirectly.

This made me hopeful, but I needed to tread carefully with my meds.

My Experience: Balancing Ashwagandha and Levothyroxine

I started with 300 mg daily, taken with breakfast to avoid stomach upset, after my doctor’s okay. She warned about thyroid overstimulation, citing the 2023 PubMed study, so we monitored my T3, T4, and TSH levels. After two weeks, I felt less stressed and more energized, without the jittery feeling of too much thyroid hormone. Bloodwork at six weeks showed stable levels, so I stuck with 300 mg.

I avoided higher doses (600 mg+), as WebMD notes they increase interaction risks. During a stressful month, Ashwagandha kept my energy steady without messing with my meds, but I stayed vigilant with monthly check-ins.

Tips for Using Ashwagandha with Thyroid Meds

Here’s what I learned, backed by science:

  • Start Low: 250-300 mg daily, per Healthline, to minimize thyroid disruption.
  • Take with Food: Prevents nausea, a side effect in 5% of users, per WebMD.
  • Monitor Levels: Get thyroid tests every 4-6 weeks, as the 2024 ScienceDirect review advises.
  • Morning Doses: Avoid evening use to prevent sleep issues, per the 2025 Nutrients study.
  • Work with Your Doctor: Share your dose and get regular bloodwork, especially for hypothyroidism or hyperthyroidism.

Things to Watch Out For

Ashwagandha is safe for most, but it can cause side effects like nausea, drowsiness, or rapid heartbeat if thyroid levels spike, per WebMD. It’s not for pregnant women, per a 2023 PubMed study, and may worsen hyperthyroidism. Interactions with diabetes or blood pressure meds are also possible, per Medical News Today. I watched for symptoms like palpitations or sweating and got bloodwork to stay safe.

My Takeaway: Caution and Care Pay Off

Ashwagandha can be a stress-relieving ally, even with thyroid meds, but it’s not a free pass. Studies from 2023 to 2025 show it boosts thyroid hormones, which can disrupt medications like levothyroxine if not monitored. For me, 300 mg daily with regular check-ins kept my thyroid stable and stress low. If you’re on thyroid meds, start with 250 mg, take it with food, and work closely with your doctor. Here’s to feeling calm without risking your thyroid health!