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Originally published on 21st May 2016 Last updated on 5th August 2019
There are certain supplements that support thyroid function and maintaining optimal levels. It’s important to consider other possible problems, so not just your thyroid, such as low vitamin levels and other health conditions that can cause symptoms similar to hypothyroidism.
Supplementing may help with symptoms.
I would always recommend consulting your doctor, pharmacist, a medical professional etc. before making any changes to your health regimen. It can be dangerous if you take supplements and already have high/sufficient levels. Of course, all pregnant women should be especially careful and consult a medical professional.
Although I have qualifications in diet and nutrition, I’m not medically trained.
None of the linked supplements below are endorsed or recommended by myself either. They are there for information and as examples.
If you’re gluten, soy or dairy-free, or have any other restrictions, do also always check that all supplements you take are free of the substance, too.
Most Vitamins Can Be Tested via Doctors’ Tests to Learn Your Levels
Supplements Worth Considering and Testing For
B Vitamins/B-Complex – (B1, B2, B3, B6, B12)
These can help with tiredness, fatigue, metabolic function and support adrenal health and function. Vitamin B-12 and folic acid are both important for energy and heart protection. Folic acid is also good for preventing neural tube defects in a developing baby. It is also needed in order to make TSH.
B3 is needed to keep all the body’s cells (including the endocrine glands) in efficient working order. People with hypothyroidism may struggle to absorb B12. A lack of B12 can cause mental illness, various neurological disorders, neuralgia, neuritis and bursitis.
You can find this supplement online rather easily, but I’ve linked to an Amazon one, here: Solgar 500 mcg Vitamin B12 Vegetable Capsules – 50 Capsules.
For many thyroid patients, low iron levels can cause fatigue, heart palpitations, aches and pains and a lack of stamina.
Iron is central to the production of both red blood cells and thyroid stimulating hormone (TSH). Iron is also important for your thyroid health as it makes the hormone T4, and converts T4 to T3. , 
Always have your levels tested before taking a supplement as taking extra iron can be dangerous.
Bisglycinate is a popular type of iron as it doesn’t cause stomach issues or constipation. You can find it here: Solgar Gentle Iron – Iron Bisglycinate – 180x20mg Vegicaps
An antioxidant, vitamin E is a fat-soluble vitamin important for many processes in the body, including producing TSH.
Selenium supports the conversion of storage hormone T4 to active thyroid T3. Without it, T3 cannot be produced in the right amounts, and organs will function as if they are hypothyroid even though blood test levels are ‘normal’.
It has also been shown to lower thyroid antibodies. 
Essential for the immune System and adrenals. The adrenal gland contains the highest concentration of vitamin C in the body. Vitamin C plays a crucial role in both the adrenal cortex and adrenal medulla, which are responsible for responding to stress.
A controversial one, many say you should only supplement it if you are definitely low in it, as it can do more harm than good if not. Sufficient iodine is needed to make thyroid hormone T4.
If you are looking to supplement iodine, you can find it on Amazon here: Lugols Iodine – a 12% Solution 30ml
Vitamin D3 and A
Good for joints and fatigue, a deficiency in Vitamin A or D can also stop T3 from correcting your metabolic rate and so leave you with low energy, cold intolerance and weight gain.
Vitamin A must be accompanied by protein to make it available to the body, so if you are on a low-protein diet, you may be deficient in this. If you are low on Vitamin A, your ability to produce TSH is limited. This vitamin is required by the body to convert T4 to T3.
Vitamin D has also been shown to lower antibodies. 
A popular vitamin D supplement can be seen here – Solgar, Natural Vitamin D3, 1000 IU, 180 Tablets.
You should always take Vitamin D with Vitamin K2. K2 regulates calcium in the blood, so combining Vitamin K2 withVvitamin D3 is highly recommended because of the synergy between the two vitamins.
Research shows a slower progression of calcification in those taking both Vitamin K2 and Vitamin D compared to those taking Vitamin D alone. 
Needed in order to make TSH, research has shown that both hypothyroidism and hyperthyroidism can result in zinc deficiency. It also plays a role in the functioning of the immune system. Low zinc levels have been found to be common in obese people. Zinc is needed to convert T4 into T3.
Fish Oil/Omega 3/Cod Liver Oil
Cod Liver Oil is one of the best sources of omega 3 fatty acids (EPA and DHA) and contains relatively high amounts of Vitamin A and D. Good for lowering high blood pressure, reducing risk of osteoarthritis and maintaining joint and bone health.
You can find it on Amazon here: Omega 3 Fish Oil 1000mg
Needed in order to make TSH and for the conversion of T4 into T3, it seems that a diet high in refined food and caffeine will encourage magnesium loss. Magnesium can also help cramps, energy and aches and pains.
Magnesium Malate and Chelate are the most popular among thyroid patients, so I’ve provided a link to Magnesium Chelate here: Doctor’s Best High Absorption 100% Chelated Magnesium (120 Tablets)
Probiotics provide ‘good’ gut bacteria that can improve overall gut health and strengthen the immune system. There are tablet/capsule forms: Natures Aid Pro-100 Ultra Ultimate Strength Probiotic Complex and Kefir (drink form): Kefir Drink
Bone broths are easy to make at home, but if you struggle to find the time like myself, this one is a good option to buy readymade: Premium Beef Bone Broth Gelatin.
Bone broths helpful in treating leaky gut, because the collagen helps to heal the gut wall and aid digestion. The protein also helps to build muscle. They can also help with inflammation such as aches and pains in the joints and muscles.
Digestive enzymes can be brilliant for improving gut health and absorption of vitamins and minerals from food, encouraging regular bowel movements and more.
Is There One Really Good Multivitamin That Incorporates All That is Needed in an Effective Dose?
We’re often advised against multivitamins, as the amount of each vitamin contained in them is usually so small, that it doesn’t do an awful lot. Or we’re told to avoid them because different vitamins can cancel each other out when taken together (or affect each other’s absorption).
However, my functional medicine practitioner had me take a pregnancy multivitamin which she said were the best kind to take if you have to (i.e. due to finances).
What Supplements Do I Personally Take?
Many have asked what I specifically take day to day but it changes so often, that I couldn’t keep you continually updated. Supplements are not intended for lifetime use, so a practitioner should be continually reviewing what you do and don’t need. Our needs change over time.
You can click on the hyperlinks in the above post to learn more and see references to information given.
Rachel Hill is the highly ranked and multi-award winning thyroid patient advocate, writer, speaker and author behind The Invisible Hypothyroidism. Her thyroid advocacy work includes writing articles, authoring books, producing her Thyroid Family email newsletters and speaking on podcasts, as well as being a founding board member for the American College of Thyroidology. She is well-recognised as a crucial and influential contributor to the thyroid community and has a large social media presence. Her books include “Be Your Own Thyroid Advocate” and “You, Me and Hypothyroidism”.