At ERH Associates, we’re often asked about supplements and natural remedies — whether they work, whether they’re safe, and whether we recommend them.
It’s easy to see why these questions come up. The supplement industry is vast, heavily marketed, and often promises quick fixes or “natural” solutions for everything from low energy to hormone balance. But the reality is more complex — and, in many cases, less reassuring — than the marketing might suggest.
When Supplements Can Be Helpful
Vitamins, minerals, and certain other supplements absolutely have a place in medical care when they are truly needed and supported by strong evidence. For example:
- Prenatal vitamins to ensure optimal nutrition before and during pregnancy — including folate to reduce the risk of neural tube defects and iodine in New Zealand to support healthy brain development in the baby, as New Zealand soils are naturally low in iodine.
- Iron for confirmed iron deficiency, where dosing and duration are tailored to blood test results.
- Melatonin for short-term use in specific sleep disorders, under medical guidance.
In these examples, there is good evidence, the supplement is given for a clear medical indication, and pharmaceutical-grade preparations are available in prescription form.
May Help Some People
Some supplements have a modest evidence base or may help certain individuals, even if results vary. We may recommend these as low-risk options when patients prefer to try them and there are no safety concerns:
- Omega-3 fatty acids — can help some people with dry eye symptoms and may support heart health, although the degree of benefit can vary between individuals and conditions.
- Evening primrose oil — may help some people with cyclical breast tenderness, though not everyone experiences improvement.
Both of these are available over the counter in New Zealand. They are best discussed with your doctor to ensure they’re safe for you and used in an appropriate dose and form.
Why We’re Cautious About Most Non-Prescription Supplements and Natural Remedies
1. Evidence Matters
Pharmaceutical medications undergo years of rigorous clinical trials before approval. These trials establish:
- The exact doses that are effective
- The exact doses that are safe
- The specific health condition it helps
- Potential side effects and risks
In contrast, most supplements and natural remedies arrive on the shelves without this level of testing. Marketing claims are often based on small or low-quality studies, traditional use, or preliminary research that hasn’t been confirmed in high-quality human trials.
2. Unknown Contents
Natural remedies often contain concentrated blends of plant or animal extracts measured by weight. This means the amount of active ingredient can vary — sometimes significantly — from batch to batch, and you may not even know all of the active ingredients in the product.
Pharmaceutical medicines, by contrast, must meet strict international manufacturing and testing standards to ensure consistent purity, potency, and safety. Non-prescription supplements and natural remedies are not subject to the same requirements, so their quality can vary widely between brands and batches.
Even compounds that occur naturally in foods can become risky when extracted, concentrated, and taken in higher doses than you’d get in a normal diet. In supplement form, these higher doses can increase the risk of side effects, toxicity, or interactions with medicines — especially with long-term use or when taking multiple products.
This uncertainty makes it hard to know whether you’re taking too little to have any effect — or too much, risking harm.
3. Safety Concerns
Even “natural” products can cause side effects, interact with prescription medicines, or be unsafe in certain health conditions. For example:
- St John’s Wort can reduce the effectiveness of the contraceptive pill and other medications.
- Some natural remedy blends contain ingredients that can affect liver function or blood clotting.
Natural does not automatically mean safe. Many substances found in nature can be harmful.
4. Regulation Differences
In New Zealand, supplements are regulated more like food than medicine. This means the same strict manufacturing and testing standards don’t apply, and quality can vary between brands. In some cases, what’s on the label may not match what’s in the product.
A Special Note: Biotin and Thyroid Function Tests
Supplements containing biotin (vitamin B7) — often marketed for hair, skin, and nail health — can interfere with some laboratory assays used to assess thyroid function. This interference can cause blood test results to appear falsely high or low, potentially leading to an incorrect diagnosis or unnecessary changes in treatment. If you take biotin, let your doctor and the laboratory know before any blood tests, and follow medical advice on whether to pause it beforehand.
What to Do Instead
If you’re considering a supplement or natural remedy:
- Talk to your doctor first — bring the product label so they can check ingredients and possible interactions.
Bottom Line
Some supplements — like folate, prenatal vitamins, B12, iron, magnesium, melatonin, and a quality multivitamin — can be beneficial in specific situations when used correctly. Others, like omega-3 fatty acids and evening primrose oil, may help some people and are generally low risk, but the degree of benefit varies. Many others lack the evidence, consistency, or safety profile we’ would usually require before recommending them. Natural doesn’t
Supplements aren’t automatically safe or effective even if they’re “natural.” When used in the right context some of them might help but sometimes they cause harm.
Your health decisions are always your own — but our role is to give you the best information so you can make them wisely.
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