If you’ve ever stood in front of a supplement shelf wondering what actually works and what’s just clever marketing…you and me both!
As a registered nutritional therapist and health coach, I hear this from clients a lot:
“Should I be taking something?”
“Everyone online is saying I need this supplement, but do I really?”
Firstly, not everyone needs supplements, but for many people (especially those over 40 navigating fatigue, gut issues, hormonal shifts, or simply busy lives) the right ones can make a meaningful difference.
In this post, I’ll share the 3 supplements I recommend most often in my practice and I’ll tell you why they matter for energy, digestion, mood and metabolism.
Start With What’s on the Plate
Before we jump into supplements, let me say this: Food first. Always.
In an ideal world, we’d get everything we need from food. But life isn’t always balanced, and even a good diet might not cover all the base, especially if you’re over 40 and dealing with fatigue, metabolism changes or gut issues.
Soil depletion, busy routines, stress, and even medications like weight loss drugs can all impact nutrient absorption or intake. That’s why I often support clients with targeted supplements, after assessing their diet, lifestyle, and, when appropriate, using testing.
Below are three supplements I return to again and again in practice. Not because they’re trendy, but because they work when used smartly.
1. Vitamin D: The Everyday Essential You Might Be Low In
Vitamin D isn’t just about bones. Vitamin D acts more like a hormone than a typical vitamin (and it has receptors across the body). It supports calcium absorption, immune regulation, hormone health, muscle function, and even mood.
Vitamin D is synthesised in the skin when exposed to UVB sunlight. Specifically, 7-dehydrocholesterol in the skin converts to “pre-vitamin D3”, which then becomes active through steps in the liver and kidneys. Factors like sunscreen use, time indoors, darker skin tone, age, genetics and location can all reduce your body’s production.
Dietary sources like oily fish (think mackerel, sardines, herring, salmon), eggs and fortified foods can help, but are rarely enough to meet needs. Studies consistently show many people, for example in the UK, don’t meet optimal levels through diet or sunlight alone.
Testing and dosage
Test first, supplement second. A simple blood test (25(OH)D) will tell you your vitamin D status; tests can be available from pharmacies, GP or via nutritional therapist.
The UK government recommends 10 mcg (400 IU) daily in autumn and winter, but many clients benefit from higher doses (commonly 1000–2000 IU/day), based on their personal levels and needs.
While vitamin D supplementation is fairly safe, vitamin D does accumulate in the body over time. Therefore, long-term use should be done only under supervision. Balancing it with vitamin K2, to support calcium regulation, is recommended.
2. Magnesium
Magnesium is involved in over 300 enzymatic reactions in the body. It supports:
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- Energy production (ATP synthesis)
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- Muscle and nerve function
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- Blood sugar and blood pressure regulation
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- Sleep and stress response
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- Hormone synthesis and balance
Modern diets, especially those low in whole grains, legumes, seeds or leafy greens, can be low in magnesium. Stress, alcohol, certain medications (like PPIs and diuretics) and digestive issues can also deplete magnesium stores.
Not all magnesium is the same
Magnesium is always bound to another substance, and this affects its absorption and function. Some most common include: example:
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- Magnesium citrate – often used for mild constipation or general support
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- Magnesium malate – for improved energy and supporting healthy gut microbiome
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- Magnesium glycinate – known for its calming effect and better absorption
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- Magnesium oxide – poorly absorbed, but can be used for digestive relief / constipation
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- Magnesium threonate – shows promise for cognitive health, because it’s been shown to cross the blood-brain barrier
Working with a practitioner can help identify which form is best for specific needs.
Magnesium food sources and dosage
Found in almonds, cashews, pumpkin seeds, black beans, spinach and dark chocolate. Daily needs vary (300–400 mg/day for adults), and many people fall short.
Testing isn’t a standard in practice, as most of magnesium stores are in the bones or muscle. The body tends to excrete excess magnesium via urine, so moderate supplementation is generally safe.
3. Omega-3 Fatty Acids (EPA & DHA)
Omega-3s are essential fatty acids. The body can’t make them, so they must be obtained from food or supplements. There are a few types of Omega-3 faffy acids, with EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) being key players in reducing inflammation, supporting heart health, maintaining brain and cognitive function and supporting gut lining and immune function.
ALA, EPA & DHA — what’s the difference?
ALA (alpha-linolenic acid) is found in flax, chia, and walnuts, but only a small percentage is converted to the active forms EPA and DHA. This is why many people, especially those who don’t eat fish, may benefit from supplementing directly with EPA and DHA.
Omega-3s vs Omega-6s
Both omega-3 and omega-6 fats (abundant in processed oils, some processed foods, some seeds and nuts) compete for the same enzymes in the body. That means that a poor omega-3 to 6 ratio can tip the body toward fatty acid imbalance.
Food sources and supplementation
Foods that are great sources of Omega-3 include sardines, salmon, anchovies, mackerel and herring. For those who don’t eat enough oily fish, supplements can help.
When looking at supplements, look for high-quality fish oil with third-party testing (e.g. IFOS certification) and properly stored. Look for at least 1000mg combined EPA/DHA per day, adjusted based on needs.
You may also check out some algae supplements as a vegan alternative to fish oil. Additionally, some supplements may also include added vitamin D or other fats, check labels to avoid doubling up.
So What Does This Mean for You?
Even with a solid diet, some gaps are harder to fill, especially when stress, busy routines, hormonal changes, or low appetite (like when using weight-loss medications) come into play.
What I often recommend clients:
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- Start with what’s already on the plate, track food for a few days (it builds food awareness)
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- Consider testing where relevant
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- Supplement with intention, not guesswork
These 3 supplements aren’t the only ones I use in my nutrition practice, but they are ones I return to again and again when working with clients who want more energy, less bloating, stronger immunity and better focus.
Everyone’s needs are different. Supplementation is most effective when based on real data and paired with real-life strategies.
If you would like help figuring out what’s right for you, book a free 30-minute introduction call and we’ll talk about what’s going on, what you’re currently doing and where nutrition can support the healthier life you want.