What to consider before you buy a supplement (and my top 3 picks)
Photo by Supliful - Supplements On Demand on Unsplash
As a nutritional therapist, two of the most popular questions I get asked about supplements are: "What should I actually be taking?" and “Which supplements are good?”
Before I answer those, I have to be honest first. Because most people arrive at those questions already with a list of the supplements they take. I currently see all my clients online, so before our first session together, everyone completes a questionnaire, and one of the questions asks what supplements you're currently taking.
It's rarely a short answer. Capsules, tablets, powders, bought because a friend swore by it, or an influencer mentioned it, or it just felt like the correct thing to do. Vitamins are good for you, right? And more must be better?
Not quite. And that list is usually the best place to start, because it tells me everything about how confusing this industry has become.
So, before you spend another penny, let's look at what's actually worth considering before you buy, and the three supplements I recommend to most of my clients. Because otherwise, you could just be buying yourself very expensive wee.
What to consider before you buy a supplement
So, before we get to what I actually recommend, here's what I'm weighing up every time a client asks me about a supplement, and what's worth checking before you buy anything at all.
Supplements aren't one-size-fits-all
What worked wonders for your sister, your friend, or that person on TikTok telling you their skin transformed in three weeks might do absolutely nothing for you.
We're all biochemically individual, meaning your body's specific needs, gaps and quirks are yours alone.
Taking a supplement without knowing what's actually going on inside you is essentially guessing. And guessing gets expensive.
Not all supplements are created equally
This is the bit that catches people out most.
The supplement industry is largely unregulated, which means a cheaper product on the shelf can sit right next to a high-quality one, near-identical name, near-identical ingredients, and yet contain poorer-quality ingredients your body genuinely struggles to absorb and use.
Cheap to make and cheap to buy, doesn't mean it does anything once it's inside you.
You might be taking a token amount
Dose really matters.
A lot of the supplements you can grab during your Saturday food shop contain what's called a maintenance dose. That's fine for stopping you sliding backwards, but if you're trying to correct an actual deficiency, you often need a therapeutic dose, a level that's been researched to make a real, measurable difference.
Think of it like trying to fill a bath with an eyedropper. You're not doing nothing, but you're not getting anywhere fast either.
Check what else is in that capsule
Binders, bulking agents, artificial colours, cheap oils, unnecessary additives, sweeteners. Some supplements pack in so many extras that the actual active ingredient is almost an afterthought, sitting towards the bottom of a very long ingredients list.
Always flip the bottle over and have a proper read.
Timing and pairing matter more than you'd think
Some nutrients compete with each other for absorption. Some need food to work. Some do their best work in the morning, some at night.
And this is the bit people aren’t sure of: if you're on any medication, some supplements can interact with it, either dulling how well it works or intensifying its effect. Existing medical conditions matter here too.
This is exactly the kind of thing I look at with every single client, because it's not a small detail - it can genuinely change how safe or effective everything else you're taking is.
What are the top 3 supplements I actually recommend?
Big caveat first, because I'll bang the drum on this one until I'm blue in the face: everyone's needs are different, and a proper personalised plan will always beat anything generic. But if you're after a starting point, these are the three I recommend to the vast majority of clients I work with, based on both the research and my clinical experience.
1. Vitamin D
Vitamin D deficiency is incredibly common in the UK, largely thanks to our, let's say, unreliable sunshine. I see low levels on test results all the time, even in people who assume they're getting plenty because they're out running in shorts and sleeveless tops most days.
We need vitamin D for bone health, muscle strength and immune function, but it also plays a role in mood, heart health, sleep, and has been shown to help reduce inflammation.
You can get some from foods like oily fish, egg yolks, organ meats and certain mushrooms, but not nearly enough to meet your needs, so supplementing is generally recommended.
The NHS suggests we all supplement from around October through to March or April, but the standard 400IU recommended daily amount isn't enough for most people. The only real way to know your correct dose is through testing, and I'd suggest testing every September or October and again in March or April, because your right dose depends on your levels, your height and your weight.
Testing genuinely matters here. If your levels are already low, that basic recommended amount probably won't move the needle. And if your levels are already adequate or optimal and you supplement on top, you can end up with too much, which can be toxic, since vitamin D gets processed and stored in the liver.
A word of caution: if you have kidney disease, high blood calcium, heart problems or sarcoidosis, you need to be careful with vitamin D, as it can push up calcium levels further.
2. Omega 3
Omega 3 is an essential fatty acid, meaning your body can't make it itself, so it has to come from food.
It plays a big role in heart health, brain function and how your body regulates inflammation.
The best food sources are oily fish, and the easy way to remember them is the acronym SMASH: salmon, mackerel, anchovies, sardines, herring. Aim for around three to four portions a week if you can.
You can also get some omega 3 from plant sources like flaxseeds, chia seeds, hemp seeds, pumpkin seeds and walnuts, but the type of omega 3 in these isn't in a ready-to-use form. Your body has to convert it through several stages, and that conversion rate is low, so you'd need to eat an awful lot of seeds and walnuts to get a meaningful benefit.
If you're vegetarian, vegan, or you just don't fancy fish, an algae oil supplement is your best bet, as it provides the useful forms of omega 3, EPA and DHA, directly.
If you're on blood-thinning medication, about to have surgery, or living with diabetes, have a chat with a health professional before supplementing, as omega 3 can affect blood clotting and blood sugar control.
3. Magnesium
Magnesium is involved in hundreds of processes throughout the body, which is a lot for one mineral to be responsible for.
It's needed for energy, muscle function, and supporting the nervous system. Low levels may contribute to muscle cramps, poor sleep, migraines, PMS and stress, and modern diets, along with alcohol and stress, tend to deplete it fast.
Good food sources include nuts and seeds, dark green leaves like spinach, kale and swiss chard, and the best one of all, cacao. Yes, that means a couple of squares of dark chocolate with 70% or more cocoa a day counts as a genuine, nutritional-therapist-approved food source. You're welcome.
The type of magnesium matters too, as they each do different jobs. Magnesium glycinate is my preferred form for supporting relaxation and sleep, while magnesium citrate can help if you're prone to constipation.
If you're on antibiotics, take your magnesium at a different time, a two-hour gap is usually enough. And take care if you're on blood pressure medication or calcium channel blockers.
So, what supplements should you actually buy?
As with most things in nutrition, it depends. Sometimes the answer is a supplement, often at a proper therapeutic dose or in a different form to what's currently sitting in your cupboard. And occasionally, the answer is nothing at all, because your food is already covering it.
The truth is that supplements can be genuinely effective when they're the right one, at the right dose, for what your body actually needs. Used without that information, you're not really supplementing, you're guessing.
If your own supplement list has grown longer than you'd like to admit, you are absolutely not alone, and there's no judgement here. That's such a common starting point for the people I work with.
What I do with clients is get a full picture of where your body is now, what it's been through, what you're eating (and what you're not), how you move, and how you live, so we can work out what's actually going on rather than trying to guess.
Still feeling confused about supplements?
If you fancy having a chat about your own supplement situation, or you're just curious what testing might reveal for you, book a free chat and we can have a look together.