A good running top should be one of the least noticeable pieces of kit you own. It shouldn't cling when you sweat, rub after an hour on the road or restrict your movement. But with running T-shirts, vests, long-sleeve tops, technical fabrics and different fabric weights to choose from, what actually makes a good running top?

Of course, some of it comes down to personal preference and what you need the top to do for you. What feels great to one runner might not work for another. But there are a few important things worth considering: material, fabric quality, weight, fit and construction.

1. Start with the material

The biggest difference between an everyday T-shirt and a purpose-made running top is usually the fabric. Running generates heat and moisture, so you want a material that helps move sweat away from your skin and dries relatively quickly.

Technical synthetic fabrics such as polyester and nylon are common because they're lightweight, durable and absorb much less moisture than cotton. Fabrics can also be engineered with different knits and structures to improve airflow, moisture management and stretch.

Is cotton good for running?

For a short, easy run, you can run in almost anything. The problem with conventional cotton appears as you sweat. Cotton is highly absorbent, so it can become wet and heavy and take longer to dry. On longer runs, damp fabric moving against your skin can also contribute to rubbing and chafing.

That's why technical running T-shirts generally use synthetic performance fabrics for their sweat-wicking qualities. But anyone who's been given a cheap poly tee at the end of a race will know that not all synthetic fabrics are the same.

2. Not all polyester is created equal

Polyester describes the fibre. It doesn't tell you the quality or performance of the finished fabric. The yarn, knit structure, weight, softness, stretch and finishing all affect how a running top feels, manages moisture and performs as the miles build.

At the cheaper end of the market, the priority can sometimes be creating a striking graphic at a low cost rather than investing in the underlying fabric, fit and construction. The result can look every bit like technical running kit without necessarily delivering the performance to match.

So don't judge a running top purely by the design printed onto it. Think about the texture, weight, sweat management and construction, and whether it has genuinely been designed for running.

Style matters. But the performance substance underneath it matters more.

The first thing our customers often comment on with our Essential Tee is its second-skin softness, with many saying they forget they're wearing it while running - and that was always the intent.

3. Consider the weight of the fabric

Fabric weight isn't something most of us look at when buying a top, but it can matter depending on what you want it for - from everyday miles to PB race day.

Textiles are often described in GSM (grams per square metre). Generally, a lower GSM means a lighter fabric, while a higher GSM means a more substantial one.

As a broad guide, technical running tees can range from around 80–90 GSM for very lightweight race-focused fabrics to around 190 GSM for more substantial performance tops. But GSM alone doesn't determine performance: the knit, breathability, moisture management and construction matter too.

With our Essential Tee, we aimed for a 'one and done' everyday running T-shirt. At 160 GSM, it's a mid-weight fabric designed to work just as well for the mindful miles as it does for the Saturday Parkrun.

4. T-shirt, vest or long sleeve?

There isn't one best type of running top. The right choice depends on the conditions and personal preference.

The T-shirt is the all-rounder. A good technical short-sleeve T-shirt works across a wide range of UK conditions and can be worn alone, over a base layer or under a running jacket.

Vests or singlets provide more ventilation and leave the arms and shoulders unrestricted. Some runners love them, some hate them, but they're particularly suited to hot weather and racing. Just pay attention to the fit around the arms and shoulders, which can become rubbing points over longer distances.

Long-sleeve tops obviously provide additional coverage and warmth and are particularly useful through autumn and winter, either alone or underneath a jacket. Or a figure hugging long-sleeved base layer allows you to keep a lot warmer when the chill factor hits.

The British weather being what it is, you'll probably eventually find a use for all types of top.

5. Fit matters

Some runners prefer a close athletic fit, while others prefer a looser T-shirt. Neither is inherently correct. What matters is how it feels while you're running, not standing in front of a mirror.

Does the top pull across your shoulders? Does the hem ride up? Is there excess material moving around your torso? Does the neckline feel restrictive?

This is also where stretch and sleeve construction can make a difference. Four-way stretch allows fabric to stretch both across its width and along its length, helping the top move naturally with your shoulders, arms and torso.

Sleeve construction matters too. Raglan sleeves use a diagonal seam extending towards the neckline, while set-in sleeves like in our Essential Tee join around the natural shoulder for a more structured T-shirt fit.

Neither is automatically better. A well-cut set-in sleeve combined with four-way stretch can provide excellent freedom of movement. What matters is that the garment moves with you without pulling, bunching or feeling restrictive.

Ultimately, the best running top is one you stop noticing once you start running.

6. Think about chafing before it happens

A top that feels perfectly comfortable during a five-minute try-on can become considerably less pleasant 15 miles into a long run.

When choosing a running top, look carefully at seams and labels, particularly around the underarms, shoulders and sides where there's repeated movement.

Labels are a tiny detail that can make a surprisingly big difference. A stiff or badly positioned label might be unnoticeable when you first put a top on, but repetitive movement can turn small irritations into big ones.

For the Essential Tee, we've gone completely label-free, using silicone-printed wash instructions to eliminate one potential source of the dreaded chafe.

7. Breathability and sweat management aren't quite the same thing

You'll often see running tops described as both breathable and moisture-wicking, but they're not exactly the same thing.

Breathability is broadly about allowing heat and moisture vapour to escape. Moisture management is about what happens to liquid sweat, ideally helping spread it through the fabric so it can evaporate rather than leaving saturated material against your skin.

The structure of a fabric can influence both, which is why two performance fabrics can feel very different when you're actually running in them.

Our Essential Tee is both breathable and moisture-wicking but has a closer weave than some running fabrics because this was the combination our testers preferred during product development.

So, what makes the best running top?

There's no single perfect running top for every runner, distance and condition.

Look for good-quality technical material, appropriate fabric weight, effective moisture management, a comfortable unrestricted fit and thoughtful construction that minimises potential rubbing.

Most importantly, don't judge performance by one specification. Maybe you prefer cotton for light jogs. Polyester doesn't automatically mean technical. Ultra-light doesn't automatically mean better. And a striking print doesn't automatically mean performance.

The real test is much simpler: Does it stay comfortable when I'm hot, sweaty, tired and miles from home?

Or, even simpler: Do I like how this feels when I run?

Because that's when a running top earns its place in your kit drawer.