A personal trainer shared the 2 popular fitness supplements that she would never take

• Personal trainer Hayley Madigan isn't against supplements but there are some common ones she avoids.
• Madigan told Business Insider why she doesn't use products including energy drinks and protein bars.
• There's no one-size-fits-all approach to taking supplements.

Personal trainer Hayley Madigan knows that certain supplements can help her feel and perform at her best.

But, there are others that Madigan, 34, would never take.

More than half of US adults take supplements, according to the American Medical Association, and the market is set to be worth about $308 billion worldwide by 2028, up from $191 billion in 2020, according to Statista.

But experts say that we should aim to get the nutrients our bodies need from food. While supplements, such as protein powders and creatine, may be particularly useful for those who are active like Madigan, not everyone needs to take them. And some can even leave us feeling worse than we did before. If you're not sure what supplements you might need, speak to your doctor.

Madigan, who's based in Portsmouth, UK, told Business Insider why she avoids products including energy drinks and pre-workout supplements.

Madigan avoids energy drinks and pre-workout supplements

It's not uncommon to see people going into the gym sipping energy and pre-workout drinks, but not everyone gets on well with them.

Madigan used to take pre-workout supplements, which are different to regular energy drinks because they also contain ingredients designed to increase workout performance, to boost her energy.

But Madigan said she steers clear of high-caffeine supplements like these as they tend to make her energy levels crash and make her feel anxious and unwell, she said.

"I found that I was crashing after the pre-workout had worn off and it had a tendency to make me feel more tired," Madigan said. "So now I train in the morning and tend to use my morning coffee instead of pre-workout."

Madigan is not the only personal trainer to have stopped taking pre-workout supplements. Celebrity trainer Luke Worthington previously told BI he made the same decision after realizing he was working out when he should have been resting.

Protein bars often contain artificial sweeteners

While protein bars can be a convenient way to eat more protein, they're often highly processed and contain various artificial ingredients. Research suggests that ultra-processed foods are linked to a range of health problems, including cardiovascular diseases, type 2 diabetes, cancer, and obesity. They can also have a more immediate negative effect on someone's health if they are sensitive to certain ingredients.

"I also don't have protein bars anymore as the artificial sweeteners in them were causing havoc with my stomach and digestion," Madigan said. "I prefer to add in more 'real food' as opposed to having too many artificial supplements throughout the day."

Studies suggest that eating too many artificial sweeteners can lead to gas and bloating, while research on rodents indicates that they could harm "good" gut bacteria.

Everyone is different

It may be tempting to try supplements we see others taking, but there's no one-size-fits-all approach, as each of us has different requirements.

Vitamin B12 helps keep our body's blood and nerve cells healthy. Madigan thought she might need to take a supplement if she wasn't getting enough through her diet (it's found in foods such as meat, fish, eggs, and dairy). But a blood test showed that she had naturally high levels, so she doesn't need to, she said.