The myth of sports supplements revealed - and which ones can do you more harm than good: From smelling salts to caffeine gels, we lift the lid on them all, including the substances rugby players swear by but are banned in the NFL

Step into most professional rugby dressing rooms and there will be a table that looks like a pick-and-mix for grown-ups. Smelling salts, caffeine gels, processed sugars. All entirely legal, mixed in science labs by boffins tasked with finding a competitive edge.

Most players do not think twice about using them. The best athletes will do whatever they can to find a competitive edge. The relentless drive to win. As Kyle Sinckler says: ‘You’re paid to get results.’ But at what cost?

As new products are rolled out, professional athletes become guinea pigs to prove their effectiveness at the sharp end of sport. However, there is scepticism and uncertainty around the long-term health implications.

Some academics fear smelling salts could mask the signs of concussion. Processed gels have impacts on heart and gut health and one ex-coach asks: ‘What’s the cost of immediate performance improvement over time?’

Moments before the Lions left the dressing room for their first Test in Australia this summer, Tadhg Beirne pulled out a pot of smelling salts so potent his team-mates physically recoiled. His eyes bulged as he took a couple of whiffs. Bar a few involuntary flinches, no one in the huddle batted an eyelid.

It was broadcast to the breakfast television audience back home through the live changing-room camera. Anyone who fancied following in his footsteps could do a quick Google search and find products such as Hell Fire, Doom Inhaler and Bone Rush available for less than £15.

Professional rugby players like Ellis Genge are turning to smelling salts for a competitive edge

Tadhg Beirne was captured taking a whiff of the intense ammonia before the Lions' first Test  

Smelling salts are legal and widely available through most team medical staff. Historically, they were used to bring soldiers back to consciousness. They trigger an involuntary intake of breath that delivers a sudden hit of oxygen to the brain. In the world of sport it is a means of sharpening the mind for Trojan combat.

‘They’d be on the tables as you were about to go out,’ explains former Wales fly-half Dan Biggar. ‘It’s not something hidden away. The whole point is to really wake you up. A bit of a hit. It’s such a strong smell that it focuses you.

‘I’d take it when I needed a pick-me-up. There were loads of different types. Some really strong, some milder. Some boys sniff it right up their nostrils and others waft it underneath their nose.’

The use of products such as smelling salts has been widely accepted in rugby — even distributed by school coaches — but there is a growing apprehension about the long-term effects.

Smelling salts are forbidden in most boxing competitions and NFL teams have been banned from distributing them this season following safety concerns, although players are still free to source their own. 

The competition has been on red alert since they had to pay a $1billion settlement in 2015 for a class-action head-trauma case. The NFL’s head, neck and spine committee, chaired by Dr Nicholas Theodore, approved the move after safety warnings were issued by America’s Food and Drug Administration (FDA) about shortness of breath, seizures, migraines, vomiting, diarrhoea and fainting.

Dr Theodore, professor and chairman of neurosurgery at the University of Arizona College of Medicine, has held talks with chief medical staff at World Rugby and outlined to Daily Mail Sport why rugby should take similar action.

‘Our FDA has warned against energy-boosting inhalants,’ he says. ‘They talked about seizures in some patients, migraines, headaches. It’s not risk-free at all and there’s no proven benefit. Unfiltered ammonia can potentially cause lung damage, too.

NFL teams have now been banned from distributing smelling salts as they could mask strong concussions in athletes keen to play on

‘There’s stuff out there rooted in Harry Potter witchcraft. At some point, weightlifting and contact sports created this folklore that you sniff these things before a big play. It’s really a chemical irritant. It doesn’t do anything physiologically that’s going to help you.

‘There was a concern it could mask the signs of concussion. You take a smell and say, “Yeah, I’m OK”. It’s theoretical but something we have to take into consideration. There’s no study because you’re not going to line up a bunch of guys, give them ammonia, then hit their heads and see if it has masked concussion.

‘The issue is the optics with kids. If you see someone doing this in rugby, the kids will want to do this, too. It’s a bad message.’

Smelling salts and food-based drugs are on hand to professional athletes. Most sportspeople are unaware of the science behind the products but have a tendency to follow the common practice. Daily Mail Sport understands a number of professional rugby players stopped using many supplements due to the uncertainty around long-term effects.

‘When I needed a bit of a kick before a match I thought, “F*** it, I’ll use the sniffing salts” and I couldn’t see out my eyes for 30 seconds,’ says former England prop Joe Marler. ‘I was bang into them. The older I got, the more reliant I was on caffeine gum.

‘It was more mental than physical. There were boys that would be sick but I didn’t know if it was the caffeine or nerves. You’d do whatever you could to get out on the pitch. After games I’d be up all night because I’d had 10 times the recommended caffeine level.’

The recommended daily intake of caffeine, a stimulant that increases alertness in the brain, is 400 milligrams — around four cups of coffee. Players have been known to take sleeping tablets to offset the effects of caffeine gels.

Some Premier League football clubs are understood to be moving away from processed performance supplements.

Kyle Sinckler has been open about a caffeine addiction after consuming rugby nutraceuticals 

Former England Rugby strength and conditioning coach Tom Tombleson is among the sceptics. ‘Anything that has an extreme result usually has an extreme reaction somewhere else,’ he tells Daily Mail Sport. ‘Smelling salts give you a sensory wake-up. If you’re distracted with pain or anxiety, or you feel a bit flat, it’s like having an electric shock. I took a smell of one once and it was like I’d been punched in the face. There will be a pathway somewhere disrupted.

‘Everyone’s so used to coffee and caffeine so you look for something else to give you a hit. You’d see players going to the toilet, throwing up or having diarrhoea because they’re over-caffeinated.

‘People have used sugar. They’ve used bicarbonate to dull lactic acid accumulation which can stem fatigue. They’ve used caffeine, guarana, ginseng… all these things you can get off the shelf.

‘It’s not healthy. Sports drinks aren’t healthy. Professional athletes are putting these things in their stomachs for 15 years. They’re terrible for teeth and gut health but people throw them down their neck as they’re free.’

England and Toulon prop Sinckler told Daily Mail Sport he became reliant on caffeine early in his career. He weaned himself off it when he moved to France and experienced withdrawal symptoms. In his early 20s he had heart palpitations and only recently realised it was caused by being over-caffeinated.

‘As a young player, you don’t really know what you’re doing,’ says Sinckler, who discussed caffeine intake on his latest Cor Counsel podcast. ‘I’d follow the older players. If they did something, I’d try it. I consumed a lot of caffeine because I saw everyone else doing it.

‘I started drinking lots of coffee and then you see the caffeine gels and the pre-workouts and you think, “I’ll give that a go”. By the time you blink, you’re reliant on that stimulus. It’s a slippery slope. Once reliant on it, you need more to get that stimulus.

‘I’ve got an enlarged heart and an irregular heartbeat, which is totally normal for a black athlete. I didn’t realise the effect over-consumption of caffeine would have on my heart. After a game I would be knackered but totally wired in, struggling to sleep with really weird heart palpitations.’

He adds: ‘Some guys might sniff smelling salts, some guys might have a Red Bull, some might have a caffeine gel. In that moment you’re not thinking, “OK, 10 years down the line this might have that effect on the day”. You’re a professional athlete and you’re paid to get results.’

There is, of course, detailed sports science that proves short-term performance boosts for most over-the-counter products. Smelling salts, however, are not one of those products, despite their popularity among athletes.

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‘Performance increases aren’t in tandem with long-term health,’ adds Tombleson. ‘It’s like eating packets of crisps every day, those ultra-processed foods lead to health complications later on. Those sweet protein bars you can buy on the way back from the gym are terrible. They’re a substitute for a Mars bar. Highly processed with loads of ingredients manufactured in a laboratory.

‘In rugby, anti-inflammatories are given out like Smarties. There’s long-term issues around gut health with that stuff. There should be a duty of care. You tend to see teams giving them other things to compensate for it. A probiotic supplement to manage gut health and compensate for them taking that other stuff. To neutralise it. None of these are banned substances but it doesn’t mean it’s healthy long-term.’

Rugby and other sports are deeply embedded into the culture of legal enhancements. That is unlikely to change any time soon. But the warning is out there, loud and clear — players should think twice about what they are taking and the long-term effects.