Are training and performance gummies bad for you?

For most healthy adults, training and performance gummies are not harmful when you take them as the label tells you to. What decides the risk is not the gummy format. It is three concrete things: the active ingredient, the dose per serving, and the person taking them. A gummy with 5 g of creatine, one with 44 mg of caffeine from guarana and another with 2.5 g of L-carnitine are not the same thing — not in their effects, and not in their precautions.

The legitimate worries sit on a different plane: interactions with medicines, pre-existing health conditions (especially kidney and heart conditions), pregnancy and breastfeeding, and the fact that gummies are easy to eat by the handful. This article separates what the evidence shows from what is just generic fear, with concrete doses and comparisons against the labels on the products in the range.

What does "harmful" actually mean? It depends on the dose and on the person

In toxicology, the line between safe and dangerous is almost always a question of quantity. With caffeine, for instance, the reference review on the subject describes moderate consumption as safe and approved as a food ingredient within certain limits, but stresses that the negative effects of excessive consumption must be considered, especially in children and pregnant women. With creatine, the position of the International Society of Sports Nutrition concludes that supplementation is safe in the short and long term at the recommended doses.

That does not mean more is better. The review by Antonio and colleagues, which answers 12 common misconceptions about creatine, indicates that supplementation is relatively well tolerated, especially at the recommended doses of 3–5 g a day or 0.1 g/kg of body mass a day. Above that, the body does not make more use of it — and the risk of discomfort goes up.

Gummies add one more factor: the sweet taste and the chewy texture make it easy to go back for more. Taking the stated serving is one thing; eating half the jar because it tastes good is another, and that is where the dose stops being the one on the label.

Two thresholds are worth keeping apart. There is the tolerable upper level — the amount below which almost nobody feels negative effects — and there is the dangerous dose, the one that can cause serious harm. There is a considerable margin between them, but that does not mean it should be tested. With caffeine, for example, 400 mg a day is considered safe for healthy adults, while 10 grams can be fatal. With creatine, normal doses are well tolerated, but very high doses may put a strain on the kidneys in sensitive people.

Mild, common side effects: what to expect

When symptoms do appear, they are usually mild and pass. They depend on the ingredient:

• Gastrointestinal discomfort — the review by Poortmans and Francaux on the adverse effects of creatine mentions gastrointestinal disturbances and occasional muscle cramps in healthy individuals, though these are anecdotal.
• Stimulation, a racing heart or difficulty getting to sleep — plausible with gummies that contain guarana or caffeine, especially if you take them late in the day.
• Headache or mild dizziness — usually settles with hydration and rest.

If you feel any of these, stop taking them, drink water and watch how you feel. If they are intense, persistent or getting worse, speak to a healthcare professional.

What the evidence says about each ingredient in the range

Creatine: one of the most studied supplements there is

Creatine is probably the ingredient in this category with the most scientific support behind it. The review by Wax and colleagues, on creatine for exercise and performance in healthy populations, concludes that supplementation consistently raises the intracellular creatine pool and has positive ergogenic effects in short, high-intensity efforts, including increases in maximal strength, power and sprint performance, and may speed recovery between efforts.

In adults under 50, a meta-analysis of 23 studies that combined creatine with resistance training found significant strength gains in the upper body (weighted mean difference 4.43 kg) and the lower body (11.35 kg) compared with placebo. In a meta-analysis of 10 studies using direct imaging of hypertrophy, the extra effect of creatine on top of resistance training on muscle thickness was small, in the order of 0.10–0.16 cm. In other words: the effect on strength is more robust than the effect on muscle mass as measured by imaging.

On safety, the ISSN position considers creatine safe in the short and long term at the recommended doses, and the review by Antonio and colleagues dismantles frequent misconceptions, including the idea that creatine causes water retention, is an anabolic steroid, causes kidney damage, hair loss, dehydration or cramps.

Creatine Gummies provide 5000 mg (5 g) of creatine monohydrate per serving of 3 gummies, plus 50 µg of vitamin B12 (2000% NRV). Creatine trials typically use 3–5 g a day for maintenance or loading protocols of 20 g a day for a few days — as in the trial by Gordon and colleagues, which used 20 g a day in 4 doses of 5 g in 39 active women across the menstrual cycle. Study doses are not dosing instructions: always follow the label.

Guarana: caffeine with other compounds attached

Guarana matters mostly for the caffeine it contains. A meta-analysis of 8 placebo-controlled studies with 328 participants assessed the acute effect of guarana on cognition: the overall effect was less than trivial, but there was a small and significant effect on response time (g = 0.202), with no effect on accuracy.

In exercise, a double-blind crossover trial with 11 cyclists and non-cyclists trained in endurance compared 100 mg of caffeine, 500 mg of guarana (with 130 mg of caffeine) and placebo before 60 minutes of fixed-load cycling plus a 15-minute time trial. Work accumulated in the time trial was greater with guarana than with placebo, but low-dose caffeine on its own did not differ from either. In another trial, with 27 under-17 footballers, acute intake of 3 g of guarana seed powder did not improve jumping, sprinting or agility, but did increase the distance covered in the Yo-Yo intermittent test.

Energy Gummies with Guarana provide 200 mg of guarana extract per serving of 2 gummies, of which 44 mg is caffeine, plus 200 mg of L-theanine, 100 mg of L-tyrosine, vitamin B6 (1.4 mg, 100% NRV), vitamin B12 (10 µg, 400% NRV) and vitamin C (40 mg, 50% NRV). The label warns that they are not recommended for children, pregnant or breastfeeding women because of the caffeine. Vitamin B6 contributes to normal energy-yielding metabolism and vitamin C contributes to the normal functioning of the immune system.

L-carnitine: mixed evidence for performance

L-carnitine has been studied mainly for its role in fatty acid metabolism. A systematic review of 11 studies in healthy humans, with oral doses of 1 to 4 g a day for 12 or 24 weeks, concluded that supplementation combined with carbohydrates raised total carnitine content in skeletal muscle, but the effects on performance were variable.

A systematic review of 11 studies on oral L-carnitine and performance concluded that results depend on exercise intensity and that the effective doses and the best timing of intake are not yet well established. In a randomised, double-blind crossover trial with 20 recreational CrossFit practitioners, 3 g of L-carnitine tartrate taken 90 minutes before training did not improve the number of repetitions in the "Cindy" protocol.

L-Carnitine Gummies provide 2500 mg of L-carnitine per serving of 2 gummies. In a systematic review of 11 studies in healthy adults, the oral doses studied ranged from 1 to 4 g a day, for 12 or 24 weeks. The label dose is the one to follow, and study doses are not dosing instructions.

Side by side: what sets the three gummies apart

Product	Main active per serving	Serving	Specific label precaution
Creatine Gummies	5000 mg creatine monohydrate + 50 µg vitamin B12	3 gummies	Contains polyols; excessive consumption may have a laxative effect
Energy Gummies with Guarana	200 mg guarana extract (44 mg caffeine) + 200 mg L-theanine + 100 mg L-tyrosine + vitamins B6, B12 and C	2 gummies	Contains caffeine; not recommended for children, pregnant or breastfeeding women
L-Carnitine Gummies	2500 mg L-carnitine	2 gummies	In case of pregnancy, breastfeeding, illness or use of medication, consult a healthcare professional

None of these products is a medicine and none promises to treat or prevent illness. They are food supplements, and their role is to complement — not replace — a varied and balanced diet.

Who should talk to a healthcare professional before taking them

There are situations where the decision stops being trivial:

• Pregnant or breastfeeding — the safety of several ingredients is not established in this group. Guarana, because of the caffeine, is not recommended.
• People with kidney or liver disease — the metabolism and clearance of the compounds may be altered.
• People with high blood pressure or heart problems — stimulants such as caffeine may change blood pressure and heart rhythm.
• Anyone on regular medication — there are possible interactions, described below.
• Children and adolescents — there is not enough data on long-term safety, and guarana is explicitly advised against on the label.

One further group deserves a mention: people with diabetes. The polyols used as sweeteners in the gummies may have a reduced impact on blood glucose, but it is worth checking the label and speaking to the healthcare professional who manages your glucose control before making these gummies part of your routine.

If you are in any of these situations, speak to your doctor or pharmacist before you start. If you want to go further, see the articles on creatine and safety and on guarana and who should avoid it.

Drug interactions: what the evidence suggests

Supplements can interact with medicines. The most relevant interactions in this category are:

• Caffeine (from guarana) with other stimulants or certain medicines — the review by Heckman and colleagues on caffeine in foods stresses that the negative effects of excessive consumption must be considered, especially in sensitive populations. If you take medicines that raise heart rate or blood pressure, speak to your doctor.
• Creatine with nephrotoxic medicines or diuretics — the ISSN position considers creatine safe at the recommended doses, but recommends caution in people with kidney disease or those taking medicines that affect the kidneys.
• L-carnitine and anticoagulants — the review by Sawicka and colleagues mentions metabolic changes with prolonged supplementation, including a rise in fasting TMAO, and recommends monitoring in specific populations.

Do not assume that "it's natural, so it can't interact". Always take the list of supplements you use to your appointment.

Red flags: when to stop and get help

Most effects are mild, but there are signs that need medical assessment straight away:

• Strong palpitations, chest pain or shortness of breath.
• Fainting, or feeling as though you are about to faint.
• Persistent vomiting or diarrhoea with blood in it.
• Swelling of the face, lips or tongue — a possible allergic reaction.
• Very dark urine or a marked drop in how much you urinate.

In these cases, do not wait for it to pass. Contact a healthcare professional or, if it is serious, the emergency services.

What the gummy format changes — and what it doesn't

A gummy is not intrinsically worse than a tablet, but it has its own characteristics. First, the polyols: the labels on Creatine Gummies, L-Carnitine Gummies and Energy Gummies warn that they contain polyols and that excessive consumption may have a laxative effect. Second, the chewing: gummies can stick to the teeth, so cleaning your teeth afterwards is a reasonable precaution. Third, and most important, the accessibility: gummies look like sweets and are appealing to children. Keep the jars out of reach of little ones.

If a child eats several caffeine-containing gummies by mistake, do not wait to see what happens: contact a healthcare professional, your pharmacist or the poisons information centre immediately. Keep the jars somewhere safe, ideally locked away.

On comparative effectiveness between gummies and tablets, the honest answer is that there are no trials directly comparing the two formats for these ingredients. What is known is that creatine monohydrate is effective by mouth and that the label dose is what ensures you are taking the amount intended. If you have trouble swallowing tablets, the gummy is a practical alternative; if you want the format with the most direct evidence, creatine monohydrate powder is the most studied. You can read more in the article on creatine in gummy or tablet form.

Myths and what the evidence actually supports

A few claims about this category circulate widely enough to be worth addressing head-on.

"Creatine damages the kidneys." This is one of the misconceptions the review by Antonio and colleagues specifically addresses. In healthy people, at recommended doses, the evidence does not support it. In people with existing kidney disease, caution is warranted — which is a different statement.

"Creatine is a steroid." It is not. Creatine is a compound found naturally in muscle and in foods such as meat and fish, and it works through a different mechanism entirely.

"Guarana gives you clean energy without the caffeine effects." Guarana's effects are largely caffeine effects. The label on Energy Gummies with Guarana states 44 mg of caffeine per daily dose and warns against use in children, pregnancy and breastfeeding. The meta-analysis on cognition found an overall effect below trivial, with a small effect on response time only.

"L-carnitine burns fat during exercise." The evidence is more modest than the marketing. The systematic reviews point to variable effects on performance and note that effective doses and timing are not well established.

"If it's a gummy, it's basically a sweet." The format does not determine the dose. What matters is the declared amount per serving, which is why reading the label matters more than the shape of the product.

None of this means these products will do anything for you personally. It means the claims made about them should be judged against what the studies actually measured.

What is still not known

Some gaps are worth acknowledging. Most trials with these ingredients run for weeks to months, so the effects of daily use over years are not well characterised for every formulation. Clinical trials tend to exclude people with illnesses, which limits what is known about populations with comorbidities. And comparative bioavailability between formats (gummy, tablet, powder) is not established for every ingredient. When there is no clear answer, the right approach is not to invent certainties.

How to use them sensibly

If you decide to include training and performance gummies in your routine, the essentials are simple: read the label, stick to the stated serving, do not combine several caffeine-containing products on the same day without counting the total, and speak to a healthcare professional if you have any condition or take medication. For background on the ingredients, see how creatine works, how guarana works and how L-carnitine works. Supplements complement — they do not replace — a varied diet, adequate sleep and a well-structured training plan.

To go deeper into the daily dose of each ingredient and how to read the label, see creatine: daily dose and guarana: daily dose and label.