At first, a 24-year-old software engineer walked into our emergency looking more exhausted than ill. His family was worried as he was passing cola-coloured urine. His muscle was sore, he felt nauseous and disoriented. Little did he or we realise till we ran tests that his kidney function was severely affected. He needed immediate dialysis and IV fluids to clear his body of waste and toxins that could have otherwise led to sepsis.This young man was a regular at the gym and like many professionals balancing desk jobs with fitness goals, he wanted faster, more visible results. In the process he blindly trusted his gym instructor, who led him with protein and supplement powders. He had two to three scoops of whey protein powder daily, five grams of energy-giving creatine and an equal amount of collagen powder for joint health. Over and above everything, he had a protein-rich diet, with an overall protein intake close to 150 grams per day, way more than what his body could handle. Most of these supplements were inexpensive, locally sourced brands with unclear labelling.Encouraged by early gains, he intensified his workouts simultaneously. He gained 3 kg in a month, which he interpreted as proof of rapid muscle gain. Then came the warning signs — dark, cola-coloured urine, unrelenting fatigue and persistent muscle soreness. He ignored them and continued training and supplementing his diet. At the end of four weeks of dark urine and fatigue, his body collapsed and his kidneys got damaged.How supplement overdose injured kidneysThe young man’s levels of creatinine, a waste product that a healthy kidney flushes out, had risen to 3.2 mg/dL (0.7 to 1.3 mg/dL for adult men), signalling acute kidney injury. Creatine phosphokinase (CPK), an enzyme that indicates muscle damage and breakdown, had surged to 12,000 U/L (normal range is 20 and 200 U/L). Myoglobin — a toxic muscle protein released when fibres disintegrate — was spilling into his urine. Liver enzymes were elevated. His kidney function was failing.His trigger was a dangerous cluster — excessive creatine intake, very high protein consumption, punishing workout intensity and inadequate hydration. Physicians also suspected something more troubling: possible adulterants in the supplement powders. Worst of all, he trusted gym advisories and never cross-checked with a doctor.The protein paradoxProtein is indispensable for muscle repair but the belief that more protein automatically means more muscle is physiologically flawed. The body has limits to how much it can use effectively. Beyond that threshold, excess protein becomes metabolic waste that the kidneys must filter.Sports nutrition research generally supports protein intake in the range of about 1.2 to 2.0 grams per kg of body weight for athletes, 0.8 grams per kg of body weight for normal people. Intakes above 2 to 3 grams per kg body weight, which is common among gym enthusiasts, can impose unnecessary load on the kidneys, particularly when hydration is inadequate. Over time, persistently high filtration demand may stretch kidney function.Story continues below this adGastrointestinal distress is another frequent consequence. Concentrated protein supplements can trigger bloating, acidity, gastritis and reflux, particularly when consumed in multiple large shakes rather than distributed through whole foods.Creatine: How much is too muchCreatine supplements are safe when used correctly. But safety depends heavily on dose, hydration status and training context. Creatine increases intracellular water retention in muscle tissue. This can produce rapid weight gain but also raise fluid requirements. Without adequate hydration, users may experience muscle cramps, gastrointestinal upset and electrolyte imbalance. When intense exercise is layered on top of dehydration, the risk of concentrated, cola-like urine rises sharply.That’s because of rhabdomyolysis, a condition when overworked muscle fibres rupture and release the protein myoglobin into the bloodstream. Myoglobin can obstruct kidney filtration structures, precipitating acute kidney injury. Overtraining without supervision further magnifies the danger.How safe are collagen supplementsCollagen powders are marketed as gentle enhancers of joint and skin health, often perceived as harmless add-ons. Yet these supplements operate in a largely unregulated space. Formulations vary widely. Some products contain excessive calcium. Others include flavouring agents, preservatives and filler compounds that may irritate the gastrointestinal tract. Reports of contamination with heavy metals have raised additional safety concerns. Emerging clinical observations also suggest that chronic exposure to certain contaminants may disrupt hormonal balance.Story continues below this adFor young adults consuming balanced diets, routine collagen supplementation is rarely essential.The compounding effect of supplement stackingTaken individually, whey protein, creatine and collagen may appear manageable. Combined without supervision, they create cumulative metabolic stress. High protein intake increases waste processing. Creatine alters fluid distribution within muscles. Intense training accelerates muscle fibre breakdown. Dehydration reduces the kidneys’ ability to clear toxins. Together, these factors can overwhelm organs designed for balance, not an overload.Ignoring early warning signs like fatigue, dark urine, persistent soreness allows reversible stress to escalate into emergency.What appears to be a harmless scoop can function like an unprescribed drug. Supplements are not shortcuts. Used wisely, they can support training. Used blindly, they can destabilise vital organs.(Dr Tickoo is Director, Internal Medicine, Max Healthcare)