saudigastro.com/patients/slimming-and-bodybuilding-supplements
This article is educational and does not replace your doctor's advice. Seek urgent care for any red-flag symptoms.
Drug class
Dietary supplements (often adulterated with undeclared drugs)
Examples
Herbal or “natural” slimming capsules and teas, fat burners, pre-workout powders, creatine, “prohormone” and anabolic products, laxative or diuretic “detox” teas and pills. Brand names are not listed because products change often and the safest rule is to avoid unregistered products.
How it works
Supplements are not tested like medicines before sale. Regulators in many countries, including the SFDA and the US FDA, have repeatedly found “herbal” slimming products secretly adulterated with prescription drugs. Sibutramine (an appetite suppressant withdrawn from many markets in 2010 because of heart attack and stroke risk), phenolphthalein (a laxative withdrawn because of cancer concerns), and drugs such as sildenafil-type agents, antidepressants and steroids have all been found. SFDA public warnings have named several slimming products found to contain sibutramine. Hidden ingredients explain both the apparent “results” and the harm. Other risks: stimulants (high-dose caffeine, synephrine, DMAA, ephedra-type compounds) cause palpitations, high blood pressure and, rarely, death; 2,4-dinitrophenol (DNP) is a toxic industrial chemical that has caused fatal overheating; some “fat burner” products (for example the OxyElite Pro outbreak) caused acute liver failure. Anabolic-androgenic steroids and SARMs (selective androgen receptor modulators, unapproved “muscle” drugs) can cause cholestatic jaundice, blood-filled liver cysts (peliosis hepatis), liver tumours, heart and cholesterol problems, lower sperm count, testicular shrinkage and mood changes. Creatine, in contrast, is one of the best-studied sports supplements: the International Society of Sports Nutrition position stand (2017) considers it safe for healthy adults, but it can raise the blood creatinine reading (a kidney test) without kidney damage, which confuses test results, and it should be avoided or discussed in kidney disease. Pre-workout powders typically combine caffeine and other stimulants. Laxative and diuretic misuse for weight loss causes dehydration, low potassium and other salts, kidney injury and a dependent, sluggish bowel; it is a form of disordered eating that needs support.
What it treats
- No slimming or fat-burning supplement has good evidence of safe, lasting weight loss; evidence-based options are diet, activity, behaviour support and, where appropriate, prescribed medicines or surgery (see our article on GLP-1 and weight-loss drugs)
- Creatine: GOOD evidence for modest gains in strength and lean mass with resistance training in healthy adults; not needed for general health
- Caffeine and pre-workout stimulants: GOOD evidence for short-term performance, with real heart and sleep risks at high amounts
- Anabolic steroids, prohormones and SARMs: NO safe use as a supplement; steroids are prescription drugs for specific medical conditions
- Laxative and diuretic “detox” for weight: NONE for fat loss; they lose water, not fat, and are harmful when misused
How to take it
The safest advice is to avoid slimming, fat-burning, “prohormone” and “detox” products. If you are an adult who chooses a sports supplement such as creatine or caffeine: speak to your doctor or pharmacist first, follow the label and your doctor’s or pharmacist’s advice, buy only SFDA-registered products from licensed pharmacies, avoid products with long ingredient lists, “proprietary blends” or promises of fast results, and drink enough water. Choose products with independent third-party testing marks where available. Never buy steroids or injections from gyms, social media or unlicensed sellers. If you are under 18, avoid these supplements. If you feel you must use laxatives, diuretics or diet pills to control weight, or are preoccupied with food and body shape, please speak to your doctor; this is treatable.
Common side effects
- Palpitations, jitteriness, anxiety, trouble sleeping (stimulants and caffeine)
- Stomach pain, diarrhoea, nausea, bloating (creatine, laxatives, many blends)
- Headache, flushing, increased sweating
- Acne, hair loss, mood swings (anabolic products)
- Weight gain from water with creatine
Serious side effects — call your doctor
Chest pain, fast or irregular heartbeat, fainting, severe headache, or sudden weakness or speech trouble
Stimulant or hidden-drug toxicity can cause heart attack, arrhythmia or stroke. Call emergency services now.
Yellow eyes or skin, dark urine, pale stools, severe itching, nausea or upper right belly pain
Possible liver injury (anabolic steroids, SARMs, fat burners and herbal blends are well-known causes). Stop the product and see a doctor urgently; bring the product.
Very high body temperature, heavy sweating, rapid breathing, confusion or collapse
A medical emergency (for example DNP or stimulant overheating). Call emergency services now.
Muscle cramps, weakness, palpitations, dizziness, very little urine, or fainting after laxatives or diuretics
Dehydration and low potassium or sodium can disturb the heart and kidneys. Go to the emergency department.
Severe belly pain, vomiting blood, black stools, or bloody diarrhoea
May show gut bleeding or serious bowel injury. Go to the emergency department now.
Low mood, thoughts of self-harm, or intense fear of weight gain with restricting, purging or laxative use
These need compassionate medical and psychological help. Speak to your doctor; call emergency services if you are in danger.
Interactions
Hidden drugs (for example sibutramine, antidepressants, steroids, sildenafil-type drugs) can interact dangerously with prescribed medicines, including antidepressants, heart and blood-pressure drugs and nitrates, and can be unsafe in heart disease, glaucoma, pregnancy and epilepsy. Stimulants combined with caffeine, decongestants or ADHD medicines raise heart risks. Creatine and diuretics or NSAIDs may add to kidney strain, and creatine raises blood creatinine; tell the doctor who orders kidney tests. Anabolic steroids and alcohol or herbal products add to liver injury risk. Laxative misuse can cause low potassium, which interacts with digoxin and heart-rhythm medicines. Always tell your doctor and pharmacist about every supplement, and show the label.
Monitoring
If you have used any of these products, especially anabolic or unregistered products, ask your doctor about liver tests, kidney function, blood pressure, cholesterol, blood salts (potassium) and hormone checks. Bring the product so staff can check ingredients. Tell the team if you are about to have an endoscopy or surgery.
When and how to stop
Stop immediately if you develop any red-flag symptom. After stopping steroids or stimulants, do not restart. Do not stop prescribed medicines for your heart or other conditions because of a supplement; speak to your doctor. If you are dependent on laxatives, ask for a supervised plan rather than stopping suddenly.
Pregnancy & breastfeeding
Slimming, fat-burning, pre-workout, anabolic and “detox” products should not be used in pregnancy or breastfeeding. Hidden drugs and high-dose stimulants can harm the baby. Speak to your doctor about safe weight management.
In the Saudi context
Slimming and muscle-building products are widely marketed in gyms, on social media and online in Saudi Arabia. The SFDA publishes safety warnings and recalls on its website (for example for slimming products found to contain sibutramine), so check them, and check that a product is registered. Also be careful of unregistered weight-loss injections, which can be counterfeit (WHO has issued alerts about falsified semaglutide). HOW TO REPORT: tell the SFDA National Pharmacovigilance Centre about any suspected side effect or suspicious product, through the SFDA website or the SFDA unified contact number 19999 (the number listed in SFDA warnings; check the website for current details); your doctor or pharmacist can report for you. Keep the product and packaging. Do not use fasting during Ramadan together with fat burners or diuretics, because dehydration risks rise.
Questions to ask your doctor
Save this list or print it before your appointment — doctors appreciate prepared patients.
- Is the product I take registered with the SFDA, and could it contain hidden drugs?
- Do I need liver, kidney or heart tests because of what I have taken?
- What is a safe, evidence-based plan for losing weight or building muscle for me?
- Is creatine safe given my kidneys, and will it change my kidney blood tests?
- How do I report a suspected harmful product?
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Status: Approved for publication by SGA; individual clinician review is ongoing · Published 24/04/2026
For general education only; it does not replace your doctor’s advice. Individual clinician review of this guide is ongoing. SGA clinician? Review this guide