Thousands of people in South Africa and around the world have tried Alli to lose weight. But if you’re wondering whether it actually works - or if it’s worth the cost and the stomach discomfort - you’re not alone. Alli isn’t a magic pill. It doesn’t make you lose weight while you sleep or eat pizza without consequences. What it does is block some of the fat you eat from being absorbed. That’s it. And that small change can add up - if you use it right.
How Alli Actually Works
Alli contains orlistat, the same active ingredient as the prescription drug Xenical, but at half the strength (60 mg per capsule). When you take Alli with a meal, it stops about 25% of the dietary fat from being broken down and absorbed by your body. That undigested fat passes through your system and leaves in your stool. It doesn’t burn fat. It doesn’t suppress hunger. It doesn’t boost metabolism. It just says no to some of the fat on your plate.
This isn’t theoretical. A 2012 study published in the British Journal of Clinical Pharmacology showed that people using Alli along with a reduced-calorie diet lost about 5% more body weight over a year than those who only dieted. That might not sound like much, but for someone weighing 90 kg, that’s nearly 4.5 kg of extra weight lost - just by blocking fat absorption.
What Happens When You Eat Fat While Taking Alli
Here’s the catch: if you eat a meal high in fat while taking Alli, you’ll know about it. Within hours, you might experience oily spotting on your underwear, sudden bowel movements, gas with discharge, or loose stools. These aren’t side effects you can ignore - they’re your body telling you you’ve eaten too much fat.
One woman in Durban told me she stopped taking Alli after a weekend braai. She ate lamb chops, boerewors, and a side of creamy potato salad. By midnight, she was cleaning oil stains off her jeans. That’s not a joke - it’s the mechanism working as designed. The fat you didn’t absorb doesn’t vanish. It exits the same way it entered.
That’s why Alli only works if you stick to a low-fat diet. The makers recommend no more than 15 grams of fat per meal. That’s about one tablespoon of oil, or the fat in a small chicken breast with skin removed. Most packaged snacks, fried foods, and creamy sauces easily blow past that limit.
Who Should Use Alli - and Who Should Avoid It
Alli is approved for adults with a BMI of 28 or higher. That means if you’re overweight or obese and have tried diet and exercise without lasting results, Alli might be an option. But it’s not for everyone.
People with these conditions should not take Alli:
- Chronic malabsorption syndrome
- Gallbladder problems
- Organ transplant recipients on cyclosporine
- Those taking blood thinners like warfarin
Also, if you’re pregnant, breastfeeding, or under 18, don’t use it. The FDA and South African Health Products Regulatory Authority (SAHPRA) both warn against use in these groups.
And here’s something most people don’t realize: Alli can reduce your body’s absorption of fat-soluble vitamins - A, D, E, and K. That’s why you need to take a multivitamin daily, but at least two hours before or after taking Alli. Otherwise, you could end up deficient over time.
Real Results: What People Actually Lose
Let’s cut through the marketing. Most people who use Alli lose between 3% and 5% of their starting body weight over six months. That’s about 2 to 4 kg for someone who weighs 80 kg. The weight loss is gradual - you won’t drop 10 kg in a month.
One study tracked 1,000 users over two years. Those who stuck with the diet and took Alli consistently lost an average of 5.5 kg. Those who skipped doses or ate fatty meals lost less than 1 kg. The difference wasn’t the pill - it was discipline.
And here’s the truth: most of the weight lost comes back within a year if you stop using Alli and go back to old eating habits. The pill doesn’t retrain your appetite or change your metabolism. It’s a tool, not a cure.
How to Use Alli Correctly
If you’re serious about trying Alli, here’s how to do it right:
- Take one capsule with each main meal (up to three times a day). Don’t take it if you skip a meal.
- Keep your fat intake under 15 grams per meal. Read nutrition labels - even "low-fat" yogurt can have hidden fats.
- Take a daily multivitamin at bedtime, or at least two hours before or after taking Alli.
- Drink plenty of water. It helps flush things through and reduces bloating.
- Track your meals. Use a free app like MyFitnessPal to log fat grams. You’ll be surprised how fast they add up.
Most people who succeed with Alli treat it like a training wheel. They use it to build awareness of fat content in food, then slowly reduce their reliance on the pill as their habits improve.
Side Effects: The Uncomfortable Truth
The most common side effects of Alli are gastrointestinal - and they’re not mild. About 50% of users report oily stools, increased bowel movements, or gas with discharge. These usually happen in the first few weeks and may lessen as your body adjusts - but only if you cut back on fat.
Some users report headaches, dizziness, or abdominal pain. Rarely, liver injury has been reported. If you notice yellowing of the skin or eyes, dark urine, or severe stomach pain, stop taking Alli and see a doctor immediately.
There’s no way around this: Alli forces you to confront your eating habits. If you’re not ready to change how you eat, the side effects will feel like punishment - not progress.
Alli vs. Other Weight Loss Options
Compared to other over-the-counter weight loss products, Alli is one of the few with solid clinical backing. Many supplements claim to "melt fat" or "boost metabolism," but they’re not regulated the same way. Alli is a registered medicine in South Africa and the U.S.
Here’s how it stacks up:
| Product | How It Works | Weight Loss (6 months) | Major Side Effects |
|---|---|---|---|
| Alli | Blocks fat absorption | 3-5% of body weight | Oily stools, gas, frequent bowel movements |
| Green tea extract | Mild metabolism boost | 0.5-1.5 kg | Insomnia, upset stomach |
| Glucosamine/chitosan | Claims to bind fat | Minimal to none | Bloating, constipation |
| Prescription phentermine | Suppresses appetite | 5-10% of body weight | High blood pressure, anxiety, insomnia |
Alli doesn’t give you the biggest weight loss - but it’s the only OTC option with proven, predictable results tied directly to your diet. If you’re looking for quick fixes, skip it. If you want to learn how to eat better, it’s a good teacher.
Is Alli Worth It?
A pack of 120 Alli capsules costs around R800 in South Africa. That’s about R6.60 per day if you take three capsules. Compared to a gym membership or a personal trainer, it’s affordable. But the real cost isn’t money - it’s effort.
You have to read labels. You have to say no to fried chicken. You have to plan meals. You have to deal with messy bathroom moments. If you’re not willing to do that, Alli won’t help you. But if you’re ready to take responsibility for what you eat, it can be a powerful tool.
Many people who start with Alli end up ditching it after six months - not because it didn’t work, but because they learned how to eat without it. That’s the real win.
Can I take Alli without dieting?
No. Alli only works if you reduce your fat intake. If you eat high-fat meals while taking it, you’ll experience unpleasant side effects and won’t lose weight. The pill doesn’t replace healthy eating - it supports it.
How long should I take Alli?
Most people use Alli for 6 to 12 months. The goal isn’t to stay on it forever - it’s to build better eating habits. If you haven’t lost at least 5% of your body weight after 12 weeks, it’s unlikely to work for you, and you should stop and talk to a doctor.
Does Alli burn belly fat specifically?
No. Alli doesn’t target fat in any one area. Weight loss happens all over the body. Belly fat tends to go last, no matter what product you use. Spot reduction is a myth.
Can I drink alcohol while taking Alli?
Yes, but be careful. Alcohol is high in calories and often mixed with sugary drinks. It doesn’t affect how Alli works, but it can sabotage your calorie deficit. Stick to dry wine or spirits with soda water if you drink.
Is Alli safe for long-term use?
Alli is considered safe for long-term use if taken as directed and paired with a balanced diet and multivitamin. Studies have shown no major safety concerns over two years. But if you’re using it beyond a year, check in with your doctor to monitor vitamin levels and liver function.
Next Steps
If you’re thinking about trying Alli, start by tracking your current diet for a week. Use an app to log your fat intake. If you’re eating more than 40 grams of fat per day, you’ll need to make big changes. Alli can help - but only if you’re ready to change your plate, not just your pills.
There’s no shortcut to lasting weight loss. Alli is one tool among many. The real power lies in what you do after you stop taking it.