Natural Appetite Suppressants in Australia
Evidence Rating
Evidence Rating
Moderate
Some clinical evidence, but mixed or modest results
Evidence varies by ingredient. Green tea extract has moderate evidence (~0.64 kg loss). Glucomannan shows promise but tablets are banned in Australia. 5-HTP has some evidence but is Schedule 4 at effective doses. Garcinia cambogia has weak evidence and safety concerns.
Natural Appetite Suppressants Key Facts
Some have modest evidence, most do not
Green tea extract has moderate evidence for small weight loss. Glucomannan and 5-HTP show some promise but face regulatory barriers in Australia. Garcinia cambogia has weak evidence and safety concerns.
Green tea extract (with caveats)
A 59-RCT meta-analysis found ~0.64 kg weight loss from green tea catechins. Modest but real. However, doses above 800 mg EGCG/day risk liver damage. Over 200 cases of liver failure have been documented globally.
Safety varies significantly by ingredient
Green tea extract: liver damage risk at high doses. Glucomannan tablets: banned in AU since 1985 (choking risk). 5-HTP: serotonin syndrome risk with SSRIs. Garcinia: TGA liver injury alert.
Important restrictions apply
Glucomannan tablets banned since 1985 (konjac noodles are legal). 5-HTP at 100 mg+/day is Schedule 4 (prescription-only). Green tea extract and garcinia are OTC but have safety alerts.
$10-40 per month
Green tea extract: $10-30/month. Garcinia cambogia: $15-40/month. Most are relatively affordable compared to prescription options.
Depends on the ingredient
5-HTP at 100 mg+/day requires a prescription (Schedule 4). Green tea extract and garcinia cambogia are OTC. Glucomannan tablets are banned entirely.
How Natural Appetite Suppressants Claims to Work
Various mechanisms depending on ingredient: green tea extract contains caffeine and EGCG which increase thermogenesis; glucomannan is a soluble fibre that expands in the stomach creating fullness; 5-HTP increases serotonin which reduces appetite; garcinia cambogia supposedly inhibits an enzyme involved in fat production.
What the Research Shows
Green tea catechins meta-analysis
59-RCT meta-analysis: ~0.64 kg additional weight loss with green tea catechins. Effect modest but statistically significant. Caffeine component likely contributes.
Cochrane Database / multiple reviews
59 RCTs
Glucomannan systematic review
Higher doses (5 g+/day) for 12+ weeks showed approximately 3 kg weight loss. However, results are mixed across studies, and konjac glucomannan tablets are banned in Australia.
Garcinia cambogia meta-analysis
Only 0.88 kg additional weight loss compared to placebo. Clinically insignificant. Associated with liver injury reports that prompted a TGA safety alert.
Source data from published peer-reviewed studies. Links open in a new tab to external medical databases.
Side Effects & Risks
Green tea extract risks
- Over 200 cases of liver failure documented globally
- Stay under 800 mg EGCG/day and take with food
- Higher risk in people with elevated BMI (EFSA 2018 finding)
Glucomannan risks
- Tablets banned in Australia since 1985
- Choking and oesophageal obstruction risk (including one case of perforation with mediastinitis)
- Konjac noodles (food form) are legal and safer
5-HTP risks
- Serotonin syndrome risk when combined with SSRIs/antidepressants
- 100 mg+/day is Schedule 4 (prescription-only) in Australia
- Most consumers are unaware of this regulatory threshold
Garcinia cambogia risks
- TGA safety alert issued for liver injury risk
- Over 200 liver injury reports globally
- Multiple case reports of acute hepatotoxicity
Australian Regulatory Status
Frequently Asked Questions
Other Supplements Reviewed
Berberine for weight loss
Evidence: Moderate | $35-75/mo
Apple Cider Vinegar for weight loss
Evidence: Weak | $3-25/mo
Protein Powder for weight loss
Evidence: Strong | $30-90/mo
Weight Loss Patches for weight loss
Evidence: None | $10-50/mo
Peptides for Weight Loss for weight loss
Evidence: Weak | $150-450/mo
Lemon Balm for weight loss
Evidence: None | $15-40/mo
Pink Salt (Himalayan Salt) for weight loss
Evidence: None | $1-5/mo
Medical disclaimer: This website is for informational purposes only. We are not medical professionals and nothing on this page constitutes medical advice, diagnosis, or treatment. Supplements are not a substitute for evidence-based medical treatment. Always consult a qualified doctor, pharmacist, or accredited practising dietitian before starting any supplement.
Supplements listed as AUST L on the Australian Register of Therapeutic Goods have been assessed by the TGA for safety and quality only, not for efficacy. An AUST L listing does not mean the TGA has verified that a supplement works for weight loss.
Data sourced from PubMed, Cochrane, TGA ARTG, FSANZ, and published clinical trial data. Last reviewed April 2026.