No prescription needed·25 products reviewed

Supplements

Over-the-counter options from FDA-approved Alli to popular supplements like berberine and protein powder. Evidence levels vary dramatically — from robust to essentially none.

Most supplements produce small effects compared to prescription medications. The best-supported options may contribute 1–3 kg of additional weight loss — meaningful for some people, but a fraction of what approved drugs achieve.

Quick read · 3 min

How we rate evidence

StrongFDA-approved or backed by large, well-conducted trials where people were randomly assigned to get the supplement or a dummy pill.
ModerateMultiple trials showing consistent but modest effects. Worth discussing with a doctor.
WeakLimited or inconsistent trial data. Effects are small or not reliable across studies.
Very weakLittle to no reliable trial data supporting use for weight loss.

Important context

Supplements are regulated differently from prescription drugs. The FDA does not review supplements for effectiveness before they are sold. This means a product can be marketed for weight loss without proving it works. The evidence levels on this page are based on published clinical trial data — not marketing claims.

StrongStrong evidence
Strong

Orlistat OTC (Alli)

~2.9 kg more than placebo· ~$40–$60/mo
ModerateModerate evidence
Moderate

Berberine

~2.1 kg more than placebo· ~$20–$50/mo
Moderate

Protein Supplements

Supports fat loss & fullness· ~$30–$80/mo
Moderate

Caffeine

~0.4–0.5 kg (short-term)· ~$5–$20/mo
Moderate

Psyllium Husk

~2.1 kg (in overweight adults)· ~$10–$25/mo
Moderate

Chitosan

~1.7 kg more than placebo· ~$15–$30/mo
Moderate

Nigella Sativa (Black Seed Oil)

~2.1 kg more than placebo· ~$15–$40/mo
Moderate

Spirulina

~1.8 kg more than placebo· ~$15–$30/mo
Moderate

Curcumin (Turmeric)

~0.8 kg more than placebo· ~$15–$30/mo
Moderate

Fibre Supplements (General)

Modest, varies by type· ~$10–$25/mo
Moderate

Saffron Extract (Crocus sativus)

Reduces appetite (modest data)· ~$20–$40/mo
WeakWeak evidence
Limited evidence supports these for weight loss. “Natural” does not mean risk-free — always check with a doctor before taking supplements.
Weak

Glucomannan (Konjac Fibre)

Not statistically significant· ~$15–$30/mo
Weak

Green Tea Extract (EGCG / Catechins)

~0.95 kg in meta-analysis· ~$15–$40/mo
Weak

Conjugated Linoleic Acid (CLA)

~1.3 kg over 6 months· ~$20–$40/mo
Weak

Chromium Picolinate

~1.1 kg in meta-analysis· ~$5–$15/mo
Weak

Green Coffee Bean Extract

Limited reliable data· ~$15–$30/mo
Weak

L-Carnitine

~1.3 kg in meta-analysis· ~$10–$25/mo
Weak

Capsaicin (Cayenne Pepper)

Minimal (~50 kcal/day extra burn)· ~$10–$20/mo
Weak

5-HTP (5-Hydroxytryptophan)

~5 kg (small, older trials)· ~$10–$25/mo
Weak

Ashwagandha (Withania somnifera)

~3% body weight (stress-related)· ~$15–$35/mo
Very weakVery weak evidence
Limited evidence supports these for weight loss. “Natural” does not mean risk-free — always check with a doctor before taking supplements.
Very weak

Garcinia Cambogia

~1.3 kg (inconsistent results)· ~$10–$25/mo
Very weak

Raspberry Ketones

No human trial evidence· ~$10–$25/mo
Very weak

Apple Cider Vinegar (ACV)

Key study retracted in 2025· ~$5–$15/mo
In simple terms:
  • •Evidence varies enormously — from FDA-approved (Orlistat OTC) to virtually no reliable trial data
  • •Even the best-supported supplements produce modest weight loss — typically 1–3 kg in trials
  • •"Natural" does not mean risk-free — some supplements interact with medications
  • •None replace prescription treatment for people who qualify — but some can complement a broader approach

Based on clinical trials · No rankings · Every claim linked to source

Last reviewed: April 2026

When to reconsider: If you have tried lifestyle changes and supplements without achieving the results you are looking for, prescription medications may be worth discussing with your doctor. See all prescription options →

Medical disclaimer: This website is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any treatment.

Next step most people take

See prescription medications
FDA-approved drugs with substantially larger trial results
Compare all options
Supplements, medications, diet and exercise side by side