Weight Loss and Appetite Suppressant Pills: What Works in the UK (October 2026)

01 · The core answer

Do appetite suppressant pills work for weight loss?

It depends entirely on which pill. Licensed prescription tablets produce meaningful average weight loss in trials, while shop-bought appetite suppressants have no comparable evidence and no clinical oversight.

The two prescription tablets work by acting on the GLP-1 receptor, the same hormone pathway used by weight-loss injections. They are used alongside a reduced-calorie diet and more physical activity. Individual results vary.²⁰²¹

No trial has compared Mounjaro directly with either tablet, so do not set their headline results side by side.¹⁵

02 · Your decision

What should you do next?

If you have a BMI of 30 or above, or 27 or above with a weight-related condition, you may be eligible for a licensed treatment. Start with a free consultation, reviewed by a GPhC-registered prescriber, who can discuss tablets and injections with you. Our weight loss clinic explains how this works.

If you prefer a once-weekly routine, the Mounjaro pen is the injectable option: your first 2.5mg pen costs £129.99 with code FIRST40 (standard price £169.99). For tablets, see the Wegovy pill and Foundayo pages for current prices.

03 · Wegovy tablets

Wegovy tablets: the appetite-reducing pill with a strict routine

Wegovy tablets contain semaglutide, the same active ingredient as the Wegovy injection, taken as one tablet once a day. They are licensed for weight management in adults with a BMI of 30 or above, or 27 to under 30 with at least one weight-related condition.²⁰

The routine is demanding. The tablet must be taken on an empty stomach after fasting for at least 8 hours, swallowed whole with a sip of water (up to half a glass, about 120ml), and you then wait at least 30 minutes before eating, drinking or taking other tablets. Treatment starts at a low dose and steps up gradually, with at least one month at each dose.²⁰

In the OASIS 4 trial, adults taking semaglutide 25mg tablets for 64 weeks lost on average 13.6% of their body weight, compared with 2.2% on placebo.²² Individual results vary. The most common side effects are digestive: nausea, vomiting, diarrhoea, constipation, indigestion and stomach pain, along with headache and tiredness.²²

04 · Foundayo

Foundayo: a GLP-1 tablet without food or water rules

Foundayo contains orforglipron, a once-daily GLP-1 tablet made by Eli Lilly, the maker of Mounjaro. Unlike Wegovy tablets it can be taken at any time of day, with or without food and without water restrictions. It has the same licensed BMI criteria as Wegovy tablets.²¹

In the ATTAIN-1 trial of 3,127 adults without type 2 diabetes, people taking the highest dose of orforglipron for 72 weeks lost on average 12.4% of their body weight, compared with 0.9% on placebo; the two lower doses gave 7.8% and 9.3%.²³ The trial used capsules, so tablet and capsule doses are not comparable milligram for milligram.

The most common side effects are digestive. Foundayo may make oral contraceptive pills less effective: switch to a non-oral method or add a barrier method for 30 days after starting and for 30 days after each dose increase.²¹

05 · Orlistat and supplements

Orlistat, supplements and "natural" suppressants

Orlistat is a licensed tablet, but it is not an appetite suppressant. It blocks some dietary fat absorption and produces smaller average losses than the GLP-1 medicines.

"Natural GLP-1" supplements, such as berberine, are not medicines. They are not regulated for this use and have no comparable trial evidence. They are available cheaply without assessment, and dosing is not standardised. That low barrier is a safety concern, not a benefit: nobody checks whether the product suits your health or other medicines.

This is also the honest answer to "how can I mimic Ozempic naturally?". No supplement reproduces a GLP-1 medicine. Our guides on natural appetite suppressant pills and whether weight loss pills work go into more detail.

06 · Tablet versus injection

Is there a tablet equivalent to Mounjaro?

No. There is no tablet form of Mounjaro, because tirzepatide is injection-only in the UK. Wegovy tablets and Foundayo are different medicines with their own dosing, eligibility checks and trial results.¹

Mounjaro is a once-weekly injection, while the tablets are taken daily. The practical differences matter as much as the averages: Wegovy tablets need a strict empty-stomach routine every morning, Foundayo has no food or water rules, and Mounjaro needs one injection a week. A prescriber will check which option is suitable for your health, your other medicines and your routine.²⁰²¹

SURMOUNT-5 is the trial that compared tirzepatide directly with injected semaglutide.¹⁵ If you want to understand the injectable route, read about a weight loss appetite suppressant injection or our prescription appetite suppressant shot guide.

07 · Safety and red flags

Safety: what to avoid when buying diet pills online

Be cautious of any seller offering to supply without a consultation or prescription, or promising specific results. Dramatic weight-loss claims are a warning sign, not a selling point.

Never combine prescription GLP-1 medicines with each other. Mounjaro must not be combined with other GLP-1 medicines, unlicensed "research" peptides, or compounded copies, because these combinations have no safety data and no regulated supply chain. If something promises faster results outside a licensed pathway, that is the warning sign.

Report suspected side effects or counterfeit medicines through the Yellow Card scheme.⁷ We are a GPhC-registered pharmacy (9012878), and every prescription order is reviewed by a GPhC-registered prescriber. Unsuitable orders are refunded automatically.

For wider comparisons, see our guides to appetite suppressant medication and how diet pills work.

08 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹

09 · NHS access

What about the NHS?

Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition, and the NHS primary-care rollout began in June 2025 with the highest-need groups first (initially BMI 40+ with four or more qualifying conditions).⁴⁶

Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting. Ask your GP what is available locally.