Electrolytes And Weight Loss Injections: UK Guide (October 2026)

01 · The short answer

Do you need electrolytes with weight loss injections?

The licensed regimen is one injection a week, used alongside a reduced-calorie diet and increased physical activity.¹ Our Mounjaro and electrolytes guide goes into more detail.

Whether electrolyte products suit you depends on your health, your other medicines and how you feel on treatment, so ask a prescriber who knows you.

02 · Getting started

How to get a weight loss injection properly

Mounjaro is a prescription-only medicine, supplied after an online consultation reviewed by a GPhC-registered prescriber.¹ Your first 2.5mg pen costs £129.99 with code FIRST40 (standard price £169.99). Every later order is £25 off the standard price, and all six doses are in stock.

• Free consultation: a short health questionnaire, with no charge and no obligation. Start your free consultation.
• Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.
• Dispatch and delivery: same-day dispatch when ordered by 3pm, with free next-day tracked delivery in temperature-controlled packaging.

Compare routes in our guides to buying weight loss injections in the UK and registering online.

03 · What treatment involves

What Mounjaro treatment actually involves

Mounjaro is tirzepatide, a once-weekly injection licensed in the UK for weight management in adults and for type 2 diabetes.¹ Everyone starts on 2.5mg, which is about letting your body adjust rather than weight loss itself. After at least 4 weeks the dose can step up gradually to a maximum of 15mg.¹

In SURMOUNT-1, adults lost on average 15% of body weight on 5mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone. These are trial averages and individual results vary.²

04 · Early side effects

Early side effects and when to ask for advice

Mild nausea, altered appetite and tiredness in the first days after each injection are the commonest early effects, and they usually settle.¹ Experiences differ widely between people.

If you notice anything new or that does not settle, speak to your prescriber rather than self-treating with supplements. If nausea or vomiting is persistent or you cannot keep fluids down, contact your clinical team — dehydration needs prompt attention. You can also report suspected side effects through the Yellow Card scheme.¹⁹ Our guide on whether weight loss injections are safe covers the wider picture.

05 · Spotting unsafe sellers

Beware add-on "electrolyte" or fat-burning injection offers

Be cautious of any seller offering to supply injections without a consultation or prescription, or promising specific results. Counterfeit medicine alerts are published by the MHRA.⁷ You can check any UK pharmacy on the GPhC register (ours is 9012878).¹²

Our guide to fraudulent weight loss injections explains what to look for. Our Mounjaro comes through official LillyDirect supply, direct from Eli Lilly's UK distribution.

06 · 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