askmalcolm

Weight loss

Semaglutide and tirzepatide.

You've heard the brand names — Ozempic, Wegovy, Mounjaro, Zepbound. This page explains what the medication actually is, what the research found, what it does to your body, and what it can't do. It's long on purpose. This is a real decision.

What is it?

Semaglutide is a lab-made copy of a hormone your gut already releases when you eat. Your natural version breaks down within minutes. This one is engineered to last about a week, so one injection keeps working for seven days.

Tirzepatide is the same idea, except it copies two gut hormones instead of one. Think of it as the newer generation.

Semaglutide is a long-acting GLP-1 receptor agonist — a modified peptide mimicking glucagon-like peptide-1, an incretin hormone released post-prandially. Structural modification extends its half-life to roughly a week, permitting once-weekly subcutaneous dosing.

Tirzepatide is a dual GIP and GLP-1 receptor agonist: a single synthetic peptide activating two incretin receptors. Also once-weekly subcutaneous.

How does it work?

Three things at once.

It helps your pancreas handle sugar. It slows how fast your stomach empties, so you stay full longer. And — this is the one people actually notice — it turns down the hunger signal in your brain.

People describe that last part as the food noise going quiet. The constant background chatter about snacks stops. That's usually the first thing anyone reports, and it happens well before the scale moves.

Tirzepatide does all of that and adds a second hormone on top. Researchers don't fully agree on why the second one helps, but the weight-loss numbers in the trials were higher.

Three mechanisms. Glucose-dependent insulin secretion is stimulated and glucagon suppressed, lowering blood glucose. Gastric emptying is slowed. And GLP-1 receptors in hypothalamic and brainstem appetite centres are activated, reducing hunger signalling and food-reward valuation.

Tirzepatide adds GIP receptor agonism. GIP's contribution is still being characterised — proposed mechanisms include enhanced insulin sensitivity, effects on adipose nutrient handling, and central appetite effects that may blunt some GLP-1-driven nausea.

Why does it exist?

It was built to treat type 2 diabetes. The weight loss was an accident nobody planned for — it showed up in the diabetes trials and was dramatic enough that researchers ran an entirely new set of studies just for obesity.

Tirzepatide came from asking whether combining two gut hormones would beat one. The answer was yes.

What did the research actually find?

In the main obesity trial for semaglutide, average weight loss was around 15% of body weight over roughly 16 months. A separate large trial found it reduced heart attacks and strokes by about a fifth in people with excess weight and existing heart disease. That second finding matters — plenty of things move the scale, but very few have been shown to keep people out of hospital.

For tirzepatide, average weight loss at the top dose was around 21% over roughly 17 months — noticeably more. It also has a specific approval for obstructive sleep apnoea in people with obesity. What it doesn't yet have is semaglutide's proven track record on heart attacks and strokes; that data is still maturing.

Now the part you need to read twice

Those results come from trials of the branded, FDA-approved products — Wegovy and Zepbound. What I can help you get is a compounded medication containing the same active ingredient, prepared by a licensed pharmacy against your prescription.

Compounded preparations are not put through those trials and are not FDA-reviewed for safety, potency or quality before they ship. So I cannot honestly tell you that a compounded version will produce the trial results above, and neither can anyone else. Same active ingredient is a real thing. Same studied product is not.

I'd rather you have that clear going in. And if the branded product is within reach for you through insurance or a manufacturer program, that's a legitimately different and better-evidenced option — I'll tell you so rather than talk you out of it.

What actually happens, month by month?

That's the general shape from the clinical literature. Your experience may look different, and nobody can tell you in advance what yours will be.

Is this a good fit for you?

Points toward yes
  • You have real weight to lose, not ten vanity pounds
  • You've tried diet and exercise alone and hit a wall
  • You can afford it for a year or more, not just a month
  • You're willing to eat protein and do resistance training alongside it
Points toward wait
  • Medullary thyroid cancer or MEN2 runs in your family — that's a hard stop, not a caution
  • You've had pancreatitis
  • The cost would strain you into quitting in six months
  • You're expecting a short course and then done — that isn't how this works
  • You're pregnant, breastfeeding, or trying to conceive

These are things to raise on your intake form and with the provider. I'm not screening you — I'm telling you what the provider will be looking at so nothing catches you by surprise.

Real risks, stated plainly

Nausea, vomiting, diarrhoea and constipation are common, and worst in the week after each dose increase. Most people adjust. Beyond that:

  • Gallstones become more likely, because you're losing weight quickly.
  • Pancreatitis is rare but serious. Severe stomach pain that won't let up means call a doctor, not me.
  • There's a boxed warning for thyroid C-cell tumours, seen in rodent studies. Not for anyone with a personal or family history of medullary thyroid cancer or MEN2.
  • Some of what you lose is muscle. Lift weights and eat protein or you'll end up smaller and weaker rather than smaller and stronger.
  • Tell any surgeon or anaesthetist that you're taking it — delayed stomach emptying raises risk under anaesthesia.
  • The weight tends to come back when you stop. The studies are consistent on this. Plan for a long-term medication, not a course of treatment.

I'm not a clinician and this isn't a substitute for the conversation you'll have with one. It's what I'd want a friend to know before they decided.

Injection or under the tongue?

Injection

Once a week. A small needle into the fat just under the skin — belly, thigh or upper arm. Nothing like a blood draw. Most people are more anxious beforehand than after, and I'll walk you through the first one on the phone if you want.

Sublingual

Daily, under the tongue. No needle at all, and less expensive. If needles are the only thing standing between you and starting, this is why it exists.

What does it cost?

Brand-name products list well above $1,000 a month before insurance. What I can offer is considerably less than that, and the current numbers are on the pricing page — including what it renews at, not just the starting price.

Pricing in this category moves, so if anything looks out of date, call me for today's real number rather than trusting a figure printed on a page.

See current pricing

Questions people actually ask

Is this the same thing as Ozempic?

Same active ingredient. Ozempic and Wegovy are the FDA-approved brand products. A compounded version is prepared by a pharmacy against an individual prescription and is not FDA-reviewed for safety, potency or quality before it ships. Those are meaningfully different things and you should know which one you're buying. Ask me directly and I'll tell you.

Will I be on this forever?

Possibly, and you should plan as though yes. When people stop, most of the lost weight returns. Some taper to a lower maintenance dose. Nobody has a reliable way to take the full benefit and then walk away, and anyone telling you otherwise is selling.

How bad is the nausea really?

For most people: noticeable for a few days after each dose increase, then it settles. For a minority: bad enough to quit. Smaller portions, avoiding greasy food, and not rushing dose increases all help. If it's severe, the answer is usually to slow down rather than push through — and that's a conversation with the provider.

Which one should I take?

That's genuinely a provider decision, not something to settle off a website. Tirzepatide showed larger weight loss in trials. Semaglutide has the stronger evidence for reducing heart attacks and strokes. Your history and your goals go on the intake form and the provider makes the call.

Do I have to inject myself?

Not necessarily — there's a sublingual version. If you do go with injections, it's once a week with a small needle. I'll talk you through the first one.

What if I'm turned down?

Full refund. You're not stuck paying for something you weren't approved for.

The part the medication doesn't do

It makes eating less easier. That's the whole job. Protein, water, sleep and moving your body still matter — and they matter more once your appetite drops, because that's exactly when people accidentally undereat and lose muscle along with the fat.

If you want help with that side of it, ask me. It's the part I actually know something about, and it's free.

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