Non-GLP-1 Weight Loss Shots: Do B12, Lipotropic (MIC) & HCG Work?

Before Ozempic and Zepbound, the injectables sold at diet clinics and med-spas were B12 shots, lipotropic (“MIC”) injections, and HCG shots. People still search for these because they are cheap, needle-based, and marketed for weight loss — so they get mentally filed next to the GLP-1 “weight loss shots.” They do not belong in the same category. B12 does not cause weight loss unless you are genuinely B12-deficient; lipotropic/MIC shots have no controlled trial showing fat loss; and the FDA states there is “no substantial evidence” that HCG increases weight loss and prohibits weight-loss claims for it^[1]. This article explains what each one actually is, who (if anyone) benefits, and why the shots with real trial evidence are the GLP-1s.

The honest summary

• B12 shots do not cause weight loss unless you are deficient. A meta-analysis of 16 randomized trials in 6,276 non-deficient adults found B12 supplementation ineffective for fatigue, mood, and cognition^[2] — the same “boosts energy, burns fat” logic the shots are sold on. Correcting a real deficiency matters for nerve and blood health, but it does not move the scale.
• Lipotropic / MIC shots have no controlled evidence of fat loss. The “MIC” blend is methionine, inositol, and choline — choline is a genuine essential nutrient involved in liver fat metabolism^[3], but no randomized trial shows that injecting this mixture produces weight or fat loss in humans.
• HCG is not approved for weight loss and the claims are prohibited. The FDA states the prescription HCG label carries “no substantial evidence” of increased weight loss, and over-the-counter HCG weight-loss products are illegal^[1]. A criteria-based meta-analysis found HCG no better than placebo for weight, fat distribution, hunger, or well-being^[4].
• The weight loss comes from the starvation diet, not the shot. HCG protocols pair the injection with a 500-calorie-per-day diet. Anyone eating 500 calories a day loses weight — the hormone adds nothing^[1][4].
• The shots with real evidence are the GLP-1s. Semaglutide (Wegovy) produced ~15% body-weight loss in STEP-1^[8] and tirzepatide (Zepbound) ~21% in SURMOUNT-1^[9] — an entirely different order of magnitude, from randomized trials.

B12 shots: real for deficiency, useless as a weight-loss tool

Vitamin B12 (injectable cyanocobalamin or hydroxocobalamin, typically 1,000 mcg intramuscularly) is FDA-approved for treating documented B12 deficiency, pernicious anemia, and malabsorption syndromes — not for weight loss. The marketing story is that B12 “boosts metabolism and energy,” because B12 participates in converting food into cellular energy. That is true only when B12 is missing. In a person with normal B12 status, extra B12 cannot push energy production above the body’s homeostatic set point, because B12 availability is not the rate-limiting step. The Markun 2021 systematic review and meta-analysis^[2] pooled 16 randomized trials in 6,276 non-deficient adults and found no effect of B12 supplementation on cognitive function or depressive symptoms, with a fatigue evidence base too thin to even meta-analyze. That is the most relevant negative datapoint for the “B12 boosts energy” claim the shots are built on.

There is a real epidemiologic association — serum B12 tends to run lower in people with obesity (Sun 2019 NHANES, n=9,075; highest B12 quartile had an adjusted odds ratio of 0.71 for obesity versus the lowest)^[5] — but the direction is wrong for it to work as a treatment. That finding says obesity is associated with lower B12, not that low B12 causes obesity or that a B12 shot causes weight loss. Where B12 genuinely matters in the weight-loss era is deficiency correction: long-term metformin depletes B12 (Aroda 2016 DPPOS: odds ratio 1.13 per year of metformin use)^[6], and vegans and strict vegetarians need routine supplementation^[7]. Those are health reasons to test and treat — not reasons to expect the scale to move. For the full breakdown, see our B12 and weight loss evidence review.

Lipotropic / MIC injections: an essential nutrient, no fat-loss trials

“Lipotropic” injections — often sold as the MIC shot — are a compounded blend of methionine, inositol, and choline, frequently with added B vitamins. “Lipotropic” literally means “promoting the movement of fat,” and the pitch leans on choline’s legitimate biology: choline is an essential nutrient and a methyl donor the body uses to make phosphatidylcholine, a phospholipid involved in packaging and transporting fat out of the liver^[3]. From that real biochemical role, clinics extrapolate a weight-loss claim. The extrapolation is not supported: there is no randomized controlled trial showing that MIC or lipotropic injections cause weight loss or fat loss in humans. Having a role in a metabolic pathway is not the same as being a fat-burning therapy, especially in people who already get adequate choline from food.

In practice, MIC shots are almost always sold as an add-on inside a package that also includes calorie restriction, sometimes phentermine, and a clinic visit — so any weight change is attributable to the diet and the stimulant, not the MIC blend. If a provider frames a lipotropic injection as the reason you will lose weight, treat that as a marketing claim without trial support. Choline deficiency is real but uncommon in people eating a mixed diet; if it is a concern, it is a nutrition conversation, not a weight-loss shot.

HCG shots: the FDA says no, and the weight loss is the diet

HCG (human chorionic gonadotropin) is a hormone produced by the placenta during pregnancy. The “HCG diet,” popularized by the Simeons protocol decades ago, pairs HCG (as injections, drops, or sprays) with an extreme 500-calorie-per-day diet and claims the hormone specifically melts fat and blunts hunger. The FDA is unusually direct about this. Its consumer guidance states HCG “is not approved for weight loss,” and quotes the prescription drug label verbatim: there “is no substantial evidence that it increases weight loss beyond that resulting from caloric restriction, that it causes a more attractive or ‘normal’ distribution of fat, or that it decreases the hunger and discomfort associated with calorie-restricted diets.”^[1] Over-the-counter HCG products marketed for weight loss — including “homeopathic” drops — are illegal^[1].

The clinical literature agrees. The Lijesen 1995 criteria-based meta-analysis^[4] evaluated the Simeons HCG-for-obesity trials and concluded there is no scientific evidence that HCG causes weight loss, redistributes fat, reduces hunger, or induces a feeling of well-being beyond what the diet alone achieves. The uncomfortable core of the HCG diet is that a 500-calorie-per-day intake will produce rapid weight loss in almost anyone — that severe a deficit is also potentially unsafe without medical supervision — and the injection contributes nothing to the result. You are paying for a hormone to take credit for a starvation diet.

What actually works: the GLP-1 shots

When a “weight loss shot” has real randomized-trial evidence, it is a GLP-1 (or GLP-1/GIP) medication. Semaglutide (Wegovy) produced a mean ~14.9% reduction in body weight over 68 weeks in the STEP-1 trial^[8], and tirzepatide (Zepbound) produced ~20.9% over 72 weeks in SURMOUNT-1^[9]. These are placebo-controlled Phase 3 results, not clinic testimonials, and they are one to two orders of magnitude beyond anything B12, MIC, or HCG has ever shown. If you want the shot that moves the scale, that is the category — see our semaglutide and tirzepatide guides, or the ranked weight loss injections. And note that these GLP-1 drugs are themselves peptides — the peptide question has its own honest review in peptide shots for weight loss.

Bottom line

B12, lipotropic/MIC, and HCG shots are the older injectables people confuse with the GLP-1 “weight loss shots.” None of them causes weight loss on its own: B12 helps only if you are deficient^[2], MIC has no controlled fat-loss evidence^[3], and the FDA states HCG has no substantial evidence and bans the weight-loss claims^[1][4]. If a clinic sells any of these as a weight-loss shot, treat it as a red flag. The shots that work are the GLP-1s.