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Evidence rating: Preliminary — the metabolic ingredients have human trials, but the meta-analyses mostly point to effects too small to matter
What All Day Slimming Tea Claims To Be
All Day Slimming Tea is a two-part herbal tea program: a Morning Energy Tea intended to lift metabolism and energy, and an Evening Detox Tea intended to support digestion overnight. The promise is weight loss, a flatter stomach, and better energy, achieved by drinking tea rather than by changing anything else.
Splitting a product into a stimulating morning blend and a relaxing evening blend is a sensible bit of formulation. But the two halves work through very different mechanisms, and one of them deserves a much closer look than the marketing gives it.
What’s Actually In It
Morning Energy Tea: green tea, oolong tea, orange peel, lemongrass, ginger, dandelion leaf, ginseng root, Garcinia cambogia, with monk fruit and honey lemon flavouring.
Evening Detox Tea: senna leaves, licorice root, peppermint leaves, ginger.
No quantities are given for any component of either blend. That is common for tea products, but it means there is no way to compare the caffeine or catechin content to the doses used in the research below.
What The Research Shows
Based on articles retrieved from PubMed, the metabolic story here is real but very small, and the evening blend raises a genuine safety point.
Green tea’s effect on weight is either tiny or absent, depending on which meta-analysis you read. One meta-analysis of 11 studies found catechins or an EGCG-caffeine mixture produced a statistically significant but small reduction in body weight — about 1.3 kg — and helped with weight maintenance after a loss. Habitual caffeine intake above 300 mg a day appeared to blunt the effect. DOI
A stricter analysis found nothing worth having. Restricting inclusion to randomized, double-blind, placebo-controlled trials of at least 12 weeks in overweight and obese adults, a second meta-analysis found no statistically significant effect of green tea on body weight (-0.78 kg, not significant), BMI, waist circumference, or hip circumference. It found a small significant reduction in body fat percentage — 0.76% — which the authors themselves described as “not clinically relevant.” Their conclusion was unambiguous: green tea exerts no significant effect on the weight of overweight or obese adults. DOI
Oolong tea does shift fat oxidation, without shifting energy expenditure. In a randomized, placebo-controlled, double-blind crossover trial, twelve non-obese men took oolong tea, caffeine, or placebo twice daily for 14 days, measured with whole-room indirect calorimetry. Both oolong and caffeine increased fat oxidation by around 20% over 24 hours — but neither increased total energy expenditure. Burning a different fuel is not the same as burning more calories, and it is calorie balance that determines weight. DOI
Garcinia cambogia did not survive review. A systematic review and meta-analysis of 54 randomized placebo-controlled trials of herbal weight-loss medicines set a threshold of 2.5 kg as clinically significant. Garcinia cambogia showed no effect at all. Camellia sinensis — green tea — likewise showed no effect as a single agent. The reviewers’ overall conclusion: “There is currently insufficient evidence to recommend any of the herbal medicines for weight loss included in the present review.” DOI
The evening blend is where we would urge real caution. Senna is an anthranoid laxative. A review of this drug class explains that the active compounds work by damaging colonic epithelial cells, which is what produces the laxative effect. Chronic use is associated with pseudomelanosis coli, and both laboratory and animal work has suggested a role for anthranoid laxatives in tumour initiation and promotion, with human studies pointing the same direction. The review’s bottom line: short-term use is generally safe, but long-term use cannot be recommended. DOI
Any weight change you see in the first days of a senna-containing product is water and stool weight, not fat loss.
The Honest Verdict
What holds up: Green tea and oolong tea are healthy, pleasant, well-tolerated drinks with genuine antioxidant content, and there is a measurable metabolic signal in the oolong data. Replacing sweetened drinks with unsweetened tea is a real, if unglamorous, improvement. Ginger and peppermint have reasonable traditional standing for digestive comfort. If you enjoy tea, drinking more of it is not a bad habit.
What doesn’t: Almost the entire weight-loss claim. The strictest green tea meta-analysis found no effect on body weight. The 54-trial herbal review found neither green tea nor Garcinia cambogia produced clinically significant weight loss. The oolong trial found increased fat oxidation with no increase in energy expenditure. Taken together, the honest reading of this evidence is that these ingredients will not meaningfully change your weight.
Who this makes sense for: Someone who wants a flavoured tea habit as one small part of an actual diet-and-activity change, who is drawn to the morning blend, and who would be equally happy skipping the evening one.
Who should skip it: Anyone planning to use the evening senna tea daily or for more than a short period — the anthranoid laxative safety literature is a genuine concern, not a technicality. Anyone with IBS, inflammatory bowel disease, or a history of disordered eating. Anyone on medication, since senna affects absorption and licorice root can raise blood pressure and deplete potassium. And anyone expecting this to substitute for a calorie deficit — the evidence simply does not support that.
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This article is for informational purposes only and is not medical advice. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the Food and Drug Administration. Talk to your physician before starting any supplement, especially if you have a diagnosed condition or take medication.
Research cited via PubMed: