What is inside
Lemon Bottle is a brand of liquid made by SID Medicos. The company is in Seoul, South Korea. It is sold online and on social media as a “fat dissolving” liquid. Sellers also call it a “lipolysis” (fat breakdown) solution. Regulators in Switzerland, the United States and the UK all say it is being injected. But the company that sells it told regulators it is a cosmetic, meant only for use on the skin.
The maker lists three main ingredients:
- riboflavin (vitamin B2)
- bromelain (enzymes from pineapple)
- lecithin (a fatty substance from soybeans or egg yolk)
It also lists unnamed “natural ingredients”. The full recipe and the amounts are not published.
Nobody can be sure what is in a given pack. In 2024, the Swiss regulator tested samples from different sellers. It could not find the listed ingredients. One sample held only caffeine.
Declared composition, from packaging and marketing as summarised by Swissmedic: mainly bromelain, lecithin and riboflavin, plus several unspecified natural ingredients. No quantitative formula has been published, and the product has no PubChem, CAS or pharmacopoeial identity. Marketing quoted in FDA’s 2025 warning letters attributes the effect to lecithin breaking down fat-cell membranes and to riboflavin helping the body discharge dissolved fat faster than normal metabolism; those are the seller’s claims, not findings.
Analytical data: the official Swissmedic laboratory analysed samples of “Lemon Bottle” lipolysis solution obtained from various sources and reported in March 2024 that the ingredients did not match the declaration and varied greatly from pack to pack. In one sample the only substance found was caffeine; in another none of the listed ingredients could be detected. Swissmedic described these samples as falsifications. No independent peer-reviewed analysis, sterility or endotoxin testing, or stability data for authentic product were found, and nothing is known about the pharmacokinetics of any component after subcutaneous injection of this product.
Ingredient: Riboflavin
Riboflavin is vitamin B2. We get it from milk, eggs, meat and cereals with added vitamins. The body turns it into two helper molecules. Many enzymes need these helpers to get energy from food. This includes the enzymes that burn fat for fuel inside cells. Riboflavin is bright yellow, and light breaks it down.
The marketing claims lean on this normal role in the body. But that does not mean injecting it into a patch of fat breaks the fat down. It also does not mean the fat clears faster. No study was found that shows either effect. The FDA has approved riboflavin (in a form called riboflavin phosphate) in some products. These are multivitamins given into a vein, and eye drops used in an eye procedure. Neither one has anything to do with losing fat.
Riboflavin (7,8-dimethyl-10-D-ribityl-isoalloxazine, C17H20N4O6, 376.4 g/mol, PubChem CID 493570) is converted by riboflavin kinase and FAD synthetase to flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These are prosthetic groups of flavoproteins including respiratory-chain complexes I and II and the acyl-CoA dehydrogenases that catalyse the first step of mitochondrial fatty-acid β-oxidation. That is the intracellular oxidation of fatty acids already released from triglyceride; riboflavin is not a lipase, a detergent or an adipocytolytic agent. No evidence was found that extra riboflavin in a person who is not deficient increases fat oxidation, and PubMed contains no study of locally injected riboflavin reducing subcutaneous fat.
Riboflavin is water-soluble and photolabile. Its 5’-phosphate ester is the photosensitiser in Photrexa and Photrexa Viscous, FDA-approved in 2016 for corneal collagen cross-linking with ultraviolet light in progressive keratoconus, and is the riboflavin source in intravenous multivitamin products such as Infuvite Adult.
Ingredient: Bromelain
Bromelain is a mix of enzymes from the pineapple plant. These enzymes break down protein. It comes from the stem and the fruit. It is sold as a supplement. It is also used to make meat more tender. The FDA has approved one medicine made from pineapple-stem enzymes. It is called NexoBrid. It is a gel spread on bad burns for a few hours. It breaks down dead, burned tissue. It is not injected.
A 2012 lab study used mouse fat cells in dishes. Bromelain stopped young fat cells from growing up. It also made grown fat cells die and release their fat. This was only in lab dishes. No study was found that shows injecting bromelain into human fat reduces it. Nobody has studied what happens when this kind of enzyme is injected under human skin.
Bromelain is a crude extract of Ananas comosus containing several cysteine proteases, principally stem bromelain (EC 3.4.22.32) and fruit bromelain (EC 3.4.22.33), with smaller amounts of ananain and comosain; it is a protein mixture, not a single molecule. The enzymatic debriding agent anacaulase-bcdb (NexoBrid), a mixture of pineapple-stem enzymes, was approved by the FDA on 2022-12-28 as a topical gel applied for four hours to remove eschar in adults with deep partial-thickness or full-thickness thermal burns, based on two trials in 357 patients.
Adipocyte data: Dave et al. (PLoS One 2012) reported that stem bromelain irreversibly inhibited differentiation of 3T3-L1 preadipocytes by down-regulating C/EBPα and PPARγ, and in mature 3T3-L1 adipocytes induced apoptosis and lipolysis through Akt inhibition and augmented TNF-α signalling, with reduced perilipin and PDE3B expression. These are in-vitro findings in a mouse cell line at culture concentrations. No animal or human study of injected bromelain for localised fat reduction was found.
Ingredient: Lecithin
Lecithin is a name for a group of fatty substances. They are the main building blocks of the outer layer of cells. Most lecithin comes from soybeans, sunflower seeds and egg yolk. It is often added to food to keep oil and water mixed. Its main part is called phosphatidylcholine.
Phosphatidylcholine has long been used in “fat dissolving” shots. It is usually mixed with a bile salt called deoxycholate. The FDA says both are common in fat-dissolving shots that it has not approved. A 2004 lab study looked at these mixes. It found the fat-killing effect came mainly from the deoxycholate, not the phosphatidylcholine. Deoxycholate works a bit like soap. No study was found that shows lecithin shrinks fat when injected without a soap-like substance.
Lecithin is a mixture of glycerophospholipids, chiefly phosphatidylcholine (PC) with phosphatidylethanolamine, phosphatidylinositol and phosphatidic acid, whose proportions depend on source and fractionation; it has no single formula. PC is amphiphilic and does not dissolve in water as single molecules, so aqueous injectables require a solubiliser or form liposomes.
Rotunda et al. (Dermatol Surg 2004) compared a clinical PC injection, isolated sodium deoxycholate and the laboratory detergents Triton X-100 and Empigen BB in cell culture and porcine tissue. The PC formula and deoxycholate alone produced comparable loss of cell viability, membrane lysis and disruption of fat and muscle architecture, similar to the laboratory detergents. The authors concluded that the formula works primarily as a detergent causing nonspecific cell lysis and that deoxycholate is the major active component. Deoxycholic acid was later approved on its own as Kybella. The three declared main ingredients of Lemon Bottle do not include deoxycholate or another recognised detergent, so the mechanism established for PC–deoxycholate products does not carry over; the lecithin content and how it is solubilised are unpublished.
Why researchers might study these together
The maker explains the product as a chain of steps. Its ads, quoted in FDA warning letters, make two claims. They say lecithin breaks open fat cells. They say riboflavin helps the body get rid of the melted fat faster than normal. Bromelain, an enzyme that breaks down protein, is the third ingredient. Each step borrows a real fact about an ingredient. But nobody has tested whether these facts add up to melting fat under the skin.
No trial of Lemon Bottle is listed on ClinicalTrials.gov. No published study of the product was found in PubMed. The lab evidence on its ingredients comes down to two things. There is one study of bromelain in lab dishes. There is older work on phosphatidylcholine mixes. In that work, the fat-killing effect came from a soap-like salt that Lemon Bottle does not list. The mix of ingredients has never been tested in animals or people.
Framed as a hypothesis, the proposed mechanism has three parts: disruption of adipocyte membranes by phospholipid (lecithin), pro-apoptotic and lipolytic effects on adipocytes (bromelain, by analogy with the 3T3-L1 data of Dave et al., 2012), and faster oxidation of released fatty acids (riboflavin, by analogy with FAD’s role as cofactor of the acyl-CoA dehydrogenases). None of the three analogies has been tested in vivo for this purpose, and there is no published rationale for their combination or proportions.
The membrane-disruption step is the weakest link: in the PC–deoxycholate literature, cytolytic activity was attributed to the detergent rather than to PC (Rotunda et al., 2004), and no detergent is declared. The riboflavin step assumes that cofactor supply limits fat oxidation, for which no evidence in non-deficient tissue was found. The bromelain step extrapolates from a mouse cell line to human subcutaneous tissue. Finally, Swissmedic’s laboratory findings mean that even a well-designed study would first need to establish what the product actually contains. No trial is registered and no animal study of the product was found.
Regulatory picture
Approval: no medicine regulator has approved Lemon Bottle. In 2024, the company that sells it told the Swiss regulator the real product is a cosmetic. It said it is only for use on the skin. No approval in South Korea as a drug or medical device was found. No statement about it from South Korea’s drug safety agency was found either.
Regulators that have acted:
- Switzerland (2024) said the injected product is a medicine that has not been approved. It may not be sold or used. The regulator also found fake samples.
- The US FDA (2025) sent warning letters to five online sellers. It called Lemon Bottle an unapproved new drug. That is because the law treats a product sold to dissolve fat as a drug.
- The UK pharmacy regulator (2025) warned pharmacists about supplying or injecting it.
No statement just about Lemon Bottle was found from the UK drug regulator (MHRA) or Australia’s drug regulator (TGA).
United States: FDA held that claims such as “LEMONBOTTLE LIPOLYSIS” and “non-surgical alternative to liposuction” establish intended use to affect the structure or function of the body, making the product a drug under section 201(g)(1) and, with no approved application, an unapproved new drug under sections 505(a) and 301(d). By contrast, deoxycholic acid injection (Kybella, NDA 206333, approved 2015-04-29) is labelled only for moderate to severe submental fullness in adults. Its approval rested on two randomised, double-blind, placebo-controlled trials (1,022 subjects) with at least 2-grade composite responses of 13.4% versus under 0.1% and 18.6% versus 3.0% on placebo, and its label warns of marginal mandibular nerve injury, dysphagia and injection-site ulceration and necrosis. FDA’s consumer page calls Kybella the only FDA-approved fat-dissolving injectable.
Switzerland: the cross-agency Expert Panel for Delimitation Questions classified the injected product as a medicinal product; a June 2024 addendum maintained this despite cosmetic labelling.
Compounding: the 503A framework concerns bulk ingredients, not finished imported products, so status is recorded as unknown.
