Grapefruit
Citrus paradisi · unripe whole fruitOne of the citrus sources of the ingredient’s characteristic flavanones.
A branded ingredient, clearly explained
What is Sinetrol® XPur C?
Sinetrol® XPur C is a standardised branded ingredient made from citrus fruits and guarana. Velisana Silhouette contains 630 mg per daily serving. Here, we explain openly what the ingredient consists of, how it is tested, which human studies have been published and where the limits of their conclusions lie.
First, an important note: The studies investigated the branded ingredient Sinetrol® XPur at defined study doses – not the finished product Velisana Silhouette. Study results are not a promise of efficacy and do not guarantee individual results.
4 sources Three citrus species plus guarana
at least 40% standardised flavanones according to the specification
4 human studies randomised and placebo-controlled
1 open-label study with two publications from the same cohort
The short answer
Not a single extract, but a defined blend
Sinetrol® is the brand name of a plant-based ingredient from Fytexia. “XPur C” refers to the concentrated variant used in Velisana Silhouette.
What “standardised” means
The manufacturer defines measurable markers and minimum or maximum values. This is intended to keep the composition controllable from batch to batch.
Pomelo
Citrus grandis · unripe whole fruitComplements the citrus profile and is listed separately in the manufacturer’s botanical documentation.
Orange / blood orange
Citrus sinensis · unripe whole fruitProvides additional citrus polyphenols, including the marker hesperidin.
Guarana
Paullinia cupana · seedsForms part of the blend and accounts for its naturally occurring caffeine content.
≥ 40% Flavanones, including hesperidin, naringin and neohesperidin
≤ 4% Caffeine as the specified maximum level of the ingredient
HPLC Batch testing by high-performance liquid chromatography
Important distinction: According to the Botanical Annex, the blend does not contain bitter orange (Citrus aurantium). According to the manufacturer, a daily amount of 630 mg XPur C provides approximately 22 mg of caffeine and no more than 26 mg. Due to several plant extracts, the complete Velisana daily serving contains approximately 48 mg of naturally occurring caffeine. The Annex lists furocoumarins only as a group of substances to be monitored; it does not state a limit.
XPur and XPur C
Why are 630 mg and 900 mg often compared?
Earlier clinical studies used 900 mg of Sinetrol® XPur daily. Velisana contains 630 mg of the concentrated XPur C variant. A 2018 manufacturer’s attestation compares the two daily amounts using selected constituent markers measured by HPLC.
| Measured marker | 900 mg XPur Batch 180221 |
630 mg XPur C Batch 180417-j5 |
|---|---|---|
| Caffeine | 19.35 mg | 20.92 mg |
| Isonaringin | 8.82 mg | 7.94 mg |
| Naringin | 193.41 mg | 196.81 mg |
| Hesperidin | 80.46 mg | 80.51 mg |
What the comparison shows
In the two tested batches, the measured amounts of the four markers per daily serving were similar. The manufacturer bases the “substantial equivalence” of the two ingredient amounts on these results.
What the comparison does not show
The attestation is not a new human study using 630 mg and is not clinical evidence of efficacy for the finished product Velisana Silhouette.
Source: Foodinnov Nutrition/Fytexia, manufacturer’s attestation dated 18 June 2018. Open original document
Published research
The human studies – chronological and without double-counting
The studies differ considerably in participant numbers, study design, duration and research question. We therefore assess each one individually instead of merely citing a large total.
4 randomised, placebo-controlled trials
1 open-label study with two scientific publications
2014 online in 2013
Twelve-week study involving 95 adults
For twelve weeks, 95 healthy adults with overweight received either 900 mg of Sinetrol® XPur daily or a placebo. Body measurements, body composition and tolerability were assessed.
n = 9547 active / 48 placebo
12 weeksobservation period
900 mg/daySinetrol® XPur
Interpretation: The controlled design is a strength. The corresponding author worked for the ingredient manufacturer Fytexia; this manufacturer involvement should be considered in the assessment.
2015 pilot study
Small pilot study involving 25 men
Twenty-five men with overweight were studied for twelve weeks. The trial compared 900 mg of Sinetrol® XPur per day with placebo and examined body measurements, body composition and selected metabolic markers.
n = 2512 active / 13 placebo
12 weeksobservation period
900 mg/daySinetrol® XPur
Interpretation: As a pilot study, it provides initial controlled data, but its small, exclusively male sample limits how widely the findings can be generalised.
2020 controlled trial
Twelve-week study involving 100 randomised adults
One hundred adults with overweight or obesity in South Korea were randomised; 86 completed the study. The trial compared 900 mg of Sinetrol® XPur per day with placebo. It focused on anthropometric measures, body composition and tolerability.
n = 10086 completed the study
12 weeksobservation period
900 mg/daySinetrol® XPur
Interpretation: Larger than the pilot study and placebo-controlled. The publication reports differences in some, but not all, of the assessed endpoints.
2023/24 the same study
Two publications from one open-label cohort of 20 people
Twenty adults were assigned a daily amount of either 900 or 1,800 mg for 16 weeks. The 2023 publication focused mainly on the absorption and metabolism of flavanones. The 2024 publication examined metabolic parameters, body composition and the gut microbiome, among other outcomes.
n = 20one participant cohort
16 weeksopen-label design
900 / 1,800 mgtwo doses
Interpretation: The two articles must not be counted as two independent human studies. Without a placebo group, changes cannot be clearly attributed to the ingredient. In the 2024 publication, the reported carbohydrate and fat intake also changed, which further complicates interpretation.
2026 online in 2025
Sixteen-week study involving 77 adults
Seventy-seven otherwise healthy men and women with overweight or obesity were studied for 16 weeks, followed by a four-week follow-up period. The trial compared 900 mg of Sinetrol® XPur per day with placebo alongside a normocaloric diet and habitual physical activity.
n = 77men and women
16 + 4 weeksstudy plus follow-up
900 mg/daySinetrol® XPur
Interpretation: The randomised, double-blind design strengthens the evidence compared with open-label studies. This trial also investigated 900 mg of XPur, not 630 mg of XPur C in the finished Velisana product.
Counting method: Published human studies are included. Two publications from the same participant cohort are counted as one study; language versions and identical duplicate files do not increase the study count.
Transparency on funding and conflicts of interest: Several papers in the research programme were funded by companies or include authors with links to the ingredient manufacturer. This does not automatically invalidate the results, but it should be considered alongside study design, sample size and reproducibility. The relevant disclosures are provided in the original publications.
Transparency on funding and conflicts of interest: Several papers in the research programme were funded by companies or include authors with links to the ingredient manufacturer. This does not automatically invalidate the results, but it should be considered alongside study design, sample size and reproducibility. The relevant disclosures are provided in the original publications.
Animal and cell models
Preclinical data provide background – not evidence in humans
The additional documents investigate possible biological mechanisms and selected safety aspects. They do not establish whether XPur C is effective or safe for long-term use in humans.
One experimental design, two analyses
- 24 male mice, including 18 leptin-deficient ob/ob mice
- 100 or 300 mg/kg body weight for seven weeks
- identical approval number KHUASP(SE)-15-019
Adipose-tissue biology without Sinetrol®
The accompanying reviews on white, brown and beige adipose tissue explain general principles. They do not investigate Sinetrol® and therefore do not support any product-specific claim.
No double-counting: The English and Korean documents are language versions. The 2016 and 2017 reports use the same animal experiment and are not presented as two independent efficacy studies.
Our interpretation
What can reasonably be concluded from the evidence – and what cannot
Good scientific communication distinguishes ingredient data, product data and personal expectations. These four points guide our assessment.
Defined ingredient
The botanical sources and key constituent markers are specified in manufacturer documentation.
Several human studies
Four trials were randomised and placebo-controlled; the open-label n=20 study provides less robust evidence.
Different study dose
The controlled trials tested 900 mg of XPur; Velisana contains 630 mg of the concentrated XPur C variant.
No finished-product evidence
The results do not automatically demonstrate a specific effect of the complete Velisana formula.
What is well documented
- which plants and plant parts XPur C contains,
- which markers are controlled according to the specification,
- that several human studies on the branded ingredient have been published,
- which study designs and doses were used.
What cannot be concluded
- a guaranteed or identical effect in every person,
- the treatment or prevention of disease,
- clinical equivalence between the finished product and the study preparation,
- a specific rate or extent of weight change.
Original documents
Not merely asserted – available to read directly
These technical manufacturer documents complement the scientific publications. They address different questions from a human study and are therefore presented separately.
Manufacturer document · PDF
Attestation of comparability
HPLC comparison of a 900 mg XPur batch with a 630 mg XPur C batch based on caffeine, isonaringin, naringin and hesperidin. Not a human study.
Open document ↗Specification · PDFBotanical Annex XPur C
Botanical identity, plant parts used, manufacturing overview, constituent markers and quality-control information; dated November 2024.
Open document ↗Preclinical · PDFAcute toxicology
OECD 423 animal study from 2014: a single dose of 2,000 mg/kg XPur in six female rats, plus six controls; no deaths or treatment-related abnormalities were reported. This is not evidence of long-term safety in humans and is not an XPur C human study.
Open document ↗Frequently asked questions
Answered briefly and clearly
Looking for a specific detail? Email us at office@velisana.shop.
Does Sinetrol® really work?
Several clinical human studies have shown measurable results. Sinetrol® has been studied in relation to body weight, body fat, BMI, as well as waist and hip circumference. This scientific basis was one of the main reasons why we chose Sinetrol® XPur C as the key ingredient in Velisana Silhouette.
Important: The published studies investigated Sinetrol® at the respective study dosages and not the complete Velisana Silhouette formula. Individual results may vary.
What do the clinical studies on Sinetrol® show?
Sinetrol® has been investigated in several published human studies conducted over a number of weeks. Researchers examined factors including body weight, body fat, BMI, as well as waist and hip circumference. The findings provide the scientific basis for why we selected Sinetrol® as the key branded ingredient in Velisana Silhouette.
On this page, you can find a transparent overview of the individual studies, their duration, the dosages investigated and their results.
Does Velisana Silhouette have side effects?
Sinetrol® showed a good tolerability profile in the published human studies. However, this does not mean that adverse effects can be ruled out for every individual.
Velisana Silhouette contains various plant extracts and approximately 48 mg of naturally occurring caffeine per recommended daily serving. People who are sensitive to caffeine should take this into account. As Sinetrol® XPur C also contains an ingredient derived from grapefruit, possible interactions with medications should be considered.
Who was Velisana Silhouette developed for?
Velisana Silhouette is designed for people who already pay attention to their diet and physical activity but are not seeing the progress they would like with their weight, figure or stubborn fat deposits.
The formula combines 630 mg Sinetrol® XPur C with selected plant extracts, as well as vitamin B6, zinc, chromium and magnesium, and can be easily incorporated into your daily routine with just three capsules a day.
What makes Sinetrol® XPur C special?
Sinetrol® is not an ordinary citrus extract, but a standardized branded ingredient based on selected citrus fruits with defined constituent markers. What makes it particularly interesting is the combination of standardization and scientific investigation in several clinical human studies.
Velisana uses the concentrated Sinetrol® XPur C variant at 630 mg per recommended daily serving.
Why does Velisana use 630 mg of Sinetrol® XPur C?
Velisana uses the concentrated XPur C variant. A manufacturer confirmation compares 630 mg of XPur C with 900 mg of XPur based on the characteristic constituent markers caffeine, isonaringin, naringin and hesperidin. In the batches analysed, comparable amounts of these markers were found per daily serving.
This allows Velisana Silhouette to use 630 mg of the concentrated XPur C variant as the heart of its formula. The comparison relates to the raw ingredients and does not constitute a separate clinical study of the finished Velisana product.
Why does Velisana combine Sinetrol® with additional plant extracts?
Because Velisana Silhouette was deliberately developed as a complete, distinctive formula. In addition to 630 mg Sinetrol® XPur C, the daily serving contains selected extracts of green tea, olive leaf, Coleus forskohlii and black pepper, as well as vitamin B6, zinc, chromium and magnesium.
The result is more than simply a Sinetrol® capsule: it is a comprehensive Velisana formula designed for your daily figure and weight-management routine.
How long should I take Velisana Silhouette?
One container contains 90 capsules and provides a 30-day supply when taking the recommended three capsules per day. If you want to integrate Velisana Silhouette consistently into your routine, three containers allow you to plan for a full 90 days.
The published human studies on Sinetrol® also investigated the ingredient over several weeks. Individual results may vary.
How much caffeine does Velisana Silhouette contain?
Velisana Silhouette provides approximately 48 mg of naturally occurring caffeine per recommended daily serving from Sinetrol® XPur C and the other plant extracts.
According to the ingredient documentation, approximately 22 mg and no more than 26 mg of this comes from 630 mg Sinetrol® XPur C. People who are sensitive to caffeine should take the total amount into account.
What should I consider if I take medication?
Sinetrol® XPur C contains, among other ingredients, a component derived from grapefruit. If you take medication for which grapefruit may be relevant, or if you have an existing medical condition, you should consult a doctor or pharmacist before use.
Please also follow the product label, recommended intake and warnings.
When your progress starts to stall
630 mg Sinetrol® XPur C – the heart of Velisana Silhouette
Velisana Silhouette combines the scientifically studied branded ingredient Sinetrol® XPur C with green tea, olive leaf, Coleus forskohlii and black pepper extracts, as well as selected vitamins and minerals – developed as a daily companion for your figure and weight management.
630 mg Sinetrol® XPur C per daily serving
With four additional selected plant extracts
Swiss Made, vegan, halal and laboratory tested
From
CHF 29.95
Choose my Velisana routine
Please refer to the product label, recommended intake and warnings. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle.