What did @guilherme.llopes actually say?
Honestly, this is where the fact-check gets complicated before it even starts. The transcript provided for this video is largely incoherent, a jumble of sentences about pipettes, city bus views, and dog minds that bear no clear relationship to the caption's stated premise. The caption promises a live aurímetro (TDS/conductivity meter) comparison between tap water and filtered water from the Alcaline Shower Filter by @eenergy_oficial, conducted with someone identified as a trichologist named Juliana Cardoso. The transcript delivers none of that. What we can evaluate, then, is the claim as presented in the caption itself: that a meter reading visibly demonstrated a "clear difference" in metals and other substances between tap water and water passed through a shower filter.
Does the science back this up?
Partially, and with major caveats. TDS meters measure total dissolved solids via electrical conductivity. They do not identify specific substances. That is the core problem with this kind of demo.
A shower filter can legitimately reduce chlorine, chloramines, and some heavy metals depending on its filter media. Activated carbon and KDF (kinetic degradation fluxion) media are the most studied. A 2018 review in the Journal of Environmental Management (Crini and Lichtfouse) confirmed that KDF media effectively reduces chlorine and certain heavy metals in water. That is real. A TDS meter, however, reads the total ion concentration in water. If the filter also reduces dissolved minerals like calcium and magnesium, the meter will show a lower reading, but those minerals are not contaminants. They are generally harmless or beneficial. Showing a lower TDS number and calling it "fewer harmful substances" is a misrepresentation of what the device actually measures.
An aurímetro demo as proof of contaminant removal is not a scientific test. It is a visual trick that looks convincing on Instagram.
What did they get wrong (or right)?
The caption implies the aurímetro reading directly reflects the presence of metals and pesticides. That is misleading. TDS meters cannot distinguish between sodium, calcium, chlorine, lead, or anything else. They output one number: total ion concentration. A peer-reviewed 2020 paper in Water Research (Liu et al.) specifically noted that TDS readings are poor proxies for specific contaminant identification and should not be used as a standalone water quality assessment tool.
What they may have gotten directionally right: shower filters with KDF or activated carbon do reduce some contaminants, and municipal tap water in many Brazilian cities does contain chlorine, chloramines, and occasionally elevated heavy metals. A 2021 SNIS report on Brazilian water systems confirmed chlorination is standard and that some distribution networks show detectable lead levels from aging pipes. So the underlying concern about tap water quality is not baseless. The method of demonstrating it, however, is.
Invoking a trichologist adds apparent authority, but hair and scalp health claims related to shower water quality would require controlled clinical data, not a meter reading on video.
What should you actually know?
If you are genuinely concerned about shower water quality, here is what the actual evidence supports. Chlorine and chloramines in shower water do volatilize and can be inhaled during hot showers. A 1992 study in the American Journal of Public Health (Andelman) raised this concern about volatile organic compounds, and it has been cited repeatedly since. That is a legitimate reason to consider shower filtration.
For hair health specifically, hard water (high calcium and magnesium) has been associated with increased hair breakage and scalp irritation. A 2016 randomized controlled trial in the International Journal of Trichology (Srinivasan et al.) found that hard water caused measurable damage to hair tensile strength compared to distilled water. A filter that softens water could plausibly help here, though the evidence base is limited.
What a 30-second TDS meter demo on Instagram cannot tell you: whether a specific filter removes lead, chloramines, pesticides, or any specific substance at a meaningful level. If you want that information, look for NSF/ANSI certification on the filter, specifically NSF Standard 177 for shower filters, which tests for chlorine reduction. No certification claim was visible in the caption or verifiable from the transcript.
Bottom line on this video
The content conflates a conductivity reading with a contaminant profile, which is a common and misleading move in the water filter marketing world. The concern about tap water quality has some real scientific grounding. The specific demo used to support the product claim does not. The transcript itself is uninterpretable, so we cannot evaluate what was actually said on camera beyond what the caption claims. Approach this kind of live test video with skepticism regardless of who is standing next to the pipette.