Does Activated Charcoal Whiten Teeth? Study Says No

clinical-trial PMID: 38316199

Quick Summary: A 2024 clinical trial tested activated charcoal powder and toothpaste for teeth whitening over 14 days. The study found these products only made tiny changes to tooth color, much less than a standard whitening gel. Researchers recommend skipping charcoal for better results.

What The Research Found

Activated charcoal products showed weak whitening power. The powder and toothpaste changed tooth color by just 1.1 to 1.3 units on a color scale (called ΔE, which measures how much color shifts). In comparison, a 10% carbamide peroxide gel (a proven whitener) changed color by 5.1 units. This difference was clear and significant (p<0.001), meaning it's not due to chance. Volunteers were least happy with charcoal—only 14% to 21% liked it—while 86% loved the peroxide gel. Charcoal caused almost no tooth sensitivity, but the gel did after about a week. Overall, the study says charcoal doesn't whiten well and should not be used for that.

Study Details

Who was studied: 56 healthy adult volunteers with normal teeth, split evenly into four groups of 14 people each.

How long: 14 days, with treatments twice a day for most groups.

What they took: One group brushed with activated charcoal powder (applied dry to a toothbrush). Another used activated charcoal toothpaste. A third used regular fluoride toothpaste as a baseline. The last group wore a tray with 10% carbamide peroxide gel for one hour daily.

What This Means For You

If you're searching for "activated charcoal teeth whitening" to brighten your smile at home, this study suggests it's not worth it. The color change from charcoal is so small (under 2 units) that you probably won't notice it—experts say changes below that aren't visible to the eye. Save your money for peroxide-based kits, which work better but might cause short-term sensitivity. Always talk to your dentist before trying whiteners to avoid enamel damage. Charcoal is great for other uses like filtering water, but not for teeth.

Study Limitations

Small groups (just 14 people each) mean results might not apply to everyone—bigger studies could confirm this.

Only 14 days long, so we don't know about long-term effects like if charcoal wears down enamel over months.

It was single-blind: Volunteers didn't know what they were using, but researchers did, which could slightly bias checks.

Didn't share details on ages or starting tooth colors, so results might differ for stained or older teeth.

No tests on the charcoal products' exact makeup, so purity could vary by brand.

Key Findings

Activated charcoal powder (ACPW) and toothpaste (ACT) demonstrated minimal whitening efficacy (ΔE = 1.1 and 1.3, respectively) after 14 days, significantly lower than 10% carbamide peroxide (CP; ΔE = 5.1, p<0.001). CP achieved optimal whitening and highest volunteer satisfaction (85.7%), while ACPW/ACT satisfaction was low (14.3–21.4%). Tooth sensitivity risk increased from day 7 onward in CP but remained minimal in charcoal groups. The study concludes activated charcoal products provide unsatisfactory whitening and should be discouraged clinically.

Study Design

This single-blind randomized controlled clinical trial enrolled 56 adult volunteers randomly assigned to four groups (n=14 each): activated charcoal powder (ACPW), activated charcoal toothpaste (ACT), regular fluoridated toothpaste (RT), and 10% carbamide peroxide (CP). Treatments were administered over 14 days with toothbrushing (test products) or whitening gel application (CP). Whitening efficacy was objectively measured using ΔE* (color difference) and subjectively assessed via volunteer satisfaction surveys. Tooth sensitivity was monitored throughout.

Dosage & Administration

ACPW was applied dry to a toothbrush before brushing; ACT was used as a standard toothpaste. Both were used twice daily for 14 days. CP (10% carbamide peroxide) was applied via custom tray for 1 hour daily. RT served as the negative control, used twice daily.

Results & Efficacy

CP showed significantly greater whitening (ΔE* = 5.1 ± 1.2) versus ACPW (1.1 ± 0.8), ACT (1.3 ± 0.9), and RT (0.7 ± 0.5) (p<0.001 for all comparisons). No significant difference existed between ACPW, ACT, and RT (p>0.05). Satisfaction rates were 85.7% for CP versus 14.3% (ACPW), 21.4% (ACT), and 28.6% (RT). Tooth sensitivity incidence rose after day 7 in CP (peaking at 35.7% on day 14) but remained ≤7.1% in all other groups.

Limitations

The study had a small sample size (n=14/group), limiting statistical power for subgroup analyses. The 14-day duration is insufficient to assess long-term efficacy or safety. Single-blind design (participants blinded, clinicians not) risks assessment bias. Demographic details (e.g., age, baseline tooth color) were not provided, potentially affecting generalizability. No chemical analysis of charcoal products was conducted to verify composition.

Clinical Relevance

Activated charcoal products offer negligible whitening benefits compared to established peroxide-based treatments, with minimal impact on tooth color (ΔE* <2.0, below perceptible threshold). Users seeking effective whitening should prioritize evidence-based methods like carbamide peroxide, despite associated transient sensitivity. The low satisfaction rates and lack of clinical benefit indicate charcoal products are not a viable whitening solution, supporting professional recommendations against their routine use for this purpose.