DermaHarmony 10% Sulfur Bar Soap

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!

Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.

Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.

This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.

Just know very high concentrations (>40%) can feel tacky in low humidity.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

Terpinen-4-ol is responsible for tea tree oil's broad-spectrum antimicrobial activity and makes it a well-researched option for acne.

Clinical studies support 5% tea tree oil as an effective topical treatment for mild to moderate acne. A study with 124 patients compared 5% tea tree oil gel to 5% benzoyl peroxide and both reduced acne (though tea tree oil worked more slowly).

Besides acne, it is also seen in anti-dandruff shampoos and scalp treatments for it's antimicrobial and anti-seborrheic properties.

Safety-wise, the allergic potential of low concentrations on healthy skin is considered low. However, oxidized (old or improperly stored) tea tree oil is a stronger sensitizer.

Irritation can also occur if using the undiluted oil on skin; it's best to use this ingredient as part of a carefully crafted cosmetic formula. This is because regulations require tea tree oil in cosmetics to be stabilized to prevent degradation.

This ingredient has been deemed safe up to 2% in shampoo, 1% in cleansers, and 0.1% in face cream by the EU's Scientific Committee on Consumer Safety (SCCS).

There is some lab evidence that tea tree oil is antifungal against Malassezia, but it is a supportive option at best and not a replacement for proven antifungal treatments.

You might see people debate whether Sodium Chloride is comedogenic, but there actually haven't been any comedogenic tests done on it. Either way, the overall formulation of a product matters a lot more than any single ingredient.

You might see this ingredient used in scrubs as a primary exfoliating ingredient.

Direct research on this extract is limited and mostly comes from supplier safety dossiers:

Human testing found it to be non-irritating or sensitizing in a 50-subject occlusive patch test.

Real-world concentrations are very low: industry survey data puts it at 0.0007% to 0.02% in face and neck products, 0.0005% in moisturizers and cleansers, and up to 0.04% in hair conditioners.

Most human clinical skin research on coconut is on virgin coconut oil and not this extract. For example, a randomized double-blind trial found virgin coconut oil as effective and safe as mineral oil for mild to moderate xerosis with significant improvement in hydration and skin surface lipids. However, you can't transfer that to a water-based fruit extract at 0.01%.

There's no comedogenicity data for this specific ingredient; the "coconut clogs pores" reputation comes from coconut oil which scored high on the old rabbit ear assay.

That method tested pure ingredients on rabbit ears and later work showed the results translate inconsistently to human skin.

Some people still find it breaks them out. So if that's you, definitely trust your skin.