Thirsty Cowboy Cucumberita

A 2011 study found that cucumber fruit juice can fight free radicals and help protect two proteins that keep skin firm and plump (hyaluronic acid and elastin). This is why it's sometimes considered a potential anti-wrinkle ingredient.

Since this ingredient is usually used at low concentrations (up to 3%), it acts more as a soothing and skin conditioning ingredient than a powerhouse active.

They contain shikimate dehydrigenase, an enzyme shown to help reduce inflammation and soothe the skin.

The amino acids found in cucumbers help nourish our skin's natural acid mantle (it's an important part of our skin barrier). This slightly acidic film acts as a barrier to protect us from bacteria, viruses, and other contaminants.

Unless you have an allergy to cucumbers, this is generally a non-irritating ingredient.

Fun fact: Cucumis Sativus is native to South Asia and can now be found on every continent.

Here's what the research shows:

In-vitro shows it calms inflammation signals; the most skin-relevant study put a kelp extract on human skin cells and then hit them with inflammatory triggers. The kelp-treated cells produced less of the inflammatory messenger molecules that normally get released.

In a realistic 3D model of skin, the pre-treated tissue held onto its cell-to-cell "seals" better and leaked less water (basically the lab version of a strong vs. weak skin barrier).

Two honest notes: the seal effect only showed up in the 3D model and at higher doses the extract started harming the cells (so more might not be better)

Fucoidan is why kelp gets talked about; it's the sulfated sugar molecule that brands like to name-drop. When four fucoidans were compared, the one from Macrocystis pyrifera was the most active. Just know this was from immune research and not skincare research.

On real people, the numbers look good (with an asterisk). The strongest evidence is all on Macrocystis Pyrifera Ferment inside one company's finished serum and not the plain extract.

Using it twice daily for eight weeks raised skin moisture 16 percent and cut water loss through the skin by 11 percent. A stripping test that repeatedly tapes and peels the skin surface found treated skin held up 30 percent better.

The standout result: half the face was prepped for three weeks and then the whole face got a 70 percent glycolic peel. The prepped side had recovered 71 percent of its barrier versus 23 percent untreated two hours later. A separate review also reported less visible redness and improvement in visible aging measures.

Three asterisk: It's the ferment, not the extract. The kelp isn't necessarily doing all the work since it's the whole formula. And it was funded by The Estée Lauder Companies with several authors on staff.

There's no fixed concentration published for this ingredient but real-world use survey shows this ingredient can be used up to 36%. There's an extra wrinkle for leave-on products since these extracts are usually supplier pre-diluted in water, glycerin, or propanediol.So "5%" on the bottle might mean under 1% for actual kelp solids.

On allergies: kelp is naturally iodine-rich, so people with a known iodine or seafood ingredient sensitivity should patch test.

You'll see algae listed as a 5/5 on a lot of pore-clogging charts and that number doesn't come from anywhere; it's not in the original rabbit-ear studies that most comedogenic ratings trace back to.

The reasoning behind the reputation is that seaweed is high in iodine and iodine can trigger acne-like breakouts when eaten. This traces back to a 1976 letter in Archives of Dermatology describing two women whose breakouts cleared after they stopped taking high-dose kelp supplements orally.

And the reaction of these two women wasn't clogged pores at all: it was an iodine-triggered pustular rash. Later research found normal dietary iodine doesn't meaningfully affect acne either and nobody has shown topical algae delivers enough iodine to matter.

What we do have is dozens of brown and red algae ingredients found to be non-irritating and non-sensitizing, and a handful of studies that found algae compounds may actually help acne.

However, plenty of people do report breaking out from algae-containing products. Skin is individual and it's worth avoiding if yours has reacted to algae before.

Studies show green tea extract and its catechins (like epigallocatechin gallate (EGCG)) help your skin cells product energy more efficiently and reducing the number of free-radicals that can damage your skin from the inside.

In lab-grown skin models, this translated to younger, healthier, and stronger skin.

There's also good sun protection data; researchers saw less DNA damage and redness on human skin when green tea was applied before UVB exposure. And the more they applied, the better the protection.

Needless to say, this ingredient shouldn't replace your sunscreen. But it is a great supportive ingredient that you can already find in many sunscreens and antioxidant serums.

A 2009 study found a 2% green tea lotion was effective for mild-to-moderate acne thanks to its anti-inflammatory and mild antimicrobial activity.

The quality of the extract matters a lot here:

Good extracts contain 50-90% catechins while lower quality ones are mostly there for marketing. We recommend reaching out to the brand if you have questions about the quality or source of their ingredients.

Human Repeated Insult Patch Testing showed no irritation or sensitization at use concentrations (0.86% in leave-on products and up to 30% as leaf water).

This ingredient may help soothe your skin by reducing inflammation. Emerging studies show it inhibits nitrous oxide production safely, therefore reducing inflammation.

Marigolds have been used in traditional medicine throughout Asia and Europe.

And of course, lemons are rich in Vitamin C. Vitamin C helps with skin-brightening and increasing collagen production.

The acidity of lemons may work as an astringent for acne.

However, lemons can also cause skin sensitivity due to its limonene content. It can also increase photosensitivity, or sensitivity to the sun.

This ingredient is also used to add a lemon scent to products.