Sarah Creal Biocell Oxygen Serum Versus Sarah Ford Biocell Oxygen Serum

Unless it is specified to be non-alcohol, many types of witch hazel ingredients are distilled in denatured alcohol.

Witch Hazel water is an astringent, anti-inflammatory antioxidant, and antibacterial ingredient.

It contains tannins. Tannins have a drying effect when used on skin by constricting proteins. The constriction also minimizes the appearance of pores.

Both the tannins and fragrance found in witch hazel may be skin-sensitizing.

Witch hazel water gets anti-inflammatory and antibacterial properties from its catechin and gallic acid content.

Indigenous groups have used witch hazel to help treat inflammation in North America for centuries.

Our skin makes fewer of them as we age. This is a big part of why older skin heals slower and looks less bouncy.

The idea behind putting them in skincare is to "top up" the supply from the outside.

"Conditioned media" sounds mysterious but it's basically just leftover broth.

They're made in a lab where scientists grow human skin cells (fibroblasts) in a nutrient liquid. These cells release a cocktail of helpful proteins into that liquid as they live and grow.

Then, these cells are filtered out and the ingredient is the "conditioned" liquid now full of secreted goodies.

So what does neonatal mean here? It just means the original cells came from newborn tissue (usually donated foreskin), which tend to be younger, more active, and better at pumping out growth factors than adult cells.

Technically, this isn't one single ingredient, it's a mix of dozens of active molecules working together, including:

Studies find growth factor conditioned media can help with:

The evidence behind this ingredient is pretty solid too (and not just marketing).

A 24 week study of a fibroblast conditinoed media serum showed measurable improvements in the look of photodamaged skin, and these results were backed by actual skin biopsies rather than just before/after photoshoots.

And a broader review that pulled together many growth factor studies came to a similar conclusion: they generally help with fine lines, texture, firmness, and are well-tolerated.

It's also worth knowing the caveat that the review pointed out most of these serums also contained peptides, antioxidants, and exosomes.

The honest answer is there isn't a tidy "use at 1-2%" number the way there is for something like niacinamide.

This is because conditioned media isn't a single molecule. Brands add it as a percentage of a finished formula so that number is all over the map.

The serums built around it usually advertise very high levels (~50%) while others just use a splash. And the individual growth factors floating inside are actually present in very tiny amounts (think nano/micrograms per gram).

Here's one regulatory anchor point: the FDA has approved a wound healing gel that uses a pure growth factor at 0.01% (100 micrograms per gram). This shows the active growth factors themselves work at very low concentrations.

So the "50%" numbers you see on labels refer to the diluted broth and not the pure proteins.

The single most important thing to understand growth factors is that they are very fragile.

Dr. Zoe Draelos wrote this about them for Dermatology Times:

Independent lab work backs up the fragility.

Many growth factors lose a big chunk of their activity within a day or two sitting in water at room temperature and this is why smart formulating matters so much. Airless pumps, water-free formulas, and cool storage all help the ingredient survive long enough to do something. It's also a green flag if a brand can show real stability testing.

None of this means growth factor serums don't work; plenty of people get lovely results. It just means the formulation and packaging are doing a lot of the heavy lifting.

You may have heard a worry that growth factors "feed" skin cancer because their whole job is to encourage cells to multiply (this is called mitogenic activity).

It's a fair question to ask so here's the actual picture.

The theoretical concern is real enough that dermatologists take it seriously. There IS a hypothetical worry that they can encourage the wrong cells to grow in skin that already has sun damage or pre-cancerous spots.

Due to this, the cautious advice is to check with your dermatologist before using growth factor products if you have psoriasis, a history of skin cancer, or a lot of pre-cancerous sun damage.

Now the reassuring side:

There has been no documented pattern of growth factor products causing skin cancers despite millions of units sold over many years.

A large safety review of pure PDGF (one of the growth factors in these blends) found it to be non-toxic, non-mutagenic, and non-carcinogenic across decades of medical use. This is including repeated daily application to open wounds.

And a dermatology review specifically looking at topical EGF found no evidence that it stimulates cancer cells to grow (partly because these proteins are large and mostly stay near the surface).

The bottom line for a healthy person with no specific risk factor:

Growth factor conditioned media has a strong track record and is generally considered safe and well tolerated.

But be sure to loop in your dermatologist first if you have psoriasis, active or past skin cancer, or heavy sun damage. This is not because it's proven dangerous but because it's a sensible precaution while the long-term research keeps building.

The US allows human-derived growth factors so Human Neonatal Fibroblast Conditioned Media appears on labels.

In the EU, human-cell-derived ingredients are banned in cosmetics. EU products use plant-derived alternatives (barley is a common one) to get a similar effect.

In skincare, PC pulls double duty:

The linoleic acid it carries gets incorporated into skin ceramides and helps reinforce the lipid matrix.

Interestingly, it can help top of the omega-6 fatty acid that's often low in acne-prone and atopic skin. There's a sizeable body of literature that supports its use in dry, barrier-impaired, and breakout-prone skin.

There are two kinds of PC you'll see on ingredient lists.

Use levels range from <1% as a liposomal carrier and between 20-40% in lamellar matrix sytems.

Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.

According to a manufacturer, these ingredients encourage skin regeneration and smoothness by stimulating collagen and elastin production. A manufacturer study found creams containing 1–5% Antarcticine increased skin hydration and reduced wrinkle depth around the eyes.

The manufacturer also claims this extract can help regulate oily skin by reducing sebum production, shine, and minimizing pore size.

Some people have reported that ferments may trigger Malassezia folliculitis. For this reason, we list it as not fungal-acne safe, though individual reactions can vary.

Unlike other plant oils, jojoba wax doesn't easily penetrate skin. It mostly works in the uppermost layers as an emollient. This just means it forms a light barrier on the skin to help retain moisture.

Formulations with jojoba esters up to 90% reduced transepidermal water loss (TEWL) and increased barrier recovery by 81% (outperforming bisabolol at 47%).

Besides barrier support, the science also suggests jojoba to have anti-inflammatory effects and potential applications for skin infections, aging, and wound healing.

Fun fact: Indigenous cultures have used jojoba as a moisturizer and to help treat burns for centuries.

Fungal acne: The Malassezia yeast is known to metabolize fatty acids in the C11-24 range and jojoba's dominant fatty acid components fall into this range. This ingredient may not be fungal acne safe.

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!

Xanthan gum is a pretty common and great ingredient. It is a natural, non-toxic, non-irritating ingredient that is also commonly used in food products.